Hard Solder

As used for brazing, hard solder is generally a copper/zinc or copper/silver alloy, and melts at higher temperatures than tin/lead compositions.

In silversmithing or jewelry making, special hard solders are used that will pass assay. They contain a high proportion of the metal being soldered and lead is not used in these alloys. These solders also come in a variety of hardnesses, known as 'enamelling', 'hard', 'medium' and 'easy'. Enamelling solder has a high melting point, close to that of the material itself, to prevent the joint desoldering during firing in the enamelling process. The remaining solder types are used in decreasing order of hardness during the process of making an item, to prevent a previously soldered seam or joint desoldering while soldering a new joint. Easy solder is also often used for repair work for the same reason. Flux or rouge is also used to prevent joints desoldering.

Liquid Flux Use

Liquid Flux

It is important to put the minimum amount of liquid solder on the copperfoil seams. A surplus of liquid flux will bubble and splatter, leaving holes in the solder bead. Cutting your flux brush about in half, at a slight angle will reduce the amount of flux on your brush and ease the application.

Pour a small amount of flux, just enough for the task at hand, into a small container. Don't pour the leftovers back into the flux jar, it will contaminate the rest. Do not use the lid of your current flux jar, as it should be sealed at all times so it won't become sticky by evaporating.

When finished soldering, wash off the flux by washing it with warm water and a very little dish washing liquid and a soft sponge, then rinse with water. Clean your flux off right away after you finish soldering. Flux will oxidize your solder seams if left over time. It also becomes more difficult to remove when it has begun to dry.


See also:
Flux, an introduction
Fluxes, a description
The Purpose of flux
The action of fluxes
Soldering fluxes

Combination Grozing/Breaking Pliers

Description
The jaws of grozers are serrated and used to gently remove small pieces of glass which remain after the glass has been scored and broken. They are normally supplied with one straight jaw and one curved making them combination grozing and breaking pliers.

Use as breaking pliers
When used as breaking pliers the flat side should be up and the nose of the jaws almost touching the score line. The breaking pressure should be down and slightly to the side to bend and pull the piece away from the main piece of glass.

Use as grozers
When used a grozers – to gently wear away some small part of glass - the curved jaw should be up. The plier jaws should be used slightly open, and a downward motion of the plier does a “rasping” of the glass edges, taking away small bits of glass. With experience, a lot of glass can be removed quickly shaping the glass with a fair degree of precision. The edge can then be tidied by a grinder if required.

Waxing up Recipe

Beeswax alone isn't good for waxing up glass pieces on a glass easel, but combining it with Venice Turpentine makes a secure fixing material.

Recipe
250gm block of beeswax
2 teaspoons of Venice Turpentine

Method
Bring the two elements just to a simmer, stir it well and cool.

This produces a tacky material that when warmed in the hand sticks to the glass and the easel. When it cools it sticks firmly.

Use a palette knife to loosen the wax from the easel.

Hanging Panels - Hooks

If you wish to attach hooks to the panel so that the appropriate chain length for its setting can be attached later, you need to use brass or other strong metal that can be securely attached to the frame of the panel.

An easy solution is to use brass chain links. Cut one link from a suitably heavy chain at the centre of the long side of the link. Straighten one part of the opened link with two pair of pliers or a vice and pliers. Solder the straight leg with the open part of the hook facing outwards, to avoid the chain (which is pulling inwards) from slipping out of the hook. The open part of the hook should give only enough room for the chain links to be inserted between the frame and the opening of the hook

Hanging Panels – Chain, Wire, Line

The choice of hanging material is both aesthetic and practical.

Whatever material is chosen must be strong enough to support the panel over a long time.

Chain is reliable and can be obtained in many sizes, styles and metals. You can use a split ring to join the chain to the loops on a panel, or directly if the panel has been fitted with hooks.

Twisted picture wire is a reliable material too. It normally is twisted brass with at least one steel strand embedded. It can be soldered at various points around the panel and at the place where the eye if formed to insure that the twists will not come undone.

Fishing line can be used. You should use the highest test you can find. 50 pound test is sufficient but still not obtrusive. However, it is subject to deterioration with constant light exposure, and so should be renewed every 4-5 years. Also you need to be careful in the knots you use. It is very slippery and a surgeon’s know should be topped up with a second for security.

Fine cable enclosed in plastic can also be used. This is fine enough that it can be tied, but should be joined with knots that cannot slip.

Refining Edges

You can make the freshly cut glass safer to handle by gently wiping the edges of the cut piece with the waste piece. This removes the sharpest edges without chipping the glass.

After the glass is scored and broken, you can remove small, unwanted chips with grozing pliers. The serrated jaws of these pliers are used to gently nibble away at the jagged edges.

Rough edges can also be smoothed with a carborundum stone. You rub the stone along each edge, upper and lower, to remove any sharp edges. You can remove more glass with the stone if you wish by a little more aggressive grinding action or just a longer light rubbing of the stone against the edges.

A diamond smoothing pad removes glass in much the same way as a carborundum stone, but does it more quickly with the coarser grades. You can use a number of grades to get an almost bright polish to the edges. These pads must be used with water.

A glass grinder is used by many people. Many models of grinders are available. The grinding surface of the bit is covered with fine diamonds, which grind away unwanted glass very quickly without chipping the edges. In addition, they are water-fed which keeps the glass from cracking due to heat, prolonging the life of the diamond bit, and preventing the powdery ground glass form flying around.

A glass grinder is not a substitute for accurate cutting.

Silhouettes in Leaded Glass

There are also times when you may want to have a silhouette, you can cut it out of lead foil and solder it into place. This allows intricate shapes to be made when a dark representation of the shape is required. If the panel can be seen from both sides, the overlays should also be on both sides. This can be applied to copper foil too.

Representing Acute Angles in Leaded Glass

False lines are used in leaded glass where the design calls for an angle that cannot be cut into the glass. This includes right angles and even more acute angles. E.g., the petals of a fuschia flower. The design would call for an angle of about 60 degrees. This is impossible to achieve through cutting. So the glass is cut in a curve and the cames on the side and bottom of the petal have their hearts cut out so they overlap each other. The overlap is then trimmed to the shape of the outside of the petal. When soldered, the appearance is of the glass being cut at the angle required for the flower.

Dams for Drilling

For those who find putty or plasticene too insecure, it is possible to use a plastic bottle with the bottom and top cut off, and secured with hot glue. This will provide a non-slip dam for the water while drilling.

Glass Painting Tools

The tools needed for glass painting are few and relatively common, although the blender is specialised. The minimum you need are:

Glass palette –
A slightly etched glass sheet on which to grind and mix the paints

Palette knife –
A paint knife with a flexible metal blade used to mix and pile the paint

Tracing brush –
A thin and long-haired brush used to apply paint to glass. Sable is considered superior, as it can hold a lot of paint allowing long lines.

Badger blender –
A wide and flat brush made of badger hair used to blend or evenly disperse a layer of paint on the glass, or to stipple a fine layer for a pin-hole effect

Stippler –
A round, thick brush used to apply wet paint and create a stippled matt

Soldering Irons and Rheostats

People often want to have variable temperatures for decorative soldering.

It is often recommended to use a rheostat in circumstances where the soldering iron does not have an internal temperature control. The rheostat reduces the current reaching the iron. The degree to which you have to do this is related to the speed or amount of work you are doing with the iron. With reduced current, the iron can not build up to its previous temperature so quickly. Therefore, it is a matter of individual practice on the rheostat setting you use.

Temperature controlled soldering irons attempt to maintain a set temperature. This is controlled by the combination of the microchip in the iron and the tip. So to adjust your temperature all you need is a few different tips. For example, a number 7 tip lets your iron heat to 700F degrees. For decorative soldering your need tips of lower temperatures, usually a number 6 or 600F degree is enough of a reduction for most decorative stuff. A number 8 tip (800F) will let you work at a higher temperature if you work quickly.

You can buy an iron (not temperature controlled) and a rheostat but buying tips for the temperature controlled iron is cheaper. A rheostat is NOT a temperature controller. A rheostat actually reduces the power supplied to the iron, thereby making it take longer to heat or re-heat after a period of soldering. Many people advise that using a temperature controlled iron with a rheostat can damage the thermostat. Using an iron without a rheostat, provided you work relatively quickly, you will probably be able to solder all the joints in a small or medium panel without stopping to let the iron 'catch up'. In this case the temperature is controlled by the heating power of the iron balanced by the cooling effect of making the soldered joints.

With a temperature-controlled iron, if it is left idle, it will quickly reach its maximum operating temperature - just as quickly as an uncontrolled iron of the same power. When you start soldering, the cooling effect will trigger the temperature controller to provide full power until the operating temperature is reached again. Using an iron with a rheostat, you will need to slow down a little if you are to do that same panel without stopping to let the iron re-heat. In this case the temperature of the iron is controlled by the (reduced) heating power of the iron balanced by the same cooling effect of making the soldered joints.

Without a rheostat, if an iron is left idle, it will eventually reach its maximum temperature. This is usually too hot for soldering lead, but OK for joining other metals. With a rheostat, if an iron is left idle with the rheostat set to (say) '6', it will still reach its maximum temperature but very much slower than the one without a rheostat.The big advantage of the temperature-controlled iron is that you know it will never get too hot for the work you are doing, and that it truly provides that 100 watts (or whatever) power to keep it hot even when you are soldering at top speed.

Soldering Irons

GeneralHistorically soldering tips were copper, placed in braziers. One tip was used, when the heat had transferred from the tip to the solder (and depleted the heat reserve) it was placed back in the brazier of charcoal and the next tip was used.

Much later gas irons were in common use. These used a gas jet to heat the soldering bolt/tip. They are very fast, but require significant amounts of experience to properly regulate the temperature.

Currently, electric soldering irons are used; they consist of coil or ceramic heating elements, which retain heat differently, and warm up the mass differently, internal or external rheostats, and different power ratings - which change how long a bead can be run.

SelectionThe soldering iron used must be of a high enough wattage to readily melt the solder and be able to reheat fast enough to maintain the necessary melting temperature. The tip can't be so small it can't maintain the heat and not so big it covers more area than wanted.

For soldering leaded panels a 100w iron with a 3/8" temperature controlled tip that maintains a constant 370°C (700° F) is suitable.

For copper foil a higher temperature controlled tip is used. This normally runs at 425°C (800°F). Sometimes a tip of ¼” is used where more delicate beads are being run.

If a lot of soldering is required that has sustained heat requirements, you might consider a 200W iron. These can deliver heat more quickly and evenly than those with lesser wattage.

Silver Stain as a Colour Modifier

Silver stain can also serve a useful purpose to modify the colours of glass. If you add a silver stain pattern to a piece of light blue glass, for example, the result will be a green pattern. This creates all sorts of creative opportunities, particularly when used in conjunction with etched flash glass.

It is also possible to use the silver stain successfully with other paint and enamel colours to warm the colours.

Silver Stains - Mending Mistakes

If the stain did not take, there are techniques to try and improve the colour.

One is firing the silver stain face down on a sifted and smoothed out bed of whiting or thick ceramic fiber paper.

Another is to re-apply your stain and fire again between 675°C (1250°F) and 760°C (1400° F). The higher heat will help the silver stain "take" to the glass. Fire the silver stain face down because the higher temperature will melt the high fire tracery and matting resulting in kiln-wash sticking to the painting.

A third method is to use hydroflouric acid to remove the stain and so start again with clear glass. Remember this is an extremely dangerous chemical.

After a second successful firing, be sure to discard the loose whiting or shelf paper from your kiln-shelf as any residual silver stain absorbed during the firing can result in yellow spotting on your glass on later firings.

Firing and Cleaning Silver Stain

After the silver stain has completely dried, the glass is ready to fire in the kiln. Remember to fire silver stained items separately from other painted glass. The maturing temperature is between 509°C (950°F) and 565°C (1050° F). Place the glass on the kiln shelf with the painted side down and the silver stain facing up. Fire between 509°C (950°F) and 537°C (1000° F) for softer glasses, and to between 537°C (1000° F) and 565°C (1050° F) for harder glasses. The higher temperatures in each range will result in darker colour.

After firing and cooling remove your glass from the kiln. The glass will look exactly as it did when you first placed it in the kiln, as though it hasn't fired. In fact, the firing process will have done its job, but first you must remove the residual layer of gamboge gum. Simply spray with window cleaner and wipe off. Underneath, your glass should be stained some lovely shade of golden yellow.

Hanging Panels – Perimeter Wire

Often it is most secure to have the bottom of the panel supported, rather than relying on attaching hooks or loops to the edges of the panel.Panels with “H” lead came are the easiest and neatest to form a wire around. You can use twisted brass picture wire (which has a steel strand embedded) for this purpose or solid copper wire. When using picture wire, form a loop at one end by twisting the strands. In this example I am using solid copper wire.

Make a loop as described.


Open the leaves of the came at the top and solder the wire with the loop to the heart of the came. Use as little solder as possible and keep it away from the leaves, as solder on the leaves makes folding the leaves back very difficult.

Continue the wire around the side. Pull the wire tight and tack solder the wire at the bottom of the side. Continue the wire around the bottom and do the same at the other side.

Pull the wire tight to the top of the panel. Bend the wire over at the height you wish the loop to appear above the panel. Twist or bend the wire and solder it to the side of the came’s heart.

Close the flanges of the came over the wire and you have a neat finish to the edges.

You can, of course, decide to hang the panel from the wire going around the panel. In this case you eliminate the loop forming at each side of the panel’s top. I solder the wire ends together at the bottom, in addition to soldering the wire to the came at each corner. This provides me with the certainty that the wire will not come loose.

This can also be used to provide the hanging supports when placing the panel in a wooden frame. It takes the strain off the frame but still provides firm support of the panel.

Applying Silver Stains

Introduction
Contrary to its name, silver stain actually stains the glass yellow. Silver stain is available in shades from pale yellow to deep orange. Today the use of silver stain remains a popular choice for the glass painter with no other pigment matching its delicacy and wholly translucent quality. Silver stain is composed of silver nitrate and gamboge gum, a resin from Southeast Asian trees. It is sold in powdered form and is mixed only with water. A separate set of tools is required for silver stains as the stain itself is terribly corrosive to brushes and other tools.

Application
To use, the artist mixes the powdered stain on a glass palette to a thin consistency. This can either be applied thinly in a free-hand manner to the back side of the glass painting, or applied and quickly blended to smoothness with a badger blender for a more even result. Always apply the silver stain to the back side of the glass - in other words, the opposite side from the one that bears the tracery and matting you have previously completed. There are several reasons for this, but the primary one is that the silver stain will metallise the black and brown paint work during firing if applied to the same side. This metallising results in a strong bluish and opaque haze on the tracing and matting.

During application, be sure to work rapidly and evenly, finishing before the wet stain has a chance to completely dry. Also remove the excess stain while the stain is still damp. Scraping off the run-over will prove to be quite a challenge if you let it dry. When you have completed these steps, immediately wash your tools.

Tempered or Toughened Glass

Toughened or tempered glass is a type of safety glass that has increased strength and will usually shatter in small, irregular pieces when broken. It is used when strength, thermal resistance and safety are important considerations.

Toughened glass is made from annealed glass by a thermal tempering process. The glass is placed onto a roller table, taking it through a furnace which heats it to above its annealing point. The glass is then rapidly cooled with forced draughts of air to below its annealing point, causing it to harden and contract, while the inner portion of the glass remains free to flow for a short time. The final contraction of the inner layer induces compressive stresses in the surface of the glass balanced by tensile stresses in the body of the glass.

It is this compressive stress that gives the toughened glass an increased strength - typically four to six times the strength of annealed glass. The pattern of cooling during the process can be revealed by observing the glass with polarised light, which shows the strain pattern in the glass.

See also Prince Rupert's Drops

Soldering 3-D Pieces

When soldering 3-D pieces together, first tack the panels together with a single tack at each end. If it later turns out that there is an alignment problem, it is much easier to dis-assemble a few tacks, with a piece of paper inserted into the space between the pieces of glass and moved up into the molten solder while your iron is at the tack joint. The paper will strong enough to move through the solder, separating the two piece of glass.

Once your 3-D piece is tacked together and looks OK, turn the piece over on its side, and, using 50/50 or 60/40 solder, fill in the inner seams, moving the piece around. Be careful to support the piece with boxes or blocks and by holding it at the top part above where you are soldering, to prevent the piece collapsing.

Once the inside of the piece, say a panel lamp, has been soldered smoothly with 50/50, turn the lamp over. Get a few boxes or similar supports to prop the lamp up against, and make it so that there will be a level solder seam. Using the 50/50 solder again, fill in the seam. It doesn't have to be perfect, at first. Do all of the seam filling first, to ensure the stability of the piece. Then go back with 60/40 solder and, again making sure the lamp seams are level, finish by smoothly soldering each seam.

Perimeter Foils

Foil pulling away from the glass on perimeter

If this is happening to you, there are several things to remember.

Clean all the edges and surfaces just before foiling. This ensures there are no oils to interfere with the contact adhesive of the foil. Avoid hand creams just before foiling as this increases the amount of oils getting onto the glass.

Remember that lots of heat breaks down the adhesive. So do not remain in one place too long. However the adhesive is not the element that keeps the foil attached to the glass in the long term. Instead, think about whether the bead on the edge is thick enough to provide the rigidity required without relying on the adhesive of the foil.

Finally, think about whether an edging came would provide better support and finish to the piece.

Media for Glass Enamels and Paints

Mixing agents
These are the carriers that give "tooth" to the paints and are water-based or oil-based.

Common water-based media are:
· water & gum arabic,
· wine,
· sugar water,
· vinegar

Common oil-based media are:
· clove oil,
· lavender oil,
· damar varnish

Gum arabic
This natural gum (also called gum acacia) is a substance that is taken from two sub-Saharan species of the acacia tree, Acacia senegal and Acacia seyal. It is used primarily in the food industry as a stabliser, but has had more varied uses in the past, including viscosity control in inks. For artists it is the traditional binder used in watercolour paint. It is sold in powder and liquid forms.

Dammar gum
This is obtained from the Dipterocarpaceae family of trees in India and East Asia, principally those of the genera Shorea, Balanocarpus, or Hopea. Most dammar gum is produced by tapping trees, however some is collected in fossilised form from the ground. The gum varies in colour from clear to pale yellow, while the fossilised form is grey-brown. It is used in foods, as a glazing agent, and in the making of incense, varnishing and in other processes. Dammar was first introduced as a picture varnish in 1826 and is commonly referred to as Damar varnish.

Lead Came

Lead came is often just called came. There are two basic types of lead: hard lead and soft lead.

Soft lead is 100% pure lead with nothing added. Soft lead strips need to be straightened in order to remove the propensity to stretch and sag. The advantage of soft lead is being easier to bend and shape to curves and that straightening removes any kinks in the length. Within 50 years it will need to be replaced.

Hard lead has antimony added which stiffens the lead. This results in a stronger finished panel. However this kind of lead deteriorates relatively rapidly. The advantage of hard lead is the added strength and not having to stretch it. It will need to be straightened just before use though. It is still malleable enough to conform to most curves.

Came is available in many shapes, although H, U and C are the most common. The lengths are usually about 2 meters (6 feet). C and U shaped lead is used on the outside of a panel. H shaped lead can be used on both the interior and edge of a panel.

The came’s top and bottom are the flanges and the width of the flange is the nominal size of the lead. These flanges can be flat (parallel surfaces) or rounded (a slight dome on each of the flanges). The central part of the came is called the heart, normally 1.2mm (1/16”) thick.

Lead Knife

Description
The lead knife is used to cut the lead cames. There are many kinds of lead knives on the market. They fall into two basic types – the curved blade and the straight blade.
This is a necessary tool because lead dikes can't achieve acutely angled cuts readily.

Use
The important things to remember are to lubricate the blade, to maintain the proper angle, and to keep the blade sharp.

The blade is lubricated by wiping it through beeswax. Beeswax is slightly sticky so it will adhere to the metal better than ordinary wax. This greatly increases the ease with which the knife will slip through the lead.

The proper angle is maintained by keeping the blade in a line between your eye, the handle, and the blade where it contacts the lead. To push the blade through the came, you need to wiggle the blade from side to side (for a straight edge) or to rock it (for a curved blade) as you apply downward pressure. Too much pressure in relation to the wiggling or rocking movement will cause the lead to be crushed. Too little movement, will make the cutting slow.

Additional use
The lead knife can also be useful in positioning the lead around the pieces of glass, usually by gently pushing on the heart of the lead.

Common Solder Compositions for Stained Glass

Common solders for stained glass are mixtures of tin and lead, respectively:

• 63/37: melts at 183°C (362°F)
• 60/40: melts between 183°C (362°F) and 188°C (376°F)
• 50/50: melts between 183°C (362°F) and 212°C (421°F)
• 40/60: melts between 183°C (362°F) and 234°C (454°F)
• lead-free solder (useful in jewellery, eating containers, and other environmental uses): melts between 118°C (245°F) and 220°C (428°F), depending on composition.

The 63/37 and 60/40 solders are most often used in copper foil work because of their smaller melting range. This allows the solder to set more quickly than the solders with higher lead content. They tend to give smoother beads also.

50/50 and 40/60 solders are more often used in leaded panel work. Their wider range of melting temperatures allows the solder to spread and become flat.

Lead Dykes

Description
Lead dykes are used to cut the lead came when the angle to be cut is oblique. The cutting edge of the tool is flattened on one side and is very sharp. This is a tool where you get what you pay for. It should be spring loaded to return to the opened position readily. The jaws should move freely and easily and should be large enough to span 3/8" lead.

Use
The tool is held with the jaws pointing down with the flat side of the tool facing the side of the lead you want flat. The lead is held oriented as it will be used. The tool will be cutting into the sides of the lead strip, not from the top and bottom of the came. When cut and observed directly from the top, the upper came flange should be directly over the bottom flange. If one flange extends beyond the other, there will be a gap where the cames meet.

Observation
This is a tool that cuts square or nearly square angles on came quickly and neatly. It is not very good for angles. A lead knife is better there.

Loops for Hanging Panels

Loops


These can be made from copper or brass wire. The single strand wire is better than twisted strands.

Take a length just over twice the length to be covered. The larger or heavier the panel, the longer the loop should be. Bend the middle over a nail to maintain an “eye” space at the middle.

Hold the tails so they do not overlap or twist when closing the legs to form the eye.


Grasp wire with the pliers just below the bend and close the loop.

Inserting chain into the loops can be done at the time of forming the loops, thus avoiding the need to split chain links and re-solder them.

Alternatively, you can open a chain link, insert it into the loop’s eye and solder it closed afterwards.

If you are using fishing line or other lines or wires that can be joined or tied, you can insert them into the loop eyes later.

Pattern Cutters

These are really only needed when the glass is so dark that a light table does not transmit sufficient light through the glass to see the cartoon lines. An alternative is to cut at the side of the cartoon lines, leaving the appropriate sized pattern piece.

Pattern shears
Pattern shears are specially designed three-bladed scissors that are used to cut out patterns. The middle blade cuts out the allowance for the heart of the lead came or copper foil. Different shears are available for lead or foil work. The allowance for lead came is usually 1.5mm; foil allowance is 0.75mm.

Pattern Knife
Knives with two parallel blades properly spaced for the lead came or foil allowance are also available for pattern cutting. These are ideal for tight curves, as they are easier to manipulate than shears.

Breaking Pliers

Description

The breaking plier is a special stained glass tool that has smooth jaws that meet at the tip of the pliers. This enables the tool to reach over the top and bottom of the glass with only the tip coming into contact with the glass exactly against the score line.

Use

The plier handles are held at a right angle to the score line. The edge of the glass needs to be close enough to the score line in order to use this tool, as the tip of the jaw needs to be against the score line. It is used in lieu of your hands when the piece being broken off is too narrow to be comfortably grasped by hand. When bending the glass, the top jaw comes down flat against the surface of the glass (that's the reason for the smooth jaw) and as the bending pressure is applied, lateral/pulling pressure is applied at the same time. This tool can also be used to groze the glass by carefully nibbling away the edge.

Note

If the score line is further than 20mm away from the edge, cut running pliers are the appropriate tool to use.

Cutting Circles from Opalescent Glass

Score as normal.

Be careful about putting too much pressure when scorning as, in general, opalescent glass does not make as much sound when being scored as transparent glasses do.

The difficulty with opalescent glass is seeing where the score is when you turn the glass over.

If you are using a piece of glass not much larger than the circle you are cutting, you can place the fingers of your hand over the score line and your thumb on the back as you lift the glass to turn it over. This gives you the location to begin the pressure to run the score. As the first part of the score runs, you will be able to follow the leading edge of the opening score around the circle.

Removing Silicone

Before it cures:
To remove silicone before it is cured, use a putty knife to remove any of the uncured paste. Wipe the area clean with isopropyl alcohol to remove any leftover residue.

After it is cured:
First you should mechanically remove as much of the silicone as you can with either a knife or a razor. A solvent can them be used to remove any oily residue or any remaining silicone. It may be necessary to soak the silicone in a solvent overnight to break it down.

Below is a list of solvents in the order of aggressiveness in attacking the silicone:
· Paint thinner (mineral spirits)
· Toluene
· Xylene
· Acetone
· Methylene chloride.

When using solvents, as with any material, proper safety precautions should be observed.

Properties of Glass

Mechanically Strong
Glass has great inherent strength. It is weakened only by surface imperfections, which give everyday glass its fragile reputation. Special tempering can minimize surface flaws.

Hard
The surface of glass resists scratches and abrasions.

Elastic
Glass gives under stress - up to its breaking point - but rebounds exactly to its original shape.

Chemical Corrosion-Resistant
Glass is affected by only a few chemicals. It resists most industrial and food acids.

Thermal Shock- Resistant
Glass with stands intense heat or cold as well as sudden temperature changes.

Heat-Absorbent
Glass retains heat, rather than conducts it. It absorbs heat better than metal.

Optical Properties

• Reflects
• Bends
• Transmits
• Absorbs light with great accuracy.
  

Electrically Insulating
Glass strongly resists electric current. It stores electricity very efficiently.

Soldering Copper Foil

Tip sizeSoldering copper foil is ideally done with a smaller tip than for leaded glass. A 3/16" long taper tip is useful. Use the tip on edge rather than the flat side in order to minimize the iron's contact with the glass. Thus, the iron is held almost vertical. Foil heats up very fast and too much heat can crack the glass so the narrower the iron contact is the lower the risk.

Solder applicationThe solder is applied in one of two ways. The quickest method is to feed solder in on the thicker part of the shiny tip and let it flow down to the foil. The iron is held firmly against the foil and pulled along the foil (which has been fluxed) at the proper rate with the solder being fed at the correct rate in order to produce a slightly rounded, shiny solder bead. Don't try and "float" the iron on top of the solder, be firmly down against the foil. This requires practice to match the speed of movement and the amount of solder fed to the iron.

Alternatively, you can do the Bunny-Hop method. This is easier to control and is done by soldering one tip-length, lifting the iron and soldering the next tip-length, barely re-heating the section just soldered. A variation on this is to place blobs of solder at regular intervals along the foiled and fluxed joint and then move the iron along the joint melting the blobs as you go. This avoids the tide marks at the cooling ends of the solder bead.

Matting in Glass Painting

To give your stained glass design a bit of dimension, you need to try a technique called matting. Some use a stippled matte almost exclusively in their glass painting to prevent a heavy-handed look in the end result. It is also a good deal easier to achieve than a flat matte, especially for the novice.

Application
You may use black or bistre brown for matting. For the sake of practice, mix a batch of bistre brown paint on a new palette (always use a separate palette for each color of paint) and follow the steps used for mixing black. On another clean piece of glass and using your small brush, quickly apply bistre brown paint over the entire surface. Then, while the paint is wet, take a large soft blender brush and gently sweep vertically over the glass, then horizontally, blending the paint as evenly as possible.

Blending motion
This sweeping motion should be made from the elbow to give an even blending of the paint. If done from the wrist, the paint will be moved in localised areas. This can be used to give a fine graduation in tone, but is not suitable for an even blend of paint over an area.

Stippling
When the paint begins to dry in streaks, immediately begin a gentle up-and-down pouncing motion on the glass. This stippling technique creates a pin-hole effect over the glass surface allowing light to sparkle through. It helps avoid the muddy opaqueness resulting from simple blending that often destroys the translucent beauty of the glass; and the effect of good glass painting.

Blender
If you like the "look" of matting and intend to use it often, you should acquire one other brush that will serve you well - a 3"-4" badger hair blender. Nothing accomplishes even blending as well and as quickly. Blenders are, however, a bit pricey. These brushes are an investment well worth the cost and they will last for years with good care.

Firing
It would be helpful for you at this point to fire your practice pieces in a kiln to check the results of your paint mixing and painting techniques. The black and brown pigments are high-fire paints and will need to be fired to 650°C (1200 °F) or a little higher for float glass. Correctly fired colours should acquire a translucency and should clearly appear to have fused with the glass.

Tinning brass

Brass transmits heat much more quickly than lead, so a considerable length or the whole of the piece, e.g., a vase cap needs to be heated to avoid the cap acting as a heat sink and so not allowing even tinning of the object.

When tinning any brass pieces, like a lamp cap, rub it with fine grade steel wool (often labeled 000) until bright, then wash the residue off and dry. Apply flux with a fresh flux brush, and hold the piece with a pair of pliers.  Brass transmits heat much faster than lead or solder, so this is a precaution against getting burnt.

At this point you can heat the brass or vase cap with a low heat blow torch to warm the whole piece. When warm, turn off the blow torch and begin applying the solder with the soldering iron.  Touch the piece with your hot soldering iron, pause and then start moving the iron slowly and smoothly over where you have applied the flux, applying a little solder all the time.

Alternatively you can work without the blow torch. Apply a bit of solder to the tip of the iron. Touch the piece with your hot soldering iron, let the piece heat up a little, and then start moving the iron slowly and smoothly over where you have applied the flux.

When the whole piece has been covered, wash it, dry, and then inspect for any missed spots or unsightly solder blobs. Apply a little bit more flux and touch with your soldering iron. If you are doing a lot of this kind of work, an 800 degree iron tip will speed up your work.

Suncatcher Edges

When finishing soldering on a suncatcher, coat the edges with flux, tin the upper edge with solder, repeat on the other side, then flux and tin the outer flat edges, with 60/40 solder. Then hold the suncatcher with a pair of pliers, in a vertical position, and begin to apply the solder in small amounts along the top edge, moving the piece around so the top edge that is level changes. Then go back and connect the little blobs with more solder.

Building up the edge of suncatchers helps the foil from being ripped off accidentally, or just peeling back on its own from being damaged during the cleaning process. This will also allow you to bury a length of fine wire (20 gauge or 22 gauge) around the outer edge of the suncatcher. This provides reinforcement, especially if the suncatcher has a design that has a part of it sticking out on its own, unsupported by the main body of the piece.

Cutting with Patterns or Templates

As a general rule, always make the hardest cut first. Glass tends to run in a straight line. This means inside curves should be done before any other cut is made.

It will be most efficient to place the pattern to be cut with the inside curve facing the raw edge of the glass. If something goes wrong, the pattern can be backed away and tried again, resulting in less glass and time wasted.

It is also hard to break very thin strips of glass away from the desired piece without getting ragged, chipped edges. Allow a 6 mm minimum distance from the edge of the glass when placing the pattern on the glass unless the edge is going to be used for the whole edge of the piece.

When scoring around a paper pattern it is necessary to steer (turn) the cutter in the proper direction. The paper will not turn the cutter for you. You should steer the cutter by turning your upper body rather than your fingers, wrist or elbow.  Failing to do this may allow the cutter to run over the pattern and so fail to score the glass.

Alternatives to using the paper pattern directly as a guide in cutting glass are to outline the pattern paper on the glass with a pen or to draw the pattern on the glass while it overlays the drawing. You follow the inside edge of the pen line with the cutter.

Directly cutting the glass over the cartoon avoids the time spent in making patterns, and the difficulties and inaccuracies in multiple transfers of the shape. Often a light source is required under the cartoon to enable the lines to be seen through the glass. There will always be times when the glass is so dark or opalescent that the lines cannot be seen and therefore a pattern is required.

Keep the pattern cutting restricted to the times when nothing else will do.

The only times I use patterns for cutting are when the glass is too dense for the cartoon lines to be seen through the glass with light behind or for repeat shapes where a pattern can speed the process.

Two pattern pieces used to draw repeats of sails on the glass and then cut out

A boat design assembled in the kiln

 I draw around the pattern pieces, as that avoids the possibility of the cutter riding up on the card that I use for templates.  This comes from several occasions when the cutter did go over the template which prevented the score and so created a bad break.  Others do score around the template stuck to the glass successfully.

Where to Start Cuttng the Glass

As a general rule, always make the hardest cut first. Glass tends to run in a straight line. This means inside curves should be done before any other cut is made.

It will be most efficient to place the glass to be cut with the inside curve facing the raw edge of the glass. If something goes wrong, the glass can be backed away and tried again, resulting in less glass and time wasted.

It is also hard to run very thin strips of glass without getting ragged, chipped edges. Allow a 6mm minimum distance from the edge of the glass when placing the glass on the cartoon unless the edge glass is going to be used for the whole edge of the cut piece.

Prince Rupert's Drops

Though the underlying mechanism was not known at the time, the effects of "toughening/tempering" glass have been known for centuries. In the 1640's Prince Rupert of Bavaria, who was grandson of James I of England and VI of Scotland, and nephew of Charles I, brought the discovery of what are now known as "Prince Rupert's Drops" to the attention of the King. These are remarkable tear-drop shaped bits of glass which are produced by allowing a molten drop of glass to fall into a bucket of water, thereby rapidly cooling it. The resulting tear drop shape is very strong, resisting hammer blows. But breaking the tail causes the whole to shatter.

Chemical Compositions of Glass

Nearly all commercial glasses fall into one of six basic categories or types. These categories are based on chemical composition. Within each type, except for fused silica, there are numerous distinct compositions.

Soda-lime glass is the most common (90% of glass made), and least expensive form of glass. It usually contains 60-75% silica, 12-18% soda, 5-12% lime. Resistance to high temperatures and sudden changes of temperature are not good and resistance to corrosive chemicals is only fair.

Lead glass has a high percentage of lead oxide (at least 20% of the batch by weight). It is relatively soft, and its refractive index gives a brilliance that may be exploited by cutting. It is more expensive than soda-lime glass and is favoured for electrical applications because of its excellent electrical insulating properties. Thermometer tubing and art glass are also made from lead-alkali glass, commonly called lead glass. This glass will not withstand high temperatures or sudden changes in temperature.

Borosilicate glass is any silicate glass having at least 5% of boric oxide in its composition. It has high resistance to temperature change and chemical corrosion. Not quite as convenient to fabricate as either lime or lead glass. Borosilicate's cost is moderate when measured against its usefulness. Pipelines, light bulbs, photochromic glasses, sealed-beam headlights, laboratory ware, and bake ware are examples of borosilicate products.

Aluminosilicate glass has aluminum oxide in its composition. It is similar to borosilicate glass but it has greater chemical durability and can withstand higher operating temperatures. Compared to borosilicate, aluminosilicates are more difficult to fabricate. When coated with an electrically conductive film, aluminosilicate glass is used as resistors for electronic circuitry.

Ninety-six percent silica glass is a borosilicate glass, melted and formed by conventional means, then processed to remove almost all the non-silicate elements from the piece. By reheating to 1200°C the resulting pores are consolidated. This glass is resistant to heat shock up to 900°C.

Fused silica glass is pure silicon dioxide in the non-crystalline state. It is very difficult to fabricate, so it is the most expensive of all glasses. It can sustain operating temperatures up to 1200°C for short periods.


The full article is available from the Corning Museum of Glass

Baoli compatibility with Bullseye

My tests have shown a variety of compatibilities from badly incompatible to apparently fully compatible. Each sheet will need to be tested against Bullseye, but this gives some indication of the extent of compatibility across the range. With my set of samples this indicated that 71% might be compatible, 23% showed stress and 6% were clearly incompatible.

All these were tested using Bullseye Tekta 1101.38 with a strip test. Again I stress each sheet of Baoli will need to be tested before use.

BB00-3 compatible
BB001 slight incompatibility
BB023-3 not compatible
BB024-3 slight incompatibility
BB031-3 compatible
BB032-3 slight incompatibility
BB059-3 compatible
BB063-3 compatible
BB071-3 compatible
BB072-3 compatible
BB074-3 compatible
BB081-3 compatible
BB082-3 compatible
BB091-3 slight incompatibility
BB101-3 slight incompatibility
BB211-3 compatible
BB0311-3 compatible
BB0410-3 compatible
BB0411-3 compatible
BB0412-3 compatible
BB0413-3 slight incompatibility
BB0414-3 compatible
BB513-3 slight incompatibility
BB0413-3 compatible
BB0414-3 compatible
BB0415-3 compatible
BB0416-3 compatible
BB049-3 compatible
BB0510-3 compatible
BB0511-3 compatible
BB0512-3 compatible
BB0513-3 compatible
BB058-3 compatible
BB711-3 slight incompatibility
BB712-3 compatible
BB812-3 slight incompatibility
BB911-3 not compatible

Painting Tracing Lines on Glass

Testing the thickness of the paint
Using your smaller brush, load the paint into it, and practice applying black lines on a clear piece of scrap glass. If the paint seems too thick, add a very small amount of water.

Paint that does not stick
If the paint seems to bubble up or not adhere to portions of the glass, it is likely the glass is not clean. You can wash the glass, or simply add a little more water to the paint already on the glass and rub the paint over the glass with your finger or a small piece of paper towel. This will remove any dirt or film of oils on the glass.

Testing the amount of gum arabic
Allow your painted lines to completely dry. You will notice the dry paint has a chalky, opaque quality. Test your paint lines by rubbing a finger across a line. If it easily rubs off like powder, you need a bit more gum arabic. If you can't budge it and it seems hard and crusty, you have much too much gum in the mixture. Adjust the mixtures accordingly.

Inspecting the fired glass
When the glass is fired in the kiln, the paint (which is made of ground glass and various ground pigments) fuses with the glass. Too much gum in the mix, and the paint may bubble, sit on the surface, or do a few other ugly and unprofessional tricks to embarrass you. You have no choice but to start over with a new piece of glass. Getting the amount of gum arable right is crucial to the process.

If the lines are not consistent in colour depth, you can trace over them and fire again. This will darken the lines to a consistent level of colour.

Practice
Practice your tracing. This part of the art is like calligraphy - half the battle is learning to use your tool, the tracing brush, in one or two confident strokes. The quality of your trace line tells the world whether you are an amateur or an accomplished artist! You might even decide this is the only glass painting technique you will ever use. And you would be in good company. A good deal of Gothic stained glass relied solely on tracery for its embellishment and to good effect.

Coloured Glass

Glass is coloured by (1) impurities in the batch ingredients, or(2) by one of three processes:

a. using a dissolved metallic oxide to impart a colour throughout
b. forming a dispersion of some substance in a colloidal state, and
c. suspending particles of pigments to form opaque colours.

A few historical examples:
The name of a colour was often used to describe a certain kind of glass, as in the Black bottle: a term for bottles of dark green or dark brown glass, the dark colour of which protected the contents from light. Often the "colour" black that appeared with reflected light was caused by the combination of iron, found in the sand used to make the batch, and the sulphur found in the smoke from the coal used to melt the batch. "Black" glass was first made in England in the mid-17th century.

Often, the name of the mineral added to give the glass its colour, as in Uranium glass (glass coloured with uranium oxide) was used. This brilliant yellow-green glass was first made in the 1830s.

Sometimes, a combination of both the additive and colour, as in Gold ruby glass was used. This is a deep red glass coloured by the addition of gold chloride to the batch. The method of making gold ruby glass was perfected shortly before 1679.

Optical terms can be used to describe the glass, as in dichroic glass. This is glass that is one colour when seen by reflected light and another colour when light shines through it (this is sometimes due to the presence of minute amounts of colloidal gold).

Iridescent glass is a deliberate effect (visually similar to the shimmering rainbow effect seen on the surface of soap bubbles, oil slicks, or fish scales). This is achieved by the introduction of metallic substances into the batch or by spraying the surface with stannous chloride or lead chloride and reheating it in a reducing atmosphere. On ancient glass, iridescence is caused by interference effects of light reflected from several layers of weathering products.

Iron can produce greens, iron and sulphur can produce ambers and browns, copper can produce light blues, cobalt produces very dark blue, manganese can produce shades of amethyst colour, tin can produce white, lead antimony can produce yellow and various metals produce reddish glasses.

A decolorizer is a substance (such as manganese dioxide or cerium oxide) used to remove or offset the greenish or brownish colour in glass that results from iron impurities in the batch or iron or other impurities in the pot or elsewhere in the production process.

The full article can be seen at the Corning Museum of Glass

Copper Foil Splits

Copper foil splits often occur at tight inside curves. This is caused by the inability of the copper to stretch enough at the edges to make it around in tact.

There are at least two ways to deal with copper foil splits: avoid them or repair them.

Avoidance
One way to avoid splits at tight inside curves is to hand foil pieces that have these curves. When folding the foil from the edge to the sides of the glass, gently and progressively ease the foil toward the sides of the glass with your fingers rather than a hard tool. Do not try to make the fold all at once. Give the foil the chance to stretch into the curve through gentle persuasion.

Another way to avoid the splits is to use several short strips of foil at the tight inside curve. Apply each strip from one side around the edge to the other side of the glass. Overlap each strip until the inside curve is covered. Then you can cover the whole curve in the normal way with the copper foil. When the piece is foiled, you can then take a craft knife and trim the overlapped foils to match the edge of the long strip of foil. Or you can just trim the overlapped foil pieces to match the rest of the foil. Be aware that this increases the space required between the glass pieces as the foil is now effectively twice the thickness of regularly applied foil.

Repair

To repair splits in the foil at tight inside curves that have been foiled along with the rest of the piece, you take small pieces of foil and overlap at the splits.

Then trim the overlaps to match the line of the main foil. You can do this only on the surfaces or by going from one surface around the edge to the other surface.

When tinning these repairs, you need to take care that the heat from the iron does not loosen the adhesive so much that the foil pieces move.

Copper Foil Adhesive

The only technical purpose the adhesive on copper foil serves is to hold the foil on the glass until it is soldered. It is not intended to, and will not hold the piece together. You shouldn't ever rely on it to hold the pieces together. The heat from the soldering breaks down the adhesive, as well as time and chemicals like glass cleaner and flux. If you think that burnishing it harder will seal it, you are mistaken.If your foil is pulling away from an edge, you need to build up the solder on the edge, add wire if necessary, or a perimeter metal of some sort.

If you have a piece of glass that is "slipping" out, you may be trying to hold up too much weight by the foil. Put a perimeter metal on and hang the piece from a solder joint that extends into the design.

Soldering Copper Foil

Tip size
Soldering copper foil is ideally done with a smaller tip than for leaded glass. A 3/16" long taper tip is useful. Use the tip on edge rather than the flat side in order to minimize the iron's contact with the glass. Thus, the iron is held almost vertical. Foil heats up very fast and too much heat can crack the glass so the narrower the iron contact is the lower the risk.

Solder application
The solder is applied in one of two ways. The quickest method is to feed solder in on the thicker part of the shiny tip and let it flow down to the foil. The iron is held against the foil and pulled along the foil (which has been fluxed) at the rate that allows the solder being fed to the iron to produce a slightly rounded, shiny solder bead. Don't try and "float" the iron on top of the solder, be firmly down against the foil. This requires practice to match the speed of movement and the amount of solder fed to the iron.

Alternatively, you can do the patting method. This is easier to control and is done by soldering one tip-length, lifting the iron and soldering the next tip-length, barely re-heating the section just soldered.

Another variation is to place blobs of solder at regular intervals along the foiled and fluxed joint and then move the iron along the joint melting the blobs as you go. This avoids the tide marks at the cooling ends of the solder bead.

Reinforcement Materials and Methods

Variations in Reinforcement Materials and Methods

Be aware that every reinforcement situation is likely to vary. This is even more prevalent today with stained glass being more utilised in conditions which present varied structural situations.

External steel bars
There are many methods employed to provide reinforcement and a variety of mounting procedures. Surface reinforcement is probably best accomplished with flat cold-rolled galvanized steel bars either 3/8" or 1/2" in width by 1/8" thick. Since they are directly affixed to the solder joints of the section they disperse greater reinforcement than with 14 gauge copper tie wires attached to round or square bars which tend to stretch and consequently result in buckling from the sagging of the section.

Steels
Internal flat steel bars incorporated within the heart of the came are also of excellent service, especially in vertical instances. Horizontally they provide lateral reinforcement but likely no vertical resistance to sag.

Saddle bars
These are normally round or square steel bars that span the opening. The panel is inserted into the opening and blocked into place. The saddle bars are placed in the slots prepared in the sides or top and bottom of the opening, and the copper ties already soldered to the panel’s joints are twisted round the bar.

T bars
These are “T” shaped bars attached to the sides of the opening with the leg of the “T” facing outwards, The panel is supported by resting on the horizontal portion of the “T”. It is then fixed into place and cemented. These bars are normally made of alloys that do not corrode easily.

The Negotiating Framework for an Exhibition, 3

Proposals and Agreement

Make a proposal
Once you've had a chance to assess each other's position, you're ready for proposals and suggestions to be made. Mindful of how you have prioritised your list of 'achievements' you can start to 'trade', all the time looking for opportunities to offer things that are 'cheap' for one party but that are of real value to the other.
For example, a local authority or academic gallery that has an in-house photographer could offer the artist high-quality visual documentation of their exhibition that would otherwise cost the artist large amounts. An artist may offer to recommend the gallery as a good venue to peer artists in other areas or countries, to support the gallery's 'talent spotting' aspirations.

Trading and bargaining
After this period of exploration and testing, the trading and bargaining begins in earnest. Don't assume however, that this all has to happen at once, as you may do the testing and proposal-making some weeks or days before you sit down to bargain and finalise the arrangement. In general terms, ask for more than you expect to get and don't concede too much at the beginning because you've reduced your subsequent bargaining 'chips'.

In face-to-face discussions, be aware that body language speaks volumes - leaning back and folding your arms sends a signal that you're 'closed to discussion', whilst keeping eye contact and maintaining a normal sitting position says the reverse. It is an important to listen actively, to concentrate on what the other party is saying rather than waiting for them to finish so you can jump in and make your own points. Don't always feel obliged to bring in 'new' material when you speak, you can instead summarise what has been discussed as a way of 'buying time' to decide your next move. Silence is OK too, providing time to gather thoughts for another intervention.

Nowadays, negotiation is often done via email or telephone. It's better to avoid making curt or aggressive comments that can tend to turn a collaborative negotiation into a confrontational one. Don't reply to emails or unexpected telephone calls 'off the cuff'. Always refer to the paperwork or notes from previous communications.

An agreement cannot be reached until the parties get to a position they can both 'live with'. As a matter of course, this is generally somewhere between their respective starting points. Neither party should afterwards feel they were 'backed into a corner' or browbeaten into finalising the negotiation. If someone is pressing you to agree now it's usually because they will get more out of the arrangement than you will. So best not to.

When you've reached an agreement, write up your notes as a letter noting all the areas of agreement and send to the other party, asking them to confirm by signing, dating and returning to you a second copy that you have provided. Either artist or exhibition organiser can write up the agreement.

Susan Jones (used with permission)

The Negotiating Framework for an Exhibition, 2

Beginnings

The opening
The first phase of a collaborative negotiation on an exhibition involves gathering as much information as possible, preferably well in advance of any meeting.

• Artists - research the gallery, how it programmes, what its current interests are, which other galleries 'look to' that one because they are good at picking interesting artists, etc.
• Gallery - research the artist, the context for their work, their peer network, their other projects, etc.

What do you want to achieve?
Before you start a negotiation, set out for yourself on paper what you want to achieve from the exhibition opportunity in terms of:

• Things you must achieve
• Things you intend to achieve
• Things you'd like to achieve

Discuss and explore
The first meeting provides an opportunity for artists and exhibition organiser to explore each other's needs, start to create a relationship and as part of this, for each to make tentative offers. Avoid stating your own preferences and ideas and instead use 'open questions' that create a space in which ideas can be explored, for example:

• What do you think about...?
• Is there something you'd like to suggest?
• From your experience, what do you find works well...?
• What other options could we look at?

Susan Jones (used with permission)

The Negotiating Framework for an Exhibition, 1

Introduction
In the world outside the arts, when someone offers something - a house for sale, a job, work from a trades person, a proposal of marriage even. This is generally the opening gambit in a negotiation process by which what has been offered will be discussed and in the process, either adjusted to create something of mutual benefit, or declined. But in the visual arts there is a tendency for the offer of an exhibition by a gallery to an artist to be taken at face value and either accepted or rejected. This doesn’t need to be so.

The intention here is to set out a mechanism for a collaborative negotiation. Through this the artist and gallery can share their respective aspirations and intentions for a proposed exhibition, and negotiate in order to arrive at a 'win-win' situation. One in which both feel comfortable about what has been agreed because they will both benefit. Importantly, they have also created a working relationship that can be built on in the future.
A collaborative negotiation is preferable to a competitive one where the parties are essentially out to get the best for themselves regardless of the wider implications. An unhappy relationship between artist and gallery tends to ricochet around the art world and does neither any good in the longer term.

Anyone inexperienced in negotiation techniques should get some professional guidance in advance. Artists could do this by contacting a training or professional development organisation. An arts organiser might ask for coaching from a line manager or senior colleague.

Susan Jones (used with permission)