Fusing Glass – Preparing the Kiln

    Published: 06-16-2009
    Views: 23,775
    Glass art expert Erwin Timmers demonstrates how to fuse glass and prepare the kiln.

    Erwin Timmers: Hello! I am Erwin Timmers and we're here at the Washington Glass School and in this segment we're going to talk about preparation of the kiln shelves, what you need to do to get it ready and how to place the glass on the kiln and we'll talk a little bit about the kilns and stuff. I've already taken the shelf out of the kiln. This is how they usually come out. The white stuff you see on here, this is the kiln wash, basically a separator that keeps the glass from sticking against the ceramic shelf when it's hot, when it's all melted. You see all the scratches in there, so this shelf is no longer good. Sometimes you can re-use the kiln wash if there's no damage to it but this is too much.

    So, what we first do, I put on my dust mask because it does get pretty dusty. I have a standard scraper, you can get these at any hardware store and you basically scrape it all out. It's not much fun but you want to get it as even and as clean as possible. Now, if you don't scrape up the old kiln wash, you just build up new layers of kiln wash on top of it and eventually it will peal off of course at a moment that you don't want it to. So, this is pretty clean here and now we're going to put on the new kiln wash.

    It's a liquid, it comes in a powder and then you mix it with water, so you get a liquid that is kind of like whole milk and you want something that's thicker than water, but not so thick that you can't spread it out properly. What I like to see is that you can coat the whole length of the kiln shelf without having it dry up. See, it's drying up a little bit, so it could be a little bit wetter. You can just add water to it. Again, you want this coating to be as even as possible. Then, I go the other way too just to make sure that everything is covered and we have various shelves. We also have round ones that we use for making larger bowls that are little bit -- so you can get a larger diameter bowl on these shelves. But each shelf pretty much matches the size of your kiln. Here we go, we will measure, we do one more, okay.

    Now the shelf is very wet and before you can put your glass on, it needs to be totally dry. So, we often just dry it in the kiln, take it up to about 200 degrees, 250 degrees so it doesn't get too hot, too hot to put your glass on, but it still dries out all the water from the kiln wash. So I'll take it over there now. Now, at this point we've heated up the kiln shelf and you see the color change. It's now become like a light pink, that way you know it's all dry. It's still a little bit warm but I think, it's fine to put the glass on. So I have the square bowl and here it goes. Early, we've filled the kiln with a little more than just little six inch bowl.

    But it's very important to again hold the glass from the side, so that you're not putting extra fingerprints on there and also you want to put the glass exactly where you want it and put it down and not move it. Don't shove it around because you'll be scratching this delicate kiln wash and that will allow the glass to possibly touch the shelf and then it will stick to each other and you'll ruin both the shelf and your piece. So, that's not what you want. When you put these plugs back in and close the kiln door and in the next segment. We'll be talking about how to program the kiln, what sort of schedules to use and just a little bit more technical information about heating and cooling glass.