WarmGlass.com

I asked yesterday about re-firing a box I had made.
I then viewed some BE videos and came up with a schedule I thought made sense... at the time.
Now, it looks very very strange:

100 d to 200 hold 6 hr
100 d to 1250 hold 2 hr
600 d to 1525 hold 1 hr
AFAP to 900 hold 6 hr
12 d to 800 hold 5 min
22 d to 700 hold 5 min
72 d to 70

I know this made sense last night when I set it up, but I think my brain was asleep.

I'm not sure what you mean by a 'box' but that 6 hour hold at 200° seems like a big waste of 6 hours to me!

I agree, Velerie..., I don't know what I was thinking.
How about the rest of the schedule.

The box is one I made with this mold:
http://www.colourdeverre.com/product_de ... 4&id=16383

Sides are about 2.5 inches tall and no more than .75 inch wide at any point.

Loraine

Did you check out this schedule?
http://www.colourdeverre.com/img/projects/BoxBasics.pdf

Thanks, Valerie.
Am I mistaken thinking that since this piece had already been completely fused and annealed that it would require a very different schedule than the original one I used?
Loraine

I don't have any experience with those little casting molds so someone else may chime in. If I'm refiring something, I'll usually ramp a little slower and reduce my top temperature a bit to avoid excessive heat work. It also depends on what you're trying to accomplish with this firing.

I'm guessing the hold at 200 is for when you are doing a casting in a plaster mold so that the mold can dry out. If you are using a ceramic mold, it wouldn't apply. I would do just what Valerie recommended and go slower on the way up.

Barb

Barb is right; that looks like a schedule for casting glass in a plaster mold. The hold at 200 (although that's a bit low) is a drying segment, intended to slowly evaporate the water in the mold. Colour de Verre molds (I just won a couple at the glass guild vendor fair so I'll be trying them out) are ceramic, so no drying segment is necessary (I suppose you might do that to dry out wet kilnwash but I wouldn't do it with glass in the mold and it would take a fraction of that time)

I just reread and see that you're refiring a piece cast in that mold. Normally I'd say yep, creep up..but the glass is in the mold that gives it shape. If it cracks, you don't care--it will heal during the firing. The only worry would be if the upramp was sharp enough to jar or overturn the mold, so I'd probably go up about 200dph to 1200F.

At that point I'd probably drop down to 100 dph, creep up to 1240 and hang out there for awhile. How long depends on the effect you want. In a plaster casting with billet or bigger chunks of glass, you need a nice, long bubble squeeze to ensure you've pushed out as much air as possible, and increase the chances of a bubble-free casting. OTOH, tiny bubbles are what give pate de verre its gorgeous, jadelike quality, so you don't need such a long bubble squeeze. You just want enough squeeze to get the frit to settle in.

But in your case, there's no need for a bubble squeeze unless you're adding more glass. Even then, I don't think it needs to be more than 30 minutes--you're not adding that much glass.

The process segment will depend on what you're trying to do with the refire. If you're mending a crack or wanting more heatwork so you'll get better detail or adding more glass, well, those will take different amounts of time.

As for the rest, not sure why you'd have holds at each of the downramps, and without knowing the thickness I have no idea how slow the anneal should be. The mold I have looks as if it's about a half-inch at the thickest part, so I'll start with a half inch schedule and work my way up depending on variations in thickness.

Hope that helps.

Thank you thank you...,
I will print and save these comments in my casting folder.
There is a lot of information here.
I appreciate you all imenslely immensly emennsley ( boy do I wish is could spell)
Loraine