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I have a lot of ceramic and porcelain tiles laying around. can i use them as dams to dam glass to keep it square? would i take the glaze off or place it so the glaze side is on the outside? using fiber paper to cover the sides i assume. I have a lot of porcelain bowls and interesting plates also. If i took the glaze of could i slump in it? porcelain cracks at about 2000F degrees while slumping takes place at 1200F so i imagine im fine. Id rather ask a silly question then make a mistake and ruin the glass i just bought. money is TIGHT and i cant afford to be buying dams when i have so many ceramic tiles laying around. Thanks

I used some porcelain tiles as supports for a pot melt a few times and they warped during firing. You want your dams to stay straight and true, so based on my experience, I wouldn't use them for dams. As for the bowls as molds, I use all sorts of found ceramic and porcelain materials as molds. I figure the worst that can happen is breakage.

so what would you recommend for dams? i see a lot of different kinds from bricks to people cutting kiln shelves. Fiber board seems the cheapest option but i imagine its doesnt last and makes a mess. if im going to buy something im probably going to get another kiln shelf and cut it. seems cheaper then buying a bunch of different sizes. Wait would bricks work? just plain old buy at home depot bricks?

Ask around for broken kiln shelves. Cut them up.

I cut up a 12 x 12" ceramic tile into 1 1/2 strips to use as supports. They warped also, but I also use them as dams when I just want to hold fiber paper in place. I then cut up a small kiln shelf 10 x 10" - it does the job without the warping. If you have a lot, you can use them once, then toss them. Mine warped when I used them as supports (bent in the center); maybe if they are laid flat, the warping wouldn't occur. Good luck!

Patty

Cut up kiln shelves are better than any other option. Heavier, straighter, better able to take the heat on repeated firings. And can be cut to whatever size you want.

If you can't find a broken shelf, cut up a new one. Still the best and probably least expensive option.

The only hitch is that you need a tile saw to cut them.

A VERY inexpensive new kiln shelf option is to look on Amazon for cheap pizza stones, and buy those and cut them up. I bought three 13", and cut one up for dams, and all have been used several times and work perfectly.

The $12 I spent on each pizza stone was better than the $30 for a kiln shelf. The one's I bought, you can only use one side, as the other side has a weird raised texture (like a crop circle!) and they're maybe a 1/16 thinner, but work absolutely perfectly.

Unfortunately, I seem to have an never ending supply of broken kiln shelves. Last month I had another series of break downs - 3 shelves in an week.

Stop by a pottery supply house and ask about broken kiln shelves. They usually have a bunch and sell them at big discounts.

Tony

Oh dear Stephen, what are you doing to your shelves. What a sad thing. Are there Gremlins in your studio .

I've used red paving bricks as dams and they are stable up to 1700 degrees at least. They must be the baked clay type, not concrete. Downside is that they are usually no longer than 9"

On a closely related topic, what would happen if you kiln washed common house bricks and used those as dams?

Too porous, just like vermiculite board.
Assuming the bricks were dry, I'd use them with fiber paper, not kiln wash.

twin vision glass wrote:Oh dear Stephen, what are you doing to your shelves. What a sad thing. Are there Gremlins in your studio .

No just a stupid user!

I agree with Marty. Bricks are best used as props and weights rather than the dams themselves

Personally i like using stainless steel best. Big surprise there, huh! I can fit so much more in the kiln too. In a class making reverse casting i took my own formers to the class. While everyone else was stuggling with dams and supports etc i just put in the stainless and built the piece in 2 min. Gotta love it!

Do you have some sort of system to make it self supporting?

I got some thick-walled stainless square stock, 12-inch lengths of square pipe with walls about 2mm thick, in diameters from 1 inch to 4 inches. I originally got it for making square murrini cane--you line it with fiber paper, fill it with a pattern of stringer and fire upright in the kiln to make picture cane.

But it works beautifully as a dam or as weights in the kiln, too. Very maneuverable, and it's heavy enough that it doesn't need backup.

I'd be careful with red brick on the first firing. It is frequently stored outside, and if it's got a lot of stored moisture it could crack/pop off/explode. That might embed brick in your work. Might want to prefire brick by itself, just to make sure.

I used one of Laurie Spray's stainless steel squares instead of dams for an 8 x 8 strip construction project with fiber paper around the inside of the stainless steel. I built the strip construction project in my studio directly on a newly washed kiln shelf, then transferred it to the kiln in the garage. Very easy. Minimal needles.
Susan

I keep meaning to get a blog post of some sort written up about this, but, in regards to using fiber paper when damming...

Several times now I have cut thin strips of Papyros paper, cellophane-taped the ends together to make a long strip, wrapped it around the glass for several layers, then used a layer of fiber paper around that before damming (either with ceramic strips or using a stainless ring). By using the Papyros, the edges of the glass are much smoother so they require less coldworking. That's the one thing I don't like about damming -- the "popcorn" on the edges from the fiber paper. The edges are usually cold-worked anyway, but it requires far less work if you start with a smoother surface .

I've had good success with this so far. I would assume that ThinFire would not hold up like the Papyros does, but I haven't tried it.

Dana W.