How to Apply Copper Foil to Your Stained Glass Shape

    Published: 06-16-2009
    Views: 46,049
    Stained Glass Artist Phillip McKee gives his top tips for applying copper foil to a stained glass shape.

    Phillip McKee







    Hi, I am Phillip McKee of McKee Stained Glass and I am going to show you how to properly foil a cut piece of glass for use in a copper foil method stained glass creation. Once you have your pattern piece properly sized and ground, now it is time to apply copper foil. Copper foil comes as a roll in which the copper is exposed on one side and an adhesive backing has been applied to paper. Copper foil can also have a colored backing. In this case, we are using black backed foil, because we will be applying black patina for a traditional black lead line look. You can also leave your solder lines silver or apply a copper patina. Copper foil in addition, comes in many different widths. I recommend using 7/32 inch copper foil. This is a relatively wide foil that fits on the vast majority of glass. So that that way, if you have trouble centering as a beginner, you can easily trim away excess and still have a well foiled piece.

    If you use too smaller foil, you will run into difficulties of not having enough foil showing on the faces of your glass. If you want to do decorative soldering later on, you might wish to considering using a larger foil at this time. I have placed my foil inside of a copper foil dispenser. This is a good idea because it keeps your roller foil from unraveling and becoming an untidy mess. It also means that you can use the extra slot to guide your paper backing away from you, making your job much easier. I have placed an extra Morton Layout Block on my Homasote board to act as a stop, so that as I pull on the foil, I do not pull the dispenser. When we are foiling our glass, always start on an inside edge, by that I mean do not have your foil overlap on the sides. Have it overlapped where it will be bound on two sides by glass.

    Occasionally, when soldering or later in the life of your piece, the adhesive on the foil can become unstuck; this can be caused by excess heat from your iron, denaturing the adhesive or because of contaminants like glass dust or finger oil getting in the way of a proper adhesion. By putting your overlap in the center, you make certain, that your piece will not unravel. So, we are going to start right here, the hardest thing for people to understand when they are foiling is that you are not applying foil to the glass to visualize it, think of yourself as applying your glass to the foil, you want to center your glass, in the center of the foil and then slowly roll the glass down that center path.

    Many people find it easier to do this with one eye closed, I am one of them. By keeping one eye closed, we ensure that we are not having any error in our centering technique. Then, we come back to the side on which we begin, we continue foiling. Once we have an overlap, we stop and cut it short. Now it is time to pinch the glass. Crimping or pinching the foil down onto the glass is absolutely important because we need the foil to lie flat on the sides towards the faces of the glass. Pinch it, just like you would anything else, come from the outside and pinch in, outside and pinch in, outside and pinch in. Get to the corner, use for finger nails to tuck in the corners, that means that when you fold it over on the new side, only foil will be showing. If you are not careful, you can expose adhesive and adhesive does not stick to solder.

    Continue crimpling along the edges and on straight sides, do not give in to the temptation to run along the edge. Copper foil is paper thin, if you attempt to run along an entire edge to crimp it down, you are almost guaranteeing yourself, the mother of all paper cuts. It will hurt and it will bleed. Now, on this compound curve, we come to a point where it is an inside curve. If you simply pinch on an inside curve, you run the risk of breaking the foil, since it is having to actually expand slightly as it goes down. Since we do not want to break the foil, we use our own body heat to our advantage. Rub your finger back and forth along the foil, begin to slowly lean inwards. By the time you are done, your foil is down neatly and there are no breaks, do the same to the other side. Do not worry, if a break occurs, it can be repaired. Once you have foiled the piece, now it is time to burnish.

    Burnishing is the process by which we make sure that we have full adhesion, we are pushing against the foil so that it sticks to the glass and removes any air bubbles. In this case, I am using what is known as a fid or a lathekin. First, I burnish along the sides, being careful at the corners not to chip them off and then I place my glass flat against my Homasote board. To burnish these face edges, you need to have it lying flat. Now, push down with the fid and begin pushing the foil against the glass, continue doing this until you have gotten rid of all unnecessary air bubbles. The foil will actually change its appearance, notice the slight ridges and after burnishing. We do the same to both sides.

    Be careful when you are burnishing around to the overlap point, you do not want to accidentally peel it off. After burnishing, we take our exacto knives and we trim away any unnecessary foil. Your most likely spot is going to be where the overlap occurs because you may not have placed that last bit of foil in perfect alignment. If you cannot see it, use a magnifying glass. Begin where the foil is at its proper width, come to where it is too big and just slice it off. Do that on both sides if needed, check your edges for breaks or extremely wide sections and now you have a foiled piece of glass. Do that with all of the pattern pieces you have cut and we are ready to move on to the next step which is squaring up our pattern using our layout blocks in preparation for soldering.