Soldering Bit Maintenance - Wiping the Bit

During use a bright, thin, but evenly tinned surface must be maintained on the working portion of the bit. Oxidation and contaminants must be continually removed from the bit surface to achieve maximum performance. This will help to ensure the proper transfer of heat from bit to work and will eliminate the possibility of impurities being transferred into the solder joint.

Between each solder application simply wipe the working area of the bit clean on a damp cellulose sponge to remove the dross and oxides that will accumulate and add small amounts of fresh solder to the bit as needed. A gentle wiping is all that is required and care must be taken not to over wipe the bit, because oxidation will occur on the surface quite rapidly if all of the solder has been removed. Once this oxidation occurs it becomes difficult, or even impossible for solder to wet to the bit. It then becomes necessary to properly clean and re-tin the bit in order to regain the appropriate wetting action required for adequate performance. When you have finished the soldering application, you should wipe any contaminates from the bits surface and add a small amount of fresh solder to it before allowing the iron to cool. This layer of solder ensures protection from oxidation of the bit between uses and will help to extend the bits working life.

Courtesy of American Beauty Tools

Other links to Soldering Iron Maintenance:
https://glasstips.blogspot.com/2019/11/soldering-iron-maintenance.html

https://glasstips.blogspot.com/2010/01/maintenance-of-soldering-bits-periodic.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-wiping-bit.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-tinning.html

Soldering Bit Maintenance - Tinning

Introduction
Proper care and maintenance of your soldering iron bit involves tinning, wiping (and wetting) and also periodic cleaning of the bits shank. These actions are very important and quite simple to perform, but are often neglected. When performed properly they will not only ensure the longest possible working life for your soldering iron bits, but they will also have positive effects on the overall performance of your soldering iron.

TinningTinning may not be necessary if the bit you are using is new and arrives pre-tinned from the manufacturer, or has been used previously and been properly maintained. When a bit does need to be tinned (or re-tinned) it must be clean and free of any surface oxidation before it will accept any solder. Once the bit is properly tinned, care should be taken to prevent bit de-wetting by occasionally cleaning and adding small amounts of fresh solder, especially if the bit is being subjected to long periods of inactivity or idling.

If the bit to be tinned is un-plated copper it should be cleaned and dressed with a single cut, flat file. After filing the bit it should be heated in the iron. When the bit reaches the lowest temperature required to melt solder, a rosin core solder should be fed onto the bit. Do not allow the iron temperature to rise too high before applying the solder, because excess heat will cause the bit surface to re-oxidize and no longer accept the solder.

If the bit is plated it should never be filed, or heavily abraded. Care should be taken to ensure the plating is not damaged or removed, as this will shorten the working life of the bit dramatically. When pre-cleaning is necessary for plated bits, they should be cleaned with a mildly abrasive emery cloth and may require an acid flux to remove the oxides before tinning, or re-tinning.

Courtesy of American Beauty Tools

Other links to Soldering Iron Maintenance:
https://glasstips.blogspot.com/2019/11/soldering-iron-maintenance.html

https://glasstips.blogspot.com/2010/01/maintenance-of-soldering-bits-periodic.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-wiping-bit.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-tinning.html

Soldering Bit Maintenance - Summary

If a bit has not been properly tinned, solder will not wet to it. Without solder on the bit heat transfer from the bit to the work surface may become extremely difficult and time consuming, or even impossible.

You must understand that proper wiping and continuous wetting is important and a lot easier than continually having to clean and re-tin the bit, especially at the risk of damage to the plated surface because of accidentally scratching, or over abrading it.

When you notice that an iron is not performing as well as it did when it was new you will find that poor thermal transfer from the element to the work is usually the cause. Improper care and maintenance and the lack of a periodic cleaning of the bits shank can cause a layer of oxides, which will inhibit the transfer of heat through the bit. Always ensure plug style bits are properly seated into the elements before heating the iron. If a bit is not inserted fully into the element there may be a gap behind the bit. This gap can cause a hot spot within the element causing a premature failure of the soldering iron.

Courtesy of American Beauty Tools


Other links to Soldering Iron Maintenance:
https://glasstips.blogspot.com/2019/11/soldering-iron-maintenance.html

https://glasstips.blogspot.com/2010/01/maintenance-of-soldering-bits-periodic.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-wiping-bit.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-tinning.html

Choosing the Soldering Bit

An important consideration, when choosing the most appropriate bit, is that thick, short bits will store more heat and deliver it more efficiently than long, narrow ones. This makes the standard chisel configuration the usual bit of choice. The chisel shaped bit is often used for joining flat seems together. The working edge of the chisel bit should be about the same width as (or slightly wider than) the seam that is being soldered.

Usually a solder connection is made in one to three seconds. If the connection takes longer than three seconds, you may need a larger bit, a higher wattage iron or a completely different type of soldering equipment altogether. It is a good idea to familiarize yourself with other soldering methods and equipment that are available in order to ensure that you are utilizing the best, safest, most efficient and economical means available to perform your soldering application.

Courtesy of American Beauty Tools

Soldering Bits

Type
The bit type is determined by the soldering iron it is used on. There are screw type bits (bits that screw onto, or into the solder iron element), slip on bits that slip over the element and plug type bits that slide inside of the element. There are even bits that are a permanent part of a replaceable element/bit assembly. Regardless of the type of bits required it is always important to have them fully seated to the element and periodically cleaned, in order to maintain proper heat transfer from the element into the bit.

ConfigurationThe bit configuration to use should be determined by the intended application requirements. Some of the basic bit configurations available include ballpoint, conical, diamond (pyramid), chisel, and spade. You will find that there are usually a variety of styles, or modifications available, within each of these basic configuration families, to accommodate specific application requirements. Although less efficient, a more narrow configuration is sometimes required to obtain accessibility, or to achieve the desired results.

SizeThe bit size to use (regarding the working portion) should also be determined by the intended application requirements. The bit body, or shank must be matched to the iron it will be used with (always select a bit that was designed, or approved for the soldering iron you intend to use on the application being considered). As with bit configuration though, there are usually a variety of modified working diameters available within each family of standard bit sizes that are available. These modified bits are generally referred to as turned down bits, because the working area of the bit has been turned down to a smaller diameter than the body, or shank diameter. Turned down bits are not as efficient, but are sometimes required to solder in otherwise inaccessible areas.

Courtesy American Beauty Tools

Tack Soldering

Tack soldering is the placing of a small amount of solder on the foil to hold two or more pieces together, so the main soldering can be performed without disturbing any placing of the remaining pieces.


The advantage of tack soldering is it can allow you to completely eliminate framing. You can just hold two pieces together with one hand and spot a dab of solder to hold them together. You don't have to do this for all pieces - just enough of the outside pieces to hold the whole project together. Once you've tack soldered, everything will be held in place and you can just run the beads without further considering the placing of the pieces.

For free form shapes, tack soldering is always quicker. You may want to use nails or tacks to hold all the glass in place while you tack solder.

With big foil projects or ones that have to fit into a predetermined dimension, tack soldering ensures there is no growth through movement of the pieces.

It's a quick way to avoid having to fiddle with each piece to make sure each is exactly lined up before starting with the running of the beads.

Soldering Bit Composition

Most bits are made of copper, which is suitable because of its excellent thermal conductivity and high heat content per volume. Some bits are plain copper, while others incorporate various additives or have a protective plating applied.

One of the most common problems associated with plain copper bits, is that tin-lead alloys (more specifically the tin in the alloy) will attack the copper, dissolving it away. This makes it necessary to continually file the bits to maintain the required shape, giving these bits a shortened working life. Another concern is the amount of impurity that is imparted to the solder joint when using bare copper bits.

Adding tellurium to the copper improves both wear and oxidation resistance, but does not protect the tip from rapid deterioration. It has been determined that both iron and nickel, despite their low conductivity, are wettable, offer a high level of resistance to erosion and their heat per volume is close to that of copper.

Because of these facts it is possible to maintain good conductivity, while increasing the erosion resistance by plating copper bits with either nickel or iron. These plated bits are generally referred to as nickel-clad, or iron-clad and make up a large majority of the bits in use for modern soldering applications.

Courtesy of American Beauty Tools

Even Solder Beads on Edges

Running an even bead on the edges of copper foiled projects is often difficult. Several things can help.

Hold the panel vertically and ensure the edge you are applying solder to is horizontal. This means that you have to keep moving anything that is not rectangular.

To apply solder and move the piece ideally needs three hands – one for the solder, one for the iron, and one to manipulate the piece. Failing such an evolutionary leap, you can use a small vice to continually alter the angle of the edge, you can get a friend or colleague to manipulate the panel, or you can place the solder so that you can pick up little drops of solder and place them on the edge. With practice, you can pick up some solder and transfer it to the edge before the previous dot of solder has cooled, so leaving a smooth bead by the joining of the dots.

Alternatively, you can place dots of solder near each other around the piece. You then come back and with one hand manipulating the piece the other can use the solderimg iron to heat and join the dots.

You do have to be careful that you do not move the panel before the solder has hardened, or it will run down the newly created slope to the new horizontal edge.

I find that it is much more difficult to run a bead on an edge than it is to “pat” the solder dots. This patting motion allows the solder to join together, but does not heat such a long line that it flows as you turn the piece to keep the edge currently being soldered horizontal.

Even Solder Beads

Getting even solder beads is a lot about where you look while you solder. Unlike drawing or cycling looking at where you are going is not so useful when soldering. You need to see the effects of what you are doing so looking behind the solder bit will help you understand what you are doing. If the bead begins to get small or narrow you either slow down the forward movement of the solder bit or add solder to it more quickly. If the bead begins to get too thick, you do the opposite. You can move the bit faster, or reduce the speed of feeding the solder to the bit.

Another element in getting an even bead is the heat being delivered. If you use a wide soldering bit you are delivering more heat to the joint. You hold the chisel bit so that it runs along the foil. The bigger the bit, the more heat is being held. And the more heat held in the bit, the more heat is applied to the soldering. Small bits are for getting into tight spots and for decorative soldering. Big wide bits are best for running beads.

Plaster Properties - Effect of Plaster-Water Ratio

Plaster-water ratio (by weight) of 100 plaster to 30 water gives:
a setting time of 1.75 mins,
a compression strength of 813 kg/sq cm., and
a density of 1806 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 40 water gives
a setting time of 3.25 mins,
a compression strength of 477 kg/sq cm., and
a density of 1548 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 50 water gives
a setting time of 5.25 mins,
a compression strength of 318 kg/sq cm., and
a density of 1352 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 60 water gives
a setting time of 7.24 mins,
a compression strength of 230kg/sq cm., and
a density of 1207 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 70 water gives
a setting time of 8.75 mins,
a compression strength of 176 kg/sq cm., and
a density of 1083 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 80 water gives
a setting time of 10.5 mins,
a compression strength of 127 kg/sq cm., and
a density of 990 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 90 water gives
a setting time of 12 mins,
a compression strength of 99 kg/sq cm., and
a density of 908 kg/cubic metre

Plaster-water ratio (by weight) of 100 plaster to 100 water gives
a setting time of 13.75 mins,
a compression strength of 70 kg/sq cm., and
a density of 867 kg/cubic metre

Properties of Typical Gypsum Plasters and Cements

No. 1 pottery plaster
Water to be added as % of dry mix by weight - 70%
Setting time - 27-37 mins
Dry density (kg/cubic metre) - 1106
% expansion on setting - 0.21
Compressive strength (kg/sq cm) - 127.26


No. 1 molding plaster
Water to be added as % of dry mix by weight - 70%
Setting time - 27-37 mins
Dry density (kg/cubic metre) - 1106
% expansion on setting - 0.20
Compressive strength (kg/sq cm) - 141

Plaster of Paris
Water to be added as % of dry mix by weight - 70%
Setting time - 27-37 mins
Dry density (kg/cubic metre) - 1106
% expansion on setting - 0.20
Compressive strength (kg/sq cm) - 141

No. 1 Casting plaster
Water to be added as % of dry mix by weight - 65%
Setting time - 27-37 mins
Dry density (kg/cubic metre) - 1162
% expansion on setting - 0.22
Compressive strength (kg/sq cm) - 170

Pottery plaster
Water to be added as % of dry mix by weight - 74%
Setting time - 27-37 mins
Dry density (kg/cubic metre) - 1057
% expansion on setting - 0.19
Compressive strength (kg/sq cm) - 127

Hydrocal cement
Water to be added as % of dry mix by weight - 45%
Setting time - 25-35 mins
Dry density (kg/cubic metre) - 1442
% expansion on setting - 0.39
Compressive strength (kg/sq cm) - 35

Hydroperm cement
Water to be added as % of dry mix by weight - 10%
Setting time - 12-19 mins
Dry density (kg/cubic metre) - <641
% expansion on setting - 0.14
Compressive strength (kg/sq cm) -


Hydro-Stone cement
Water to be added as % of dry mix by weight - 32%
Setting time - 17-20 mins
Dry density (kg/cubic metre) - 1914
% expansion on setting - 0.24
Compressive strength (kg/sq cm) - 707

Ultracal cement (30)
Water to be added as % of dry mix by weight - 38%
Setting time - 25-35 mins
Dry density (kg/cubic metre) - 1588
% expansion on setting - 0.08
Compressive strength (kg/sq cm) - 424

Solarisation

Old glass can show changes in colour as evidenced by the different colour of the glass under the lead came where the light cannot reach the glass.

Drew Anderson has provided the explanation.

This change in color of some glass is known as solarisation.

The main ingredient of most glasses is silica, which is usually introduced as a raw material in the form of sand. Silica itself is colorless in glass form but most sands contain iron as an impurity, and this gives a greenish tint to glass. By adding certain other ingredients to a molten glass, it is possible to change the greenish color and produce colorless glass.

These ingredients are known as decolorizers, and one of the most common is manganese dioxide (MnO2). In chemical terms, the manganese acts as an oxidizing agent and converts the iron from its reduced state - which is a strong greenish blue colorant - to an oxidized state which has a yellowish, but much less intense, color. In the course of the chemical reaction, the manganese goes into a chemically reduced state, which is virtually colorless.

When pieces of decolorized glass containing reduced manganese are exposed to ultraviolet radiation for long periods of time, the manganese may become photo-oxidized. This converts it back into an oxidized form. Even in low concentrations this imparts a pink or purplish color to glass. The ultraviolet rays of the sun can promote this process over a matter of a few years or decades.

Selenium and cerium have also occasionally been used as a decoloriser and can produce solarisation colors, just as manganese does. The colors developed by these two elements are said to range from yellow to amber.

Mesh Sizes from a Typical Manufacturer

Mesh sizes have traditionally been measured by the number of wires per square inch used to sieve the material. This table gives a grit size measurement for the mesh/grit numbers in common use.

Mesh = Mesh opening (mm)
12 =   1.5240
14 =   1.2954
20 =   0.8636
30 =   0.5156
40 =   0.3810
50 =   0.2794
60 =   0.2337
80 =   0.1778
100 = 0.1397
120 = 0.1168
200 = 0.0737
325 = 0.0432
400 = 0.037
625 = 0.020
1200=0.012
2500=0.005

Break-Down Temperature of Common Mould Binders

The temperatures that various binders used in mould making is important to consider, as once they reach the break down point, they lose their strength and therefore ability to hold the mould together. The following table gives some indication of the characteristics of various binders.

Binders and Break-down Temperatures (degrees C)
Gypsum plaster - 704 - 816
Hydrocal cement - 704 - 816
Hydroperm cement - 760 - 927
Colloidal silica - 1260
Colloidal alumina - 1260
Calcium alumina (ciment fondu) - 1538

These of course, are not the only considerations in mould making but do show why combinations of materials is important. The common plasters and cement break down before the casting temperature of glass, typically 850C.

Polishing 3D Glass on a Wet Belt Sander

Polishing three dimensional objects depends on the shape of the glass you are sanding down to the polished surface.

Convex shapes can be done on the wet belt sander with ease.

You can polish slightly concave items on a belt sander if you have an unsupported section of the belt. On machines with a flat platen, you can remove the platen to use the ability of the belt to form into a slightly convex curve.

Removing silicone

To remove silicone before it is cured you use a putty or other straight bladed knife to remove any of the uncured paste. Then wipe the area clean with isopropyl alcohol to remove any leftover residue.


After it is cured you should first you should 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.

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. Material Safety Data sheets are available upon request from manufacturers. Similar information for solvents and other chemicals can be obtained from manufacturers.

There also are “Silicone Eaters” on the market now. The chemical composition is unknown, but are less messy and more expensive than some of the other solvents. Use according to instructions.

Glass Polishing Machines - Linisher

A wet belt sander, or linisher, is a machine intended to grind the edges of flat pieces of glass. It can do some work on bent, shaped, or slumped work, but its primary function is edging work while it is flat.

Table top model

The machines consist of a vertical or near vertical belt and a water supply to keep the belt and work lubricated and cool. Work generally starts with a low numbered grit belt, perhaps 80 grit, and then proceeds through the higher numbers. For example: 80, 120, 220, 400, 600, cork. Each stage should approximately half the grit of the previous one.

Floor standing model

Even with a cork belt, don’t expect a gloss you would see from a fire-polished piece. For that you need a cerium oxide belt or a felt belt with cerium oxide paste. Trizact is a brand name for fine polishing belts not requiring cerium oxide paste. These may be substituted for the more messy paste methods.

You can buy silicon carbide or diamond belts for a wet belt sander. The diamond belts are very expensive, but much longer lasting with proper care. If your belts are likely to receive rough treatment stick with the cheaper silicon carbide belts.

Cooling Events

This is based on Graham Stone’s work with float glass. The temperatures are applicable to float glass, and so need to be adjusted for a particular glass, but illustrate the principle of how heating temperatures affect the glass. Temperatures in degrees Celsius.


600 Common temperature for crash cooling toward. Glass beginning to "freeze".

555 Annealing temperature of float. Bungs in.

515 Approximate Strain Point of float.

535-400 Critical slow cooling down phase for float that overlaps annealing range.

400-300 Medium cooling down ramp rate.

300-10 Fast cooling down ramp rate. Cracking the kiln open possible.



Based on Firing Schedules for Glass; the Kiln Compainion, by Graham Stone, Melbourne, 2000, ISBN 0-646-39733-8, p24

Casting Temperature Events

This is based on Graham Stone’s work.
Temperatures are in degrees Celsius.

660 Bungs still out for casting.

710 Mould "curing" starts (molecular moisture being expelled).

820 Bas relief complete. Whiting gives off CO2

850 Glass flowing. Viscosity decreasing quickly. Common casting temperature

870 Fine mould/mold detail complete

900 Plaster moulds becoming very brittle

950 Un-reinforced plaster moulds no longer viable.

1100 Glass runny enough for sand casting and other manipulative techniques.


Based on Firing Schedules for Glass; the Kiln Companion, by Graham Stone, Melbourne, 2000, ISBN 0-646-39733-8, p24

Disposal of Used Bullseye Thinfire

The main ingredients of Bullseye’s Thinfire are cellulose, aluminum hydroxide, fiber glass, and organic binders. It is predominately a nuisance dust and irritant.

Use a vacuum sweeper with a high efficiency filter and a bag rated for plaster dust. Also many vacuums with a HEPA filter system will be sufficient. Wrap the disposable bag in another -preferably paper - bag to avoid dispersing the dust when it goes into the rubbish.

Viscosity Changes with Temperature

This is based on Graham Stone’s work with float glass. The temperatures are applicable to float glass, but illustrate the principle of how viscosity changes in a non linear pattern with the increase in temperature. Temperatures are in degrees Celsius.

515 Viscosity 10145 poises (approximate strain point of float)
555 Viscosity 1013 poises
610 Viscosity 1010 poises
730 Viscosity 976 poises
850 Viscosity decreasing faster
900 Viscosity now 105 poises and falling

Based on Firing Schedules for Glass; the Kiln Companion, by Graham Stone, Melbourne, 2000, ISBN 0-646-39733-8, p24.

This shows that viscosity changes rapidly from the lower strain point (the solidification of glass) to annealing.  The change slows from the annealing point to full fusing, but changes rapidly after that.  This is an important factor to control in casting and free drops.

What is viscosity
Graph of the changes

Paint – Temperature Effects

This is based on Graham Stone’s work with float glass. The temperatures are applicable to float glass, and so need to be adjusted for other glasses, usually a bit lower. But these temperatures illustrate the principle of how heating temperatures affect the paints. The temperatures will need to be adjusted when fired on other glasses than float. Temperatures are given in degrees Celsius.

570 Low firing glass enamels fired
650 Silver stain fired.
690 Low fire red enamel burnout.
730 "Paradise" paints fired.
750 Onglazes fired.
800 Lustre burnout begins.

Based on Firing Schedules for Glass; the Kiln Companion, by Graham Stone, Melbourne, 2000, ISBN 0-646-39733-8, p24

Iridised Side of Glass

It can be challenging to determine the iridised side of glass. The coating is very thin and so cannot be seen by looking at the edge. There are several ways of testing for the coated side. Two that I find useful are:

The pencil test – In this you put a pencil point or other point to the glass. You then look for the reflection at an acute angle to the glass. If there is a gap between the point and the apparent surface of the glass, the coating is on the other side. And in reverse, if the point is immediately reflected with no gap, the point is touching the coated side.

Another test is the fingernail test. If you have sensitive nails, you can feel the difference in surfaces by gently dragging your nails at an almost right angle to the glass. The rougher side is the coated one.

There are other tests but these two work for me.

Foil Lifting While Soldering

There are several possible reasons for this.

The main one is that the soldering is too slow. This causes the adhesive on the foil to fail before the solder has a chance to become rigid.

The foil may not have stuck to the glass firmly. Reasons for this are many, but some are:

- Dirty glass. Make sure the glass is washed and polished clean, especially if you have been grinding, when you need to get all the glass dust out of the pits on the edges.
- Oils from your hands. The oils can be natural or from hand creams. If you have oily skin or need to use hand creams consider cotton gloves for use when handling the glass prior to and during foiling.
- Inadequate contact between the foil and the glass. This can be from both the above, but can also be that the foil was not pressed firmly to all the sides and edges of the glass pieces.


The foil adhesive may be inadequate through manufacture or age. If a test piece does not feel tacky to your finger tips, it is not going to stick to the glass very well.

Grinding for Copper Foil

It is often thought that every piece of glass has to be ground to enable the foil to stick well to it. There are conflicting views about this. I am firmly on the side of not grinding. The impact adhesive on the back of the foil is thin and will not fill the depressions caused by grinding. It will adhere to a smooth surface more strongly than a rough one. Remember the purpose of the foil is to provide a surface to carry the solder. It keeps the foil in place until the solder bead is completed on both sides. It is not a permanent adhesive. So some of the discussion about which surface is best is academic.

There are ways of obtaining clean cuts that help avoid the need to grind.

Score with an even pressure. This helps the glass break clean with few shells or chips. If there are any overhangs, you can eliminate them with a quick wipe of the edge of the cut piece on the waste piece.

Ensure you hold your cutter vertically. This will encourage the break to be at right angles to the surface giving a clean smooth cut face.


The only NEED for grinding is to adjust an inaccurate cut. We all make inaccurate cuts from time to time.

Copper Foil Oxidisation

Protection of foiled pieces from oxidisation

If foiled pieces are going to sit a while before soldering, put them in a sealed plastic bag with the air squeezed out. This will prolong the time before the oxidization becomes a problem for the soldering process.

Another possibility is to tin all the pieces before putting them away in the plastic bag. Solder oxidizes more slowly than copper does.

Transparency Sketches

Use matt finish acetate .25 to .12mm thick. This will later be fixed to Perspex for presentation.

You will need rigger brushes in sizes 0, 1, 2, and 4 for doing the lead lines and other areas of graphic delineation. In using these brushes for lead lines, you want to maintain a line that is consistently thick. It is a different feeling from general image making and you may want to try locking your wrist to maintain a greater consistency of pressure.The paint for the lead lines can be a calligraphy ink or a black acrylic paint. The lead lines and all other tracing is applied to the matt side of the acetate.

Once the tracing lines are all completed, start laying the colours on the backside, the smooth side. The brushes to use are bulbous pointed sables in sizes 2, 3, 5 and 6. The application is in a "floated" versus a "stroked" manner of application. Stroking has a tendency to hasten the drying resulting in streaking. You may find this a bit of a trick at first. It is advisable to place colour throughout the design so it has time to set up and dry a bit, as opposed to putting wet against wet.

When the colour has dried, one can emulate matting on the matt side with an ebony pencil. And if you want to take out some lights, that can be accomplished with carefully placed extender. The extender is also used to make the piece transparent and to emulate a variety of textures available in glass from reamy to seedy.

When the colours are dry, mount the sketch on 3mm Perspex to stiffen the presentation, provide weight and give the presentation with some "substance”. You can also add double matt board doors hinged with smooth electrical tape to keep the lacquer colours away from sustained sun. Also when open, they support the sketch during the presentation.

When putting matting boards around the presentation sketch, they should be much wider than a drawing or water colour so that ambient light from behind is modified by a greater expanse of black or dark matting board.

Edited from emails by Richard Millard

Oxidized Copper Foiled Pieces

If copper foiled pieces sit out for any length of time after foiling they will oxidize. This means that the solder will not stick to the foil, as it requires a clean surface to attach to.

Clean the foiled pieces with fine steel wool, pot scrubber or flexible mild abrasive. Make sure you do not damage the foil or pull it up from the glass during this process. It is likely that the adhesive holding the foil to the glass is not as strong as it once was.

I do not recommend using a stronger flux to overcome the oxidisation, as this is often highly acidic and may damage the glass.

Once cleaned, you can flux the foil and proceed as normal.

Weaving in Leaded Glass

"Weaving" is only easily and fully done where there is a grid. The example below shows a restoration project where the main part of the panel is a grid.

This image shows the starting of the weaving. A short lead covering only one quarry has been placed horizontally - although you can start with a short vertical, both are fine. The next lead is vertical and covers two of the quarries. As you can see here the two quarries at the right are ready for the longer horizontal to be placed.




You proceed in this fashion - alternating long and short leads throughout the grid area.

As you can see this builds up in a diagonal fashion with each vertical and horizontal line being interrupted after every second piece of glass.

If you look closely you can also see that these leads are being tucked. This is easier with leads of 7mm and greater than of 6mm and less.

This method of leading gets its name from the similarity to representations of weaving in illustrations where a broken line represents the thread or reed going under another. Its purpose is to avoid hinges and so strengthen the whole panel. This avoidance of hinges makes the turning of the panel during soldering and cementing much easier.

Of course, you must remember that the glass is the strongest part of the panel.

Direct or Trace cutting

Place the glass over the pattern and run the cutter along the pattern lines you see by looking through the glass. There's no need to draw lines on the glass. For translucent glass you may need a light box.

You should be aiming to cut glass efficiently and accurately. Trace cutting is the most efficient, as it completes in a single operation what other methods –such as drawing on the glass or making templates from the cartoon - take several steps to accomplish.

It is more accurate because each extra step required for other methods increases the possibility for error. The fewer times you copy the original pattern lines, the less likely you are to diverge from the original pattern lines.

It is very important to keep the cutter at right angles to the glass - as seen from side to side, not vertical.  This of course is true of all cutting.  It makes the cutting inaccurate, because the light is bent when coming through the glass much like water changes the apparent angle of sight into its depths.  Tilted cutters also have undesirable effects when breaking the glass.

Tinning brass vase caps

Tinning brass vase caps can help in obtaining a secure joint without long dwells at each joint that risk overheating the glass.

Heat your vase cap with a torch of one kind or another. You can heat until it becomes a dull red. The quickly brush or rub (with a cloth) flux onto the inside and outside of the rim of the vase cap. Apply a little solder to the fluxed area while everything is still hot. This will tin all the areas where the flux was placed.

This method will give a strong solder to solder joint that requires much less time when soldering the cap to the rest of the lamp shade.

Leaded Glass Reinforcements

I received a query recently about this subject. As the correspondence may be useful to a more general audience, I present an edited version here. (all the personal chat has been taken out!)

“I was wondering if I would be able to ask you a question regarding re-enforcements. In regards to the hollow lead with the bar running through or using Reforce with the brass molded through it. Which is better?”

The lead covered steel is stronger. It has the disadvantage that if it gets moisture into it, it will corrode. Steel expands when it corrodes. This leads to progressive destruction of the surrounding glass.

Brass is weaker, but does not have the same degree of expansion when corroding.

Steel is cheaper than brass.

These factors have to be taken into account when deciding on which to use. So I don’t have a definitive response for your situation.

Really any time you need to reinforce a panel, it is because it is too large to reliably support itself. Often this is because it is too tall or too wide. Big windows have always been built in sections, with each stacked upon top of the lower ones. There are saddle bars or ferramenta added to the window opening to strengthen the window.

It is important to note that in compression glass is much stronger than steel. It is when the glass is in tension that it is weaker. So what the reinforcement is doing is resisting any lateral movement. It is not holding the glass up. The glass can do that very well on its own. The glass is subject to lateral movement from wind pressures mostly. But in some situations as in doors, it is subject to inertial movements - the door closes and sometimes slams. In other installations there is vibration – such as sidelights. The re-enforcement is to counteract or reduce this movement.

In general, if the panel needs reinforcement, it is too large as a single panel, and needs to be built in several panels. Some people hate to have the line of the panel joints, but the eye generally ignores those straight lines (unless they are out of true horizontal or vertical).

Some questions you need to ask yourself about reinforcement are:
Do you really need to reinforce?
Must it be within the panel?
Can you use external support?
Why would two hinges be better than one?

Remember the reason for not having a hinge is because the glass is the strongest element in a leaded or copper foiled window. Therefore a window with complicated lines will be a stronger window as the glass interlocks. If you look at many older windows you will see a number of hinges, and the windows are still there. I attach an image of a stair window that has been in place for just under 100 years. It has a multiplicity of hinges. I am not saying don't concern yourself about hinges, but keep a sense of proportion.


Nowadays, I keep all my reinforcements to the surface of the panels, not inside. Also if you want to join panels in a large window, it is not essential that the join be horizontal or vertical. It could be in a wave, sinuous curve or in a stepped fashion. Your imagination is probably the limit here, not the material.


The enquirer then sent pictures with further information.

“These are the latest 3 panels I’ve made for my bungalow out the back. They measure 1100mm high by 500 wide approx. I’ve made them all with different reinforcement applications. I was told they would not need any but still wanted to strength them up.

“The middle you can see I broke the hinge line with two pieces of re-force and on the other two I’ve gone all the way through to the outer border. All other lead lines do not go more than 2 pieces of glass before they are crossed by another piece of lead to break up that hinge thing.

“Due to the size/design I’d appreciate your thoughts on what I’ve done being correct/overkill?”




The two outer panels are supported appropriately. I believe the right one is adequately reinforced, and the left is over reinforced, but there will be no harm. The middle one is not adequately reinforced. The broken horizontal reinforcement transfers the stresses to the middle. The vertical one also transfers the stresses to the middle, only a little higher.

For reinforcement to work, it needs to transfer the stresses to the sides/tops of the panel where they will be captured by the framing. Thus the reinforcement needs to be a continuous line. The strongest reinforcement will be across the shortest dimension of the opening.

The weaving of the lead lines described by you as “lead lines do not go more than 2 pieces of glass before they are crossed by another piece of lead to break up that hinge thing” is exactly the right thing to do in these panels.

In the case you are illustrating, there should be no problems for several generations at minimum and possibly for a century.


"I’ve also included one other piece I’ve designed and cut which is going to be installed in an internal wall inside a home. Its 800/800mm approx and due to it being kept out of the weather was wondering about what type of re-enforcement structure would suit?"

As this will be an internal panel, I suggest that the best reinforcement would be a toughened/tempered sheet of 4mm float glass installed behind the panel. This will provide support in case someone leans against it. Yes, there is a diagonal hinge at the trunk, but the strongest reinforcing for this would simply be a horizontal bar behind the panel, which would look ugly and I don't think you want anyway.

Positioning the Circle Cutter.

If you have a suction cup on the circle cutter, it will be easier to hold in place. But a three legged circle cutter is possible to keep in place too.

In both cases, one hand holds down the centre and the other operates the cutter. Make a test circle with no pressure to ensure before you start that the cutting bar will not bump into anything else on the bench. This also ensures that you have the circle to be cut placed appropriately on the glass.

To make the score start with the bar under your supporting arm and swing around to the other side of your arm until you hear the click or scratch indicating that you have come back to the start.

Lead and Copper Foil in the Same Panel

It is possible to combine copper foil in a leaded glass panel.

The copper foiled piece should be soldered before inserting it into the lead came. In this way the soldered together pieces become very like another piece of glass.

There are some special considerations, of course.

The copper foiled piece should be designed as though it were a single piece of glass and so can be accommodated into the surrounding pieces of glass. Copper foiled piece should not have severe undercuts which would make it difficult to insert into the surrounding glass. It may be necessary to incorporate a piece of the surrounding colour to make it fit into the panel.

The copper foiled piece should be finished with all the beads on both sides. If one side is left flat, it will collect water if on the outside, and catch on any cleaning processes whichever side it is on. However, the piece should be tinned only on the outer edges. This will ensure that the copper foiled piece will slip into the came.

The image below illustrates a copper foiled piece incorporated into a leaded panel.

This section of the panel shows the accommodation of the main leaded panel with the copper foiled piece with a line from a petal to a leaf. Otherwise, it was fitted as one piece.

Templates of openings, 6

When the opening is in stone, slight variations occur in the process of taking a template. The main difference is that the rebates are concealed. The rebates are slots into the stone. Thus, the template must slip into the slotted rebate. In these cases, the stiffer the material being used to take template, the better. Usually, thin plywood is the best material, as it has to be manipulated many times and in ways similar to the final panel.

Things are further complicated, as tracery is more common in stone than in timber framed openings. A complex opening shape may require two or more parts to enable the panel to be inserted. The taking of a template will help greatly in figuring out how the panel will be inserted into the opening.

Additionally, when the template is in position, you should mark the visible portion of the opening onto the template. Mark which is the inside and which the outside. Finally, mark on each template which side has the deeper slot as this will help in installation.

Templates of Openings, 5 – Irregular Openings

Irregular openings such as trefoils and other tracery need to have templates taken with consideration on how the final panel can be put into the opening.

In the cases where the whole of the rebate is exposed, it is normally possible to put the panel in as a single whole piece.

So, the template is taken as for any other opening. It is more complex and time consuming as there are so many more sides than in a simple rectangular or circular opening.

Templates of openings, 4

Round headed openings can be considered as a special case of a circle.

The horizontal you must find is the shoulder of the window. This is the place from which the curve springs on each side. The opening is generally vertical up to this point and then begins the curve.

You need to make sure you have marked where this shoulder is on the template. You should indicate any reference points from the frame onto the template.

The join to the lower part of the window must be made obvious. Normally there will be an overlap between the lower rectangular template and this approximate half circle. You need to mark where this overlap occurs, if you do not fasten the two sheets together. This can be done by marking across the two sheets in a few places. This will enable you to join them exactly back at the studio.

Templates of openings, 3 - Circles

Occasionally the window is circular and sometimes an oval. In both cases a template is important. The circle rarely is exact. Take the template in the normal way and then ensure you mark the verticals and horizontals for the opening. You often can use the jointing in the woodwork to help with these. Also mark any other reference points from the opening. Finally, mark which is the outside and which the inside.

This procedure will ensure that you will be able to fit the panel into the opening.

Templates of Openings, 2

Irregular rectangles

If you have found or can see that the opening is not a true rectangle and cannot determine where any right angles are, you need to take a template.

The objective is to make a piece that will fit into the opening without bending or being too small for the space. It will be the same size as the finished panel and so you will be able to put the finished panel into the opening without needing to trim or expand the panel.

First, trim the sheet of material you have chosen to use to a size a little larger than the measured size. Place the uncut side along one of the long sides of the opening. If the opening is a portrait format, place it on the right or left side as convenient to you.

Next, adjust the bottom by marking a line on the sheet. This is where a second person is very useful. One person can hold the sheet in place on outside of the opening and the other do the marking from the inside –in the case of the rebate being on the outside and vice versa if the rebate is on the inside. The marked line should be as close to the edge of the rebate as possible. The special case of an opening in stone will be dealt with separately.

Then take the sheet to a place where it can be safely cut. A long metal straight edge and craft or “Stanley” knife are often the best aids to cutting straight lines. Replace the sheet into the opening after cutting, and make any adjustments to the size and angles of the sheet at the bottom by marking and cutting as necessary.

When the side and bottom are adjusted, start on the other side. Proceed as for the bottom.

When the side is finished, start on the top.

Finally, present the whole sheet to the opening to make sure it slips into place with no snags, or bending of the sheet.


It may be that the opening is too large for a single sheet. In that case you will need to work with two or more sheets and try them together for the final fitting into the opening. You can put them together in the window. You can fasten them together with tape or other fasteners to make one sheet. You can also make two parallel lines both at angles and at intervals across the sheet so that when you get back to the studio you can exactly reproduce the full sheet by matching the marks and then firmly fastening them together. This makes transport of large templates much easier.

You will know that a panel made to a template made in this way will fit into the opening, no matter how irregular the opening may be.

Templates of Openings, 1

If you have an irregular opening, it may be best to take a tracing of the opening. Usually this will be in a larger opening and so a helper may be necessary to hold things.

The material used to take the template must have a few characteristics:
- It must be stiff enough to have the minimum possible bend over the width or height of the opening
- It must be easy to mark with a pencil or other implement
- It must be easy to cut or shape
- It should be light to make it easy to lift it to the opening for the many adjustments that will be required.


A number of materials can be used: stiff card, mounting board, corrugated cardboard, thin plywood, and many other sheet materials. I have found stiff corrugated cardboard easy to use.


More information in this series is at:
Irregular rectangles
Circles
Round headed windows
Irregular shapes
Stone

Measuring a Rectangular Opening.

1 - Measure at both the top and bottom for width.

2 - Measure at the left and right sides for height.

If it is a tall or wide opening measure at intervals and at least in the middle of each side.
So far so good. But how do you know that it is a rectangle rather than a parallelogram? Measure the diagonals – bottom left to top right and top left to bottom right. If these measurements are equal or +/- 5mm you can consider the opening to be a rectangle.

With bigger variations you may set out the cartoon using the measurements for the opening. Still, you need to know where the right angles are, if there are any, to be able to set out the cartoon to properly fit the opening.

So you may wish to take a template of the opening.

Bulging lead panels

There is probably no means by which leaded glass, because of the innate character of lead as its skeleton, can resist its propensity to bend, bulge and sag. Evidence of these occurrences does not necessarily foretell disaster or immediate collapse. Bulging does not necessarily indicate the need for action or re-leading.

There are three basic stages through which stained glass passes on the way to requiring repair;
1. Bulging, bending and sagging
2. Loss of putty and breaking of solder joints
3. Unhousing of the glass from the lead


The points at which solder joints break depends on the materials used.

Since lead, compared with solder, is a resilient material abutting the more resistant solder, breaks will occur most frequently at the junction of the solder with the lead.

With zinc, the situation is reversed. The zinc is of greater resistance than the solder. As a result the break most often occurs on the solder at the point of the zinc junctions.

It is the very existence of resilience in lead which responds to the expansion and contraction of glass that permits the more healthy survival of the glass over the less sympathetic accommodations of either zinc or copper foil. Leaded glass, unlike any other medium, has the unique capability of having its skeleton (lead) replaced, when the need arises, without damaging its body (glass).

Combing Glass

This process is done at relatively high temperatures for fusers – around 925C. It consists of pulling or dragging the surface of the hot glass to produce a marbling effect.

Preparation:
A batt washed ceramic shelf is the best surface. You can use fibre paper on your shelf, but you must be careful to avoid raking deeply enough so that you pick up the fibre and drag it into the glass.

Make a boundary with 10-12mm fibre board on your shelf. You can use strips - for the most efficient use of the board – or cut a shape from a sheet. If you are using strips, fasten them together with wire staples. This will resist the glass flowing at the edges.

Place the glass into the space created by the fibre board. You can place 10mm strips on edge to form very tight lines, you can shingle glass to give broader lines, or you can place the glass in a more random way to give quite different effects.

When shingling or placing glass randomly, it is often best to cut a sheet of iridised clear to lie on the bottom to ensure you have enough depth of glass. Placing the iridised side of glass down toward the shelf provides an additional release, and can give added interest to the back. Anything less than 8-10mm thick leaves the glass pulled away from the edges in the direction of the combing.

Firing:

The initial temperature rise can be fast because the glass is made up of narrow strips. No bubble squeeze is required for the vertical or shingled strips, as there are easy ways for the air to escape. Randomly placed glass should have a bubble squeeze at around 650°-675°C for 30 minutes at least. Otherwise you can fire at about 300°C/hr to 925°C.

You need to programme a soak at that temperature for approximately 120 minutes. This soak allows you to do the combing and have the kiln recover temperature without needing to re-programme. When the combing is finished you cancel the soak after the kiln recovers to 925°C (which allows any peaks generated during the combing to settle down).

Allow or programme the kiln to cool as fast as it can to the annealing temperature and soak for 120 to 180 minutes. Set the annealing cool at 30°C/hour down to 450°C, then 60°C/hour to 370°C and finally at 200°C/hr to 21°C.

Combing:

Safety first. You must do you combing in a kiln that has a safety switch to turn the power off once the lid is opened a short way. If your kiln does not have such a safety device you should reconsider your desire to comb in your kiln. Many say you can overcome this by switching your kiln on and off at the wall socket. However, in doing so you also turn off the controller, making it necessary to re-programme your kiln each of the several times you have to reach into the kiln with your raking tool. This is essentially impractical.

The combing tool is a pointed steel rod, bent at right angles to the shaft - often called a rake. The shaft should be of wood to avoid holding a hot metal rod in your hand. Stainless steel rods are best as mild steel can spall and leave flakes of metal in or on the glass. The rod and wooden handle should be soaked in water while the kiln is heating up. The wet wood will not char so quickly as the dry. This bucket of water should remain beside the kiln so you can cool the metal point, when it begins to stick.

The second bit of safety. You will need to wear gear to protect yourself against the heat. A full face visor is important as the heat will singe you hair. You need to have heat resistant gloves. You need to have heat resistant sleeves to go over your arms. You should wear only natural fibres - cotton and wool are best, as they smoke before bursting into flame, giving you some warning that things are just too hot. An assistant to hold the kiln door/lid open while combing is advisable. And the assistant should have the same heat resistant gear that you have.

You begin to do the combing at 900°C. The glass will be soft enough to be pulled by a gentle stroke across the surface of the glass. Avoid digging into the glass. That will pull or push a gather of glass ahead of point. This leaves a characteristic droplet shaped mark in the glass at the end of the stroke. It may also go deeply enough that the kiln wash or fibre paper that is underneath the glass will be pulled up into the glass. Only light pressure is required to do the combing.

You will only be able to do a few strokes with the rake before the temperature of the glass falls and the glass resists movement. When the glass becomes difficult to move, it is time to close the lid and let the temperature recover. You will have to do this numerous times, until you have the look you want.

Another limitation is the speed that the rake metal heats up. When the metal becomes hot, it sticks to the glass. Whenever the rake is not in use, it should be in the bucket of water cooling off, and re-wetting the wooden handle.

You can comb the glass in any manner you wish. To get the traditional feathered look, you need to alternately pull and push the rake to give chevrons in opposite directions. Experienced people sometimes use two rakes – one to pull and one to push - at the same time. You can also rake diagonally across the sheet and even across the previous rakings. Some experimentation will show which effects you like best.

Annealing Open Face Castings

You need to double the annealing time for an open-faced casting over the schedules for the same thickness, because the glass is cooling from one side only.  The usual schedules are premised on cooling from both sides equally. The schedules given for 50mm thick open face castings should be used for a 25mm thick open face casting.

If you could cover your open-faced casting with something of equivalent insulation as the investment around the glass you could go back to a 1" schedule.

So an open-faced casting 25mm thick needs to be annealed using the schedule for 50mm thick castings as follows (for Bullseye glass - make adjustments for different glasses):
482°C for 8 hrs
4°C/hr to 427°C
7°C/hr to 370°C
23°C/hr to 21°C

See the Bullseye chart for annealing thick pieces.

Based on Don Burt’s work

Cutting Oil

Why use a cutting fluid?

No matter how good a fissure is when scored dry, it is better if scored with a liquid between the wheel and the glass. Several good things happen with an "oil" cut and only one undesirable thing.

The bad thing is you have to wash the glass afterwards, but in many cases washing is required anyway.

A good thing is the fluid reduces the effect of healing - the compressive strength overcoming the fracture caused by scoring. It is probable that the liquid seeps into the fissure contaminating it enough to prevent atomic reattachment of the molecules.

Cutting oil reduces chipping and prevents a flaky score line. The oil tends to provide a hydraulic cushion between the glass and the wheel. This allows more uniform transmission of the shearing forces into the glass at an angle dictated by the wheel, not by particles of crushed glass.

It is important to check the cutter wheel is moving freely, since a wheel not rolling freely may skid. Skidding causes abnormal wear to the wheel and subsequently it becomes a skipper.

You should not use kerosene by itself because it removes whatever oil is on the axle.


Prepared from information provided by Fletcher-Terry company

Tilted Cutter Effects

A tilted glass cutter has the effect of changing the angle of the cutter wheel.

It narrows the angle on one side and increases it on the other side. So on the side tilted away from vertical (which is what happens when you look down the side of the cutter) has an sharper angle with the glass. This is likely to produce chips along the cutting line.

The side which is tilted toward the glass has a more blunt or shallow angle with the glass. This produces high stress along the line.

The combination of these two effects make for a rough edge when broken and for break failures because of the stresses being at angles to the desired vertical fissure line.



Prepared with information from the Fletcher-Terry company