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.
Thursday, 12 March 2009
Wednesday, 11 March 2009
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.
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.
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.
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.
Tuesday, 10 March 2009
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.
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.
Monday, 9 March 2009
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
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
Friday, 6 March 2009
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.
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.
Thursday, 5 March 2009
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.
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.
Wednesday, 4 March 2009
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.
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.
Tuesday, 3 March 2009
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.
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.
Monday, 2 March 2009
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.
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.
Friday, 27 February 2009
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.
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.
Wednesday, 25 February 2009
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.
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.
Monday, 23 February 2009
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.
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.
Friday, 20 February 2009
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.
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.
Thursday, 19 February 2009
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
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
Note
If the score line is further than 20mm away from the edge, cut running pliers are the appropriate tool to use.
Wednesday, 18 February 2009
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.
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.
Tuesday, 17 February 2009
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.
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.
Monday, 16 February 2009
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
Glass strongly resists electric current. It stores electricity very efficiently.
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.
Glass strongly resists electric current. It stores electricity very efficiently.
Friday, 13 February 2009
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.
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.
Tuesday, 10 February 2009
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.
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.
Monday, 9 February 2009
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.
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.
Friday, 6 February 2009
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.
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.
Thursday, 5 February 2009
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.
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.
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.
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| Two pattern pieces used to draw repeats of sails on the glass and then cut out |
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| A boat design assembled in the kiln |
Wednesday, 4 February 2009
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.
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.
Tuesday, 3 February 2009
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.
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