How to Design for Stained Glass

As I find myself working on Christmas presents, that inevitably include some stained glass pieces, I thought it would be helpful for me (and hopefully some of you) to go over some important aspects of Design for Stained Glass.

The Wikipedia page for Stained Glass says: “Stained glass, as an art and a craft, requires the artistic skill to conceive an appropriate and workable design, and the engineering skills to assemble the piece.” In this instructable, I hope to explain just enough of both aspects to illuminate (no puns or Dad jokes today!) to provide enough knowledge in both areas for anyone to make informed choices when creating stained glass.

Now I am by no means an expert. I am largely self-taught after a beginner’s class 10 years ago. Having learned from the bottom up, I’ve picked up some nuances here and there that might be of some use. If you are a complete beginner, you will learn the terms and vocabulary necessary that will be a springboard to better design and better projects from the start. In the beginning, as they say – “you don’t know what you don’t know,” or better said: If you don’t know what you’re looking for, you’ll never find it. If you are not a beginner, you may pick up a tip or two. There is a lot to remember and I had to dig through my years of notes to compile this list.

If you are completely hesitant about Art and Design in general, have no fear- we are going to dispel some myths. Creating a design comes down to one of two things- realism or abstraction. At the end of the day it is just one or the other to varying degrees. Let’s say you want to make a panel of a horse. On the one hand, you can try to make it as photorealistic as possible and include every last detail. On the other hand, you could give the impression of a horse with the fewest lines possible. One is not better than the other, and both can be done really well. Just like learning to draw, you must re-learn how to see and notice every detail. Our brains have evolved to use as little energy as possible: “That is a horse, that is a house- done.” We shut down and don’t notice the details and the obvious hidden in plain sight, this is why people draw some variation of basic shapes to represent a house and not a rendition of the actual house. Once you understand what you are looking for/looking at, the rest is just practice. You won’t make a perfect panel the first time, just like you won’t draw a perfect horse the first time. The great thing is this- you can (and should) make multiple drawings (virtually free) until you are happy with the design. Like Frank Lloyd Wright said: you can use an eraser at the drafting table or a wrecking ball on site- your choice.

Your imagination.

Paper.

Sharpie.

Crayons or Colored Pencils.

We all must start somewhere, my advice to you is to begin where you are. Even though stained glass is somewhat obscure compared to other hobbies, it is no less attainable. The first photo shows my first attempt at stained glass. A friend of mine worked making repairs in a restaurant and knew that I was interested in learning stained glass. One of the light fixtures happened to be stained glass and was broken beyond repair. He gave me the lamp so I could take it apart and see how it was made. After taking that lamp apart and doing some initial research, I bought a $15 soldering iron from the hardware store and cobbled this together from the broken pieces. It’s awful, but it was the first jump I needed to take. In time I had the opportunity to take a beginner’s class through a community center adult continuing education program…you know, the kind that also teach you how to make salsa and dance salsa at the senior center. I eventually remade the turtle- turtle 2.0, but guess what? The people I gave it to still have Turtle 1.0 in their bathroom window and turtle 2.0 in their closet...

Just jump in there and try some things. No amount of YouTube videos or research can take the place of having actually done something, and once you have done it once…you’ll be hooked.

To get started, we have to talk about glass…it’s what this is all about! Glass is a finicky material to work with, it’s basically a solid that wants to act like a liquid. Think of glass like a block of ice, with a tough outer shell. When we say we are going to cut glass, that’s actually not what is happening. We are scoring (scratching) the glass, and hoping it breaks where we want it to. To get a good “cut” you need to score the glass with the right amount of pressure. Too little pressure and the glass won’t break, too much-and you will have created many fractures in the inner layer of the glass that can break where you don’t expect. There is no way to explain this other than to do it until you get a feel for it. A good score takes about 3 lbs. of pressure and produces a scratching sound along the length of the cut. Because you have to put those 3 lbs. of pressure on the cutter, you typically don’t put the cutter right on the edge of the glass, because the pressure will break off a chunk or fracture the edge, so start your cut just inside the edge and stop just before the other edge.

The first rule in cutting glass is you have to start and end the cut at the edge of the glass. This means you can not start or stop part way in the glass. This is why Stained Glass has the look that it does. All those extra lines you see are for a reason, though I don't want you to get lazy and just add a bunch of extra lines and cuts if you don't need it in your design.

So then, the bad news: you cannot achieve certain shapes in stained glass- period.* With that said, anything is possible- right? We’ve got technology, right?! You could technically get a water jet and cut any shape you please. You could cut your name out in intricate cursive and solder it together. The problem is, once you do that- it will crack and break under its own weight. It might not even survive the heat to solder it together. You have to literally melt metal in between the glass to hold it together, and that rapid expansion and contraction due to heat can fracture thinner pieces of glass. I mentioned you have to start and stop cuts at an edge, this means there is one type of shape you simply cannot do- the inside 90-degree angle. You can’t start cutting, turn 90 degrees and continue cutting, the glass will want to break in a straight line. Even if you cut this with a water jet, you risk the piece cracking due to gravity, soldering, or regular handling. It’s just not a good idea to make something that is going to break shortly thereafter. Besides that impossible shape, there are 3 shapes you should avoid in your designs: the hourglass, the deep inner curve (approaching that 90-degree problem again) and a thin extending tail. In each of these examples, you create a point of weakness that can crack the glass or make things difficult in later stages. This is not to say you can’t ever create these shapes- I have done them all to a certain degree- it just means you will have to compensate in other areas of the design.

When it comes to actual cutting, there are only three kinds of cuts: straight cuts, outside curves, and inside curves. Straight cuts can be made with the aid of a ruler, though it is challenging to follow a regular ruler with a glass cutter. There are systems you could purchase to help with this, or you could use a thick ruler with some cork attached to the back. The cork will help the ruler not move around while you are making the cut (glass is slippery!). Outside curves are simple to make, and any irregularities can be smoothed out with a carborundum stone or stained glass grinder. Inner curves are the difficult ones, and generally you need to make several smaller cuts to get the curve you want, if you try to cut it all at once, the glass usually wants to break in a somewhat straight line, and my not follow the curve you need.

Another thing to be aware of when you are cutting heavily textured glass- cut on the smooth(er) side. The wheel on glass cutters is quite small and can get caught in textured glass. Textured glass usually has one side that is smooth or smoother. This is the side you should make your cuts on, just be sure you take this into account when placing your pattern, you generally want all the glass pieces of the same color to be facing the same direction. Or do you?...

Glass comes in an array of color and textures, it can be a bit overwhelming at first. To break it down and not get too complicated, let’s separate them into 3 types: Clear or transparent glass, translucent glass, and Opal glass. As you might guess, you can see through transparent glass. You can get some colors that are transparent, or only mildly distorted. The next category is translucent, they allow light to shine through the glass, but you generally can’t see through them. This is what most people think of when it comes to Stained Glass. All of these can be smooth or heavily textured. The last category is opal. Light does not shine through these types of glass. They can be any color or even mirror, but no light will shine through. These are used often for fusing or mosaics since they won’t be back-lit in a window. Glass is colored by adding certain metals and minerals to the clear glass, then rolled flat onto a sheet like a pizza dough. Because of this, you can special order the color you want with the texture you want as well. Look for sample packs at stained glass shops to understand the palate you can work with.

The important thing I want to point out with glass types is that those 3 categories blend into each other. You will see some glass called Opalescent, which means it is something in between opal and translucent. Just make sure you are getting what you want. You don't want to make a panel, only to hold it up to the light and realize one type of glass won't let light through, and throw off the composition of the window. If you intent to do that- great! Just know what you are after.

I made a piece years ago that had clear glass, solid black glass, and mirror. I think those 3 combinations could be made into an amazing optical illusion. I'm still working on that...on the back burner...

Now that we have chosen and cut the glass, it’s time to put it together. For that you have two options: Copper Foil and Lead Came.

The best way to describe copper foil is to liken it to aluminum foil, it feels and acts the same way, only it’s copper, so you can solder it. It also has an adhesive on the back side of it that allows you to adhere it to the edge of the glass. The beauty of copper foil is you can get really intricate with your design. Because the copper foil is so thin, it will wrap around intricate shapes and very small pieces of glass. If you have seen a very detailed hummingbird or flower, chances are good it was put together with copper foil.

Copper foil comes in a few different sizes and types, and it may seem confusing at first. At the end of the day, there are only two things to think about: the size of the lead line between the glass, and the color of the backing. Usually you will be working with three thicknesses (thicknie?...shout out Chris...): 3/16", 7/32” and ¼”. A thicker line will obviously be stronger than a thinner line, but sometimes you may want to change the line thickness in your design. I will warn you though, there is not enough contrast to make a noticeable difference between the 7/32 size and the sizes next to it- usually you will want to go from the thickest line to the thinnest to have a noticeable difference. Most of the time the stained glass is viewed from afar in a window and that level of detail is lost. If your panel is a small decorative piece or inset in a front door, there is a better chance the smaller details would be noticed. The second factor has to do with the color of the lead lines. Left to itself, solder has a silver appearance. You can put a chemical patina on the solder and turn it a copper color or a jet black color. If you are using clear glass, and use regular copper foil with Patina- you will notice a difference: the front side of the lead lines will be one color, and the inside of the lead lines will be a different color. If your glass is translucent or opaque, you can ignore this aspect and use any type of copper foil.

One thing to beware of when purchasing copper foil: there is high quality copper foil that is stiff and strong, and low-quality copper foil that is thinner and tears easily. Usually the cheaper version is sold at hobby and craft stores and are inferior to those at dedicated stained-glass shops, but you can get away using either on small pieces. If you are making a larger panel or 3D work I suggest the better foil, the lower quality foils’ adhesive may not be strong enough and will peel away from the edge with repeated handling. You can even get copper foil that has been pre-cut with a decorative design.

There are some downsides to copper foil though… It takes a pretty good amount of hand-eye coordination to attach it to the edge of the glass. You are essentially trying to center the glass on the copper foil while it’s standing on edge. Then you pinch it over the sides and burnish everything down against the glass nice and tight. Again, there are systems you could buy to make your life easier, but generally people go back to doing it by hand, because they don’t always produce consistent results. Imagine trying to tape something intricate, and the tape is sticking and crimping where you don’t want it- that’s the main downside. Another thing I have noticed with copper foil is it tends to be stiff, and when you go around a smooth edge, the smooth edge doesn’t translate with the foil and you may need to trim it to get the same effect. You generally need to have a X-acto knife handy to trim any overlaps or parts that don’t look quite right. Sometimes the copper foil will tear and rip along deep inner curves and you’ll think to yourself- that’s fine…the solder will cover that. I hate to break it to you, the solder will only stick to the copper foil, and any tear or gap in the foil will be seen in the final piece.

Another thing to keep in mind when you are designing with copper foil is to leave a gap between your pieces of glass. This creates a miniature “I” beam when you solder the joints from the front and back. If you don’t leave a gap, the pieces are only soldered on the face of the glass and not in between and create a weak joint. It’s counter-intuitive to leave a gap in between the glass, but that is what is needed to create a strong solder joint.

When thinking about strength, there is the issue of reinforcing. Old windows were reinforced with rebar and most folks don't like how that might look. Today you can get a product called strong line, and put that inside areas of the panel to make it rigid. If your panel is larger than 24" you should consider a zinc frame- that is stronger than copper foil or lead came. The thing that creates the most weakness in any stained glass panel is called a hinge joint. A hinge joint is where a line in your design flows uninterrupted from one side of the panel to the other. This creates a point of weakness and the panel will want to "fold" along that line with gravity. You can strengthen any line with strong line, or better yet, interrupt the line so it doesn't flow all the way across the panel. You can keep the line flowing across, but where other lines intersect- have those lines interrupt the longer ones.

Lead came is pre-made for you and is usually sold in 6 foot strips, though you can buy it on a roll in longer lengths. It is usually in an “H” shape that allows you to put the glass on either side. The lead came is fit around the glass and soldered together at the intersections. There are many different sizes and types, usually the main difference being the thickness of the lead line and whether it is flat or rounded on the face.

A key thing to know about Lead came is it needs to be stretched before use. Stretching the came makes is rigid and strong. Think of an unstretched came like floppy cooked spaghetti, and stretched came like rigid, uncooked spaghetti. One of my first pieces was a large lead came panel that I did not stretch, and it was very wobbly- I eventually had to remake the piece.

It’s surprising how much wrestling and banging happens when assembling a lead came piece. You start in one corner and work your way out to the other corner. Horseshoe nails are used because they are flat and won’t dent the lead came while the pieces are temporarily positioned.

When you are finished putting a lead came panel together and soldering, it typically needs to be grouted. The “H” or “U” channel used in lead came is slightly oversized so the glass will fit. If this window is the only one between you and the outdoors, it will let wind and water inside. You will need to take glazing putty and press it into the seams and let that cure. It’s a bit messy, but the magic product that makes it all worth it is whiting powder. Once you have glazed the entire surface, sprinkle some of that on and burnish with a stiff brush. This will clean off the excess putty and polish the window. Bonus- the glass won't rattle!

We have talked about choosing and cutting glass, and the ways they can be joined. Now is a great time to talk about pattern shears. Pattern shears are scissors used to cut out the design for stained glass. Because there is a gap that you must account for in the lead came, these scissors cut out that gap to ensure your window is the correct size after assembly. If you didn’t account for that gap, the lead lines would add up and the piece would be too large for your opening. The problem is this- they don’t always work… some artists prefer to make the window from the center out, and then cut the outer edges to the correct dimension. Some artists prefer to use a popsicle stick with two X-acto blades attached to each side, they feel that gives a cleaner cut on the pattern. The three-blade scissors sometimes bind and don’t cut very smoothly. At the end of the day I’ve come up with what I like to call the sharpie rule. Whether you are making a lead came panel or a copper foil panel, the space you need to account for is about the thickness of a standard sharpie marker. Instead of having 3 different types of scissors (which I have…and don’t use anymore) or some home-made device, just draw your design in sharpie and cut the glass to fit inside the sharpie lines- end of story.

Now hang on a second…that puts a lot of constraints on my design you say! I can’t get ultra-detailed on the eye/beak/head feathers of my bird! Exactly. It is possible to make a tiny, intricate design with the smallest lead lines in copper foil. You can even combine really detailed work with larger components, but you are jumping into the advanced section, the deep end of the pool if you will… If you go that route, you are going to have tiny pieces of glass, that are VERY difficult to cut properly, then you are going to have to wrap that glass in a piece of copper foil or lead, then you are going to have to MELT metal into the corners and crevices of said piece. When you are done with all of that, the fine pencil drawing you had at the beginning will not look the same. My “oversimplified-rule-that-works-all-too-well” here: draw with a sharpie. Increase your scale or change your design. Don’t try to make glass do what glass doesn’t want to do. Scale is one of the most important pieces of this puzzle in my opinion. I’m not asking you to make a chair out of giant logs here, I’m asking you to not try and make one out of mini-blind slats that can’t carry a person’s weight.

When creating a design, I suggest you sketch the idea several times, thinking about how it will be built. Don’t create a line with your pencil...ahem SHARPIE that you can’t achieve cutting glass, wrapping it in foil, and soldering metal around the edges. As they say, creativity loves constraints. How can you work within these constraints and still produce something that is unique? You can look at each stage and decide how you want to achieve your idea. Maybe there is a color or texture of glass that will fit the bill. Should you use copper foil, or lead- or nothing? You can leave a gap in some areas if it is supported by other parts of the design. When done correctly, this has an amazing effect, making parts of the design “float,” being suspended and anchored by other parts of the design. You can also use overlay, ornamentation, and decorative soldering to get an unexpected effect (something we’ll discuss later).

When it comes time to solder your project, you have a few choices. There is lead free solder, 50/50, 60/40, and 63/37, to name a few. The number refers to how much lead vs. tin is in the mixture. In general, the more lead present, the easier it is to solder, and the least amount of heat needed. The temperature required to do this is usually between 500 degrees and 700 degrees. This is why you need a good soldering iron, and not one from the hardware store meant to solder tiny circuits. You should also solder in a well-ventilated area and never solder in flip flops or sandals (drips of melted metal- ouch!) The technique to get a nice smooth bead is to have a clean soldering iron tip, achieved by cleaning it with a salamoniac block or brass brush, and lots of practice. In general you want to tack all your pieces in place so nothing moves, tin the area if using copper foil (thin coating), then build up to a nice rounded bead. Remember what we discussed earlier about tiny pieces? Beware! You cannot hold the soldering iron in one spot for too long or you will crack the glass. Get in, solder, and get out! If you need to fix a splotchy area, come back to it later.

Patina is a chemical reaction that changes the color of the solder. There are 3 colors to choose from: you can leave the solder as-is (no patina) and get a silver color, you can patina it jet black, or you can have a copper toned color. You CANNOT patina lead free solder! I just have to throw that out there. If you want to create amazing jewelry pieces that you made with lead free solder so your 2 year old can put it in their mouth safely- I hope you like silver-‘cause that’s all we got. Trying to patina lead free solder will result in frustration, the copper and black colors will be extra dull and splotchy. Polishing the solder joints can help some, but ultimately the patina is a chemical reaction with the lead. I’m not scientifically positive here, just some hard eared wisdom.

One last tip…Something you might not realize with large panels: once you solder the front half of the design, you have to somehow flip it over and solder the back…without breaking/shifting anything. Things get complicated really quick. It’s kind of like putting together a trampoline, you think you know how it’s supposed to go, and only kind of pay attention to step 3…then you get to step 12 and realize you have to go back and correct step 3 for step 12 to work. Not that I know anything about that…

I can't bring myself to throw away any scraps, and it started to be a problem...ahem. I decided to try a variation on mosaic work and embed the glass in resin. This has worked extremely well and I'm SUPER happy with the results, since I can use even the tiniest pieces of scrap. If you want to see how I made those, check out my past few instructables.

I’m not going to get into the nitty gritty details here, but suffice it to say that there are many ways to achieve a little extra in stained glass. In my opinion, the glass selection and thoughtful design lines are enough. BUT, if you want to get carried away- here are several options to consider:

• Overlays: Take a large sheet of copper foil and cut any pattern you choose with a X-acto knife, you can then adhere it to the glass and solder the copper. Just make sure that you attach the sheet at the ends to some solder lines, if it’s free-floating in the middle of the glass it can fall off over time- no adhesive is fool proof over time.
• Brass filigree: these are pre-made designs in brass (usually small) that can be attached to provide some decoration. You can even get wings for angels, bases for lamps, kaleidoscope parts, etc…
• Decorative soldering: This is done by adding a decorative layer of solder on top of the structural solder. Usually a solder is chosen that melts at a lower melting point than the structural solder, to avoid melting through the base layer. Artist usually add small dots or waves that repeat along the solder line. If it is on a tree branch it can look like bark or small nuts/fruit.
• Etching: You can use a Dremel, sandblasting, or a corrosive liquid meant for glass etching and carve a design into the glass. I have used this to write on glass or make an intricate design. You can then color the design with Sharpie markers and wipe off the excess, the ink will remain in the etched area. The only think to keep in mind is Sharpie marker will fade in UV light over time.
• Fusing/painting: If you have access to a kiln, you can fuse certain types of glass together and create something new. You can even sprinkle bits of glass dust that will melt into the base layer and fuse permanently. The same goes for paint meant for glass, it’s usually some type of enamel that will fuse to the glass once heated- it creates a much better effect than sharpie, and is permanent!
• Found objects: You can take gems, agates, marbles, or any other object and permanently solder it to your piece. You can solder these on by wrapping them in copper foil or drilling holes and inserting copper wire. Think about the strength of the piece and make sure the solder lines can support the weight if you have a large object.

Ah, working in 3D…it’s such a great idea with so many possibilities- that doesn’t work 90% of the time. Hate to be a downer on this, it’s just been my experience that creating anything in 3D has a much better chance of not working than working. It CAN be done, I’ve seen a few that look…good.

Here’s the thing: make anything in 2D and hang it in the window, and you have a 90% success rate. Stained glass is inherently beautiful and very forgiving. Take that same idea and turn it into a 3D lamp or sculptural object, and the failure rate becomes 90%. Stained glass just looks better with natural light shining through it, put artificial light behind it and you lose something. You may disagree here but do me a favor- go Google stained glass lamps and tell me how many of them you like. You may find some Tiffany examples that are really nice, but I bet overwhelmingly you will find some that don’t look too great and are better relegated to an antique store. I bet some 3D pieces you have seen that looked good had their photos taken outdoors, instead of inside with a lightbulb behind it.

If you still want to try your hand at 3D work, here are some pointers:

• Be Patient.
• Use scotch tape to hold things together temporarily.
• Get inspiration from folder paper. (low res polygons)
• When you solder, make sure the area you are soldering is level with the ground- you may have to prop it up with pieces of wood or foam to hold it in the right position.
• Tin everything ahead of time before final assembly. Plan your work in stages to be able to solder the inside seams. (you might not be able to)

Stained Glass is an amazing artform that has a few very rigid constraints, but a world of possibility once you understand them. According to Jennie French, who in my opinion has the best book on Stained Glass Design: It all boils down to three things- “structural strength, responsive color selection, and beautiful design lines. Overlook one, and you have a ruined project.”

Use whatever method you need- camera, grid, projector…just use your own design. If you purchased plans, you are free to use them. If you took someone’s idea from the internet- not a good idea. Especially if you plan to sell that piece. Make it better!

When thinking about your design, ask yourself these questions:

Is this design strong, or is gravity going to tear it apart over time?

Am I using the right type of glass?

Do I have too many lines? (Like in writing, if you can leave it out- leave it out.)

Find inspiration. Ask why not? You know the rules now, go and bend some and create something unexpected that hasn’t been done before. Slow down, use a critical eye. If glass has to be re-cut, re-cut it- don’t do sub-par work. Break the plane, go against the grain. Don't let perfect be the enemy of good. There is no perfect, so have fun.

The great thing about Stained Glass is the same thing that is great about life: “The whole of reality [insert Stained Glass] is greater than the sum of it’s parts.” -Anthony Alvarado