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Cooling small glass pieces - AFAP?

Posted: Mon Mar 28, 2016 3:08 am
by helenM
I've been using the recommended schedule for firing Bullseye glass in a Paragon SC2 kiln (found on the warm glass site uk). This has been working very well for me (reduced the top temp slightly for squarer edges):

1. rate 400F/222C, temp 1250F/677C, hold 30min
2. 600F/333C, 1445F/785C , 10
3. 999F/999C, 900F/482C, 60
4. 150F/83C, 700F/371C End

I've read a couple of places that for small pieces of glass like pendants for jewellery or frit balls (e.g. 6mm thick glass, maximum 4cm wide, often less). So I was wondering do I need step 4 for small pieces? Can the program end at step 2 and then just let the kiln cool naturally? I assume I need step 3 to anneal the glass - or maybe I don't?

Re: Cooling small glass pieces - AFAP?

Posted: Mon Mar 28, 2016 8:30 am
by Bert Weiss
It is true that pieces under an inch in diameter will anneal faster than pieces with larger mass. What would you actually gain by eliminating your 4th step? The glass is always hotter than the air during the cool down. I don't know if you can get away with that or not. Look at tutorials by Barry Kaiser. He specializes in pendant sized pieces.

Re: Cooling small glass pieces - AFAP?

Posted: Mon Mar 28, 2016 2:57 pm
by JestersBaubles
When I am fusing simple small pieces (1" cabs, frit balls) in my SC2, I will ramp anywhere from 500 to 1500 deg/hr to the top temp, hold, and turn off.

Works for me, YMMV.
Dana W.

Re: Cooling small glass pieces - AFAP?

Posted: Mon Mar 28, 2016 10:11 pm
by jim simmons
JestersBaubles wrote:When I am fusing simple small pieces (1" cabs, frit balls) in my SC2, I will ramp anywhere from 500 to 1500 deg/hr to the top temp, hold, and turn off.

Works for me, YMMV.
Dana W.

Me to also :>)

Re: Cooling small glass pieces - AFAP?

Posted: Tue Mar 29, 2016 7:19 pm
by Valerie Adams
I'm with the two above who skip segments 3 & 4.

Re: Cooling small glass pieces - AFAP?

Posted: Fri Apr 01, 2016 2:10 pm
by helenM
Thanks very much everyone. I'm a bit nervous to try skipping the steps 3&4 in case pieces crack - but will test it out sometime - you never know till you try:)

Re: Cooling small glass pieces - AFAP?

Posted: Tue Apr 05, 2016 12:55 pm
by Barry Kaiser
Small pieces that don't need bubble squeeze:
AFAP to 1250°F hold 20 (just a stabilizing hold)
AFAP to top temperature (depends on kiln. I use 1475-1500 for final fuse) hold 12
Vent kiln to 900°
When temp rebounds to 1100 or so, vent a second time to 900. Close kiln until temp reaches 500. open kiln and take out when pieces can be handled.

Has worked every time on pieces 2x2 or less.

Barry

Re: Cooling small glass pieces - AFAP?

Posted: Thu May 19, 2016 2:35 pm
by Thomas Decker
I Have a firebox 8 with out a fancy controller, for small pieces I just ramp it up hold and turn it off . It naturally cools down so slow that it has never been an issue.