Page 1 of 1
Re: Schedule assistance - piece is in the kiln
Posted: Sun Feb 17, 2008 7:57 pm
by Faye Malench
If it were layer on layer, I know you'd slow the schedule btween 1050-ish to 1250-ish. Here i'ts not like you are sealing off the edges and trapping bubbles but I'm thinking you are going to get some big ones anyway. Can you ramp up higher and then drop back to a hold at 1500-ish to dissipate bubbles? Think how the potmelts go -- a hold at 1500 helps the bubbles rise and break. Or maybe make your top temp around 1500 for a bit? I'm guessing here but there's a lot of airspace betweeen those murrines that can trap. This piece is thicker than some of the others that are similar in design. I know you don't want the edges of the "boxes" to blur much but I'm thinking trapped air will give you pencil eraser bubbles. Hope someone else speaks up before it advances too far. This is not so different than the Twin's cut color bars setup.
Re: Schedule assistance - piece is in the kiln
Posted: Sun Feb 17, 2008 8:28 pm
by Barbara Muth
Toni Johnson wrote:Thanks, Bert. With the 50 dph ramp up, I was thinking that would pretty much take care of the squeeze with the hold to help finish. I can drop that to 1200. The components really are varying heights from 1/4" to 5/8" to 1".
Toni
Toni, with the 50 dph ramp you don't need a bubble squeeze soak at all. I have eliminated the soaks from my schedules without any adverse effects.
However, if you want to know when you need a squeeze in your kiln, run the "know your kiln" test to see when the glass starts slumpiong. That would be when you really need the soak if you are going to soak.
In terms of layup and avoiding bubbles, I think I might have fused the first two layers first without the top billets. I'd be afraid of trapping air between the billets and the elements. But since they have varying heights, I'm not sure how I would solve that. Well test away till you get the method right!
Barbara
Re: Schedule assistance - piece is in the kiln
Posted: Sun Feb 17, 2008 9:36 pm
by Toni Johnson
Barbara,
Well, I do most of my slumping at 1150 with a long hold. Believe me I thought about doing this in steps, but with the different layers I couldn't do that. Well I guess I could have cut a whole bunch of little clear squares and built up the levels so they were even and fired it and then added the billets in the next step. Okay, next time.
The kiln is at 1150 or so right now and no movement so far.
Thanks,
Toni