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Slumping small bowls

Posted: Sun May 19, 2013 8:41 am
by Cate G
I'm having an awful time trying to slump into small ceramic bowl molds, from 5 1/2" to 7 1/2" sizes. Is it that the smaller the mold, the longer it takes to slump? They also seem to not slump evenly ( my kiln is level but I didn't think to level the molds ) I have 2 kilns, a 42X27 oval and an 18" round. I usually like to slump a bunch of stuff at one time in the oval, but should I slump these small pieces seperately? I use a schedule to accomodate the bigger pieces:
150 to 1000 hold 10
200 to 1200 watch until slumped
Then anneal
Thanks, Cate

Re: Slumping small bowls

Posted: Sun May 19, 2013 9:23 am
by DonMcClennen
Smaller, deeper, takes longer...use smaller kiln if you can and do separately.

Re: Slumping small bowls

Posted: Sun May 19, 2013 9:25 am
by Mike Jordan
I've been doing small bowls using the Bullseye cone mold and other than the very first one being a little off around the lip I haven't had any problems. I checked the level of the mold with the glass sitting on top of the mold to make sure it was level and then had to be careful that the glass sat on the mold evenly all the way around. I have the shelf and mold already in the kiln and then put the glass on top and just have to feel that it is even around the whole circumference. I have a deep kiln and can't see very well. I'm using Bullseye glass and their suggested scheduled worked fine for single layer glass but I tweaked it to give it a bit more time for double thickness glass.

Image

Mike

Re: Slumping small bowls

Posted: Sun May 19, 2013 10:14 am
by Cate G
Thanks, Don and Mike. I will slump them in the smaller kiln next time. Mike, do you know what the Bullseye schedule is? I am having a hard time accessing info on the Bullseye site from my 3g tablet. It kicks me off the site for some reason. I was thinking 400 to 1000 and then 100 to 1250 and watch (hold for maybe 30 if it gets up that high). I was going to use single layer glass for these.
Cate

Re: Slumping small bowls

Posted: Sun May 19, 2013 1:09 pm
by Mike Jordan
Cate, their recommended slump schedule is:
300 to 1225 hold 85
9999 to 900 hold 60
100 to 700 hold 0
300 to 300 hold 0

Keep in mind that this is for Bullseye glass and their kiln although the same schedule did work in my Skutt kiln.

Good luck.

Mike

Re: Slumping small bowls

Posted: Sun May 19, 2013 2:10 pm
by Cate G
Thanks Mike. I have 2 ready to go and I will try it tomorrow. It' a lot better schedule than the one I was going to use ;-).
Cate

Re: Slumping small bowls

Posted: Mon May 20, 2013 10:07 pm
by lorimendenhall
I have a shallow 6" heart bowl that I slump successfully with this schedule:
300/1100/20
150/1250/20
400/960/60
300/100/0

Re: Slumping small bowls

Posted: Tue May 21, 2013 2:05 am
by Stephen Richard
I have found on small deep moulds, it is more successful if the glass is cut to be within the mould rather than on top of the edge. Also slow rises in temperature, low slumping temperature, and long soaks more successful than quick, high and short.

Re: Slumping small bowls

Posted: Wed May 22, 2013 3:28 am
by S.TImmerman
What you have is their cone mold.. Here is BE"S Tech sheets on this exact mold http://www.bullseyeglass.com/methods-id ... -bowl.html