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Mullite dams

Posted: Wed Dec 24, 2003 3:05 pm
by Geri Comstock
A while ago there was a post somewhere about someone who makes mullite damns longer than the ones made by BE. I have a the BE ones, which work great, but they aren't long enough for the piece I'm making.

Does anyone have a source for mullite dams longer than 10"? I'm looking for something about 15-20".

Thanks.

Geri

Posted: Wed Dec 24, 2003 3:14 pm
by Brad Walker
Seattle Pottery Supply has these, I believe.

But if it were me, I'd just buy a kiln shelf and cut it up with a tile saw. Cheaper and you get exactly the size you want. Some places will also sell broken shelves at a discount.

Posted: Wed Dec 24, 2003 3:44 pm
by Tony Smith
Hi Geri

It was a guy in Oregon. John Groth

Waterjet Design 503-615-0144

Tony

Re: Mullite dams

Posted: Wed Dec 24, 2003 4:16 pm
by Bert Weiss
Geri Comstock wrote:A while ago there was a post somewhere about someone who makes mullite damns longer than the ones made by BE. I have a the BE ones, which work great, but they aren't long enough for the piece I'm making.

Does anyone have a source for mullite dams longer than 10"? I'm looking for something about 15-20".

Thanks.

Geri
What about using fiber board for dams. I recently saw some dams at the studio of a famous glass artist and they were made with fiber paper and stick pins on vermiculite board. Apparently it doesn't take much.

Posted: Wed Dec 24, 2003 4:22 pm
by Bruce Larion
What Brad suggested does work really well. The local ceramic store was moving to a new location and in the clean up of storage areas they had almost 10 partially broken shelves which they were happy to let me haul away for free. I used my tile saw to "slice" a few up at various lengths and widths. Have used them to dam pieces as well as making pattern bars. Filled my need and fit my budget. Spent a couple dollars on a thank you card was all.

Mullite Dams

Posted: Wed Dec 24, 2003 6:13 pm
by Harry
Geri, Here is the post I think you are referring to.
Mullite Dams, 1 1/2" x1", 24"-$8: 20"- $7.50: 18"- $7. Other sizes available. All dams cut to the size you want.
Call John at Water Jet Design 503-615-0144
Harry

Posted: Wed Dec 24, 2003 6:16 pm
by Geri Comstock
Thanks, guys. That's the information I was looking for.

Geri

Re: Mullite dams

Posted: Wed Dec 24, 2003 6:52 pm
by Marty
Bert Weiss wrote:What about using fiber board for dams. I recently saw some dams at the studio of a famous glass artist and they were made with fiber paper and stick pins on vermiculite board. Apparently it doesn't take much.
Very funny, Bert. Actually, strips of rigidized board work well, and if you're firing on verm. or fiber board, you can use straight pins to hold them in place. The fiber paper strips work by themselves for round set-ups (again with the pins) but need a rigid backup for straight lines.

Posted: Wed Dec 24, 2003 7:10 pm
by Geri Comstock
LOL. When I grow up I wanna be just like Famous Marty. I'll use that technique then.

But for now, I found some old kiln shelves I thought I'd thrown away years ago and cut some nice long dams from them. Cutting those 24" long by 1" thick Thorley shelves was a bit of a challenge for my poor saw. So, for those of you who cut your own dams, here's another question...

If the cut edge isn't perfectly flat, what do you do to smooth it flat? My tile saw wasn't really thrilled about cutting the 1" thick Thorley's and the edges aren't as smooth as I'd like them to be. I'd like to get them smooth so they sit level and flat. Or doesn't it matter all that much?

The .75" thick shelves were a breeze for my saw to cut, but they aren't as long as the 1" thick ones.

Covered with mullite slurry and water -

Geri

both sides are ... crooked...right?

Posted: Wed Dec 24, 2003 10:23 pm
by Cheryl
Otherwise you can just use the other side. I've sanded mullite with regular sanding paper.If you use fiber paper on the side of the dam, the exactness doesn't seem to matter.

Posted: Thu Dec 25, 2003 12:37 am
by Ron Coleman
Geri

I had an old warped shelf cut up at Lowes. I used my flat lap grinder to flatten one face, one edge and one end. Mullite is soft and grinds easily.

Ron

Posted: Thu Dec 25, 2003 12:39 pm
by Marty
Geri- once you've got the rough strips cut, set the fence a little closer and run them through again. And they don't have to be absolutly flat- the paper (you are using paper?) will take up the slack. Marty

Posted: Thu Dec 25, 2003 4:21 pm
by Geri Comstock
Urk. Well, so far I haven't been using paper and it's worked just fine because I've kilnwashed the dams. But last night 2 of the new dams fell over and unkilnwashed mullite ended up next to the glass and left me with a cracked piece. I either have to brace the dams or use paper in the future.

Oh well...Live and learn. So it goes...

Geri

Posted: Thu Dec 25, 2003 5:18 pm
by Jeri D
I am using "Famous Marty"s " technique for the first time . I love being able to lay out my design, actually playing with a variation of yours Marty,
on the board. The only problem is who am going to get to carry it to the kiln for me. the board with the glass weighs a bloody ton for a pipsqueak like me
Tiny Timette

Posted: Thu Dec 25, 2003 9:22 pm
by Tony Smith
Geri Comstock wrote:Urk. Well, so far I haven't been using paper and it's worked just fine because I've kilnwashed the dams. But last night 2 of the new dams fell over and unkilnwashed mullite ended up next to the glass and left me with a cracked piece. I either have to brace the dams or use paper in the future.

Oh well...Live and learn. So it goes...

Geri
Geri,

The dams that I got from John at WaterJet Design are pretty hefty. They are about 1½ inches tall by an inch thick and they won't go anywhere after you get them in position.

Tony

Posted: Thu Dec 25, 2003 9:55 pm
by Tony Serviente
I've cut 3/4" mullite shelves with a circular saw, and using a straight edge guide you can parallelisize it nicely. I use the cheapest plywood blades I can get, set up a shop vac to suck up the dust, wear a respirator, glasses, and ear protectors then let the good times roll. The blades don't much like it but they get to retire early.

Posted: Thu Dec 25, 2003 10:07 pm
by Tony Smith
They cut great with a tile saw... like butter. No dust, no mess, no trashed blade. Just drain the mullite slurry from the basin when you're done.

Tony

Hefty

Posted: Thu Dec 25, 2003 10:11 pm
by Valerie
If they are that hefty ...I suspect the shipping costs are too eh?

Re: Hefty

Posted: Fri Dec 26, 2003 7:18 am
by Tony Smith
Valerie wrote:If they are that hefty ...I suspect the shipping costs are too eh?
Oh yeah! When I got the package, I thought it was something good like gold bullion. It's amazing how heavy the mullite shelf is when it's packaged in a compact 3x4x20" package. But it was still worth it.

Tony