The method described here is sometimes called the “Tiffany” method, after Louis Comfort Tiffany, famous glass designer and manufacturer. The basis of this technique is applying solder to copper foil-edged glass pieces. Panels can also be made using lead cames. Both techniques require practice and specialized equipment. I have made stained glass panels and objects using this method since 1992. My first panel was awful – but I kept it, and each new piece teaches me something new.
Making a Pattern
Start with a drawing or a photograph of the subject of your project. Color choices should be thought about right from the start – for example: the main subject of the panel needs to be a different color than the background. The pattern is the interpretation of the drawing or picture that makes it able to be expressed in glass. This is also the point where the structure of the panel is taken care of. If this is your first design, keep the shapes simple ! Draw as few lines as you need to show the picture. Let color differences in the glass define as much of the texture of areas as you can.It is important to consider your cutting expertise, the limitations of the equipment you will be working with, and the kind of glass you expect to use. The size of the final panel should be considered – the detail in the finished panel must still be large enough to be cut or overlaid.Simple cathedral glass cuts more uniformly and reliably than more exotic textured and mixed colored glass. Expect to have to cut pieces again (i.e. produce scrap glass !! ) more often from the latter.A very tight inside curve on the pattern has to be cut with a band saw or ground out with a small diameter router bit. Don’t design for a tight inside curve if you can’t cut it! It is best to design at the scale of the final panel. It is easier to see the curves you are drawing and to visualize the size of the soldering between. Draw the lines on your pattern with a heavy pencil line and finalize with a wide marker. The wide lines will give a better idea of the finished solder lines. You may wish to remove or adjust lines to balance the pattern. You need to locate the subject of the panel onto a background that will provide the means to cut the shapes you need for the design in a way that won’t distort what you have chosen as your feature but will prevent weakness in the whole piece. This is also a good time to consider where you might like to position hangers or attachment areas. It is best to be able to add attaching devices behind solder – i.e. where they won’t show when light is behind the panel. The final panel needs to stay together without warping and especially without cracking. The pattern lines provide the strength in the panel and can be used for reinforcing on larger pieces. Glass is a heavy, plastic medium that likes to “sag”! Vertical lines will strengthen the panel. T-junctions and X-junctions of pattern lines will stop the panel disintegrating into smaller sections. Number each piece on the final pattern. Remember to underline the bottom of the number – 6 and 9, and 2 and 5 can also be confusing. It is helpful to show with an arrow where lines should flow. For example, the direction of coat of a dog or the direction of water flow. This might not be important in every project, but it is a helpful habit to get into. Make at least 3 copies of the final pattern –
* Copy 1: Colour this pattern using approximately the colour of the glass you will be using. At this point, some adjustments may become obvious. This copy can be attached above your work area for reference as you work.
* Copy 2: This copy will be cut up to give the pattern pieces to stick onto the glass. Clear vinyl shelf liner can be used for this copy – the vinyl makes the pattern piece more durable during grinding and fitting. If the glass piece has to be re-cut, you can remove the pattern piece and reuse it. Apply the vinyl carefully to the intact pattern before cutting to prevent bubbles or creases which may distort the pattern. Cut through the middle of the pattern lines.
* Copy 3: This copy is used for layout – You will pin the pieces down while you work on them – flat plywood behind works well.
Keep the original pattern – you may want to make the panel again.
Choosing the Glass to Use
This part of the procedure overlaps with making the pattern – the pattern may be shaped by the variations in the glass you choose (or have available). When you look for the right glass for each piece on your design – look at the color in reflected light and hold it up to light that will be behind the finished panel – a window panel must have glass that looks the way you expect with daylight passing through – not just the lamp over your workbench. An interior panel will be seen with daylight hitting it, and passing through – and with lights in the room from both sides. The variations in color and transparency in different lighting conditions are incredible. A panel hung against the wall will be affected by the wall colour (or wallpaper pattern!). Unless you are incorporating this into the design, use opaque glass. Unless the main feature of your panel is VERY brightly coloured, let the background glass be just that – in the background. There should be a contrast or bold difference between glass used for the feature of your panel and the glass “filling in”. Heavy colour variations in background glass will interfere with the outline of the main feature and can make the whole panel very “dark”. An almost colorless background will bring the other glass used “forward’. The large variety of textured glass that is available can be used to good effect to define the background areas (make sure to align and match up any obvious patterns in the texture).
Cutting and Fitting the Pieces
Select the sheets of glass for each colour and clean them (window cleaner). Stick the pattern pieces onto the glass you intend to cut. If you have more than one pattern piece on a sheet, make sure you can make the cut for each piece. For areas on the glass sheet that you have chosen for a specific colour or texture, it is better to cut the piece too large and grind off the excess than to break the glass. (See the notes above regarding inside curves) Stick the pattern pieces to the glass – rubber cement or “school” glue works well. Attach a third copy of the pattern to a “layout” board (plywood works) The board needs to be a smooth, level surface able to withstand the heat of soldering, and to accept push pins or small brads. Cut the glass. Use a glass cutter or water cooled bandsaw. ALWAYS wear eye protection. A water cooled router is used for grinding, make sure the router bit is constantly wet and doesn’t become fouled with debris (glass sludge and chips).
Always, always protect your eyes.
If you grind with a coarse grit or with a worn out bit the edges of the piece will be chipped – which will be very obvious if any chipping shows on beyond the foil on the finished piece. Leave the pattern piece on the glass, clean any sludge from the piece and place it on the 3rd copy of the pattern as you finish grinding it. When all pieces are cut, check for missing pieces (especially on intricate patterns). As you are fitting the cut ground pieces onto the pattern board, remove the pattern pieces (don’t throw them away until the panel is completely finished and cleaned) – mark spots that are too big to allow a smooth fit, with a marker or wax crayon. (You should be able to see an even amount of the pattern line on the board above each piece you lay down) Regrind these high spots very conservatively until the pieces fit like a jigsaw. Keep cleaning the pieces you work on. There should be no tension between any pieces and no glass chips behind any piece. Work methodically across the board until the panel is covered. As each piece is fitted, use push pins to keep it in place – the push pin holes should be directly on the pattern lines. Check the fit and the look of the whole panel before you move on to foiling. Look especially for any texture or color mis-matching.
Foiling
Leave the push pins in position around the panel and take out each glass piece individually for foiling. Make sure there is no oil on your work area, or your hands. Thin copper foil (which comes on rolls and in sheets) is applied to the clean edges of every piece of glass. The roll foil is adhesive backed. It is important to cover the glass evenly – with the same amount of foil on each side.
* Don’t start to foil at a corner – where several glass pieces meet is usually where fitting problems can occur (especially with long narrow pieces). An overlap of about 1/3″ is sufficient.
* Special attention is needed where the foil comes back to itself – make sure the edges line up – any mismatch will be very obvious. The foil is what the solder fuses to and what makes the joint strong. The width of foil on the front and back is what determines the thickness of the final soldered seam.
* Narrow foil makes for a smaller seam. Wider foil can be used to highlight a seam – for example, to define the stems of flowers or reeds.
* When you have chosen glass of different thickness, you need to use pieces of card to make the front surface level before soldering.
* Depending on the finish you use on the solder (patina) you will need to use silver or black backed foil to edge transparent glass, the standard foil is grey on the back (adhesive side) and will look very bad viewed through transparent glass with a black or silver finish.
Although soldering can be forgiving, the pieces of foiled glass need to fit together as closely as possible, but not under tension which will stress and crack the surrounding glass pieces. A close even joint will be strong and attractive. It is hard to raise a smooth bead of solder on a crumpled foil edge.
It is important to have the foil smooth onto the glass and flattened carefully at corners and the seam. This is sometimes called burnishing. It can be achieved with the fingernails but a small plastic tool called a Kwik Crimp is best. Before you use it – make sure your corners are folded neatly and lying flat to each side of the glass or they will be ripped when you burnish over them. Again, work methodically across the panel – you may need to adjust pieces as the foil increases the size of each piece.
Soldering the Pieces together
Flux will corrode metal and “eat” skin. The fumes from the flux are also very bad for you. Your work area needs to be well ventilated and you must work carefully to avoid skin contact. Flux works by removing any oxidation from the copper foil surface, leaving a clean area for the solder to fuse to. All copper must be fluxed before soldering to allow you to make a smooth soldered joint. Apply the flux just before you intend to apply the solder or dust and dirt will settle onto it and spoil the joint.
Look at the seams across the panel – if any junctions have a large gap it is best to attempt to plug it with some “crunched-up” copper foil. Although solder is quite forgiving – it will only bridge just so far. It is very frustrating moving pools of solder from front to back trying to fill a gap – and almost impossible to make a neat finished joint. Don’t use solder from the hardware store unless it is solid core 60/40 (lead/tin) The correct mix allows you to heat the solder but control the flow of it onto the areas you want. If the iron is to hot (or you have used too much flux, the solder will run through the joint and pool on the underside, or the flux and solder will spit at you !! If the iron is not hot enough the solder will not “flow” but will clump into unattractive globs along the seam. If you are right-handed, start at the top left of your panel and cover all the joints with a smooth layer of solder. You will be reworking the joints once you have soldered the reverse side, start by covering all of the foil with a smooth coating (tinning). Now it is time to solder the back of your panel. Turning a large panel can be a risky operation. it is best to cover a large panel with a cloth and then a sheet of plywood. The panel has little strength until both sides are finished. Take your time when you are “flipping” the piece. Repeat the tinning process for the reverse, then go back and add more solder; drawing it into a smooth rounded bead along the length of each seam. (this takes practice and a clean soldering bit) Flip the panel back to the front side and draw a bead along the seams as you did on the back. A good craftsman will finish both sides to the same quality.
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© 2009 Jackie Barnaby
All Rights Reserved
A short article on the finishing process is continued Here