Overglaze vs Super spray for Devitrification

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tgotch
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Overglaze vs Super spray for Devitrification

Post by tgotch »

I sometimes get devitrification on bottles I slump and fuse. I have been using the recipe of borax and water. Seems to work ok, but thinner and brown glass is more prone to devit it seems.

I have been hearing reading about Super Spray A and Clear Coat Overglaze. It's my understanding that the Warm Glass recipe with Borax is essentially the same as Super Spray. I also heard someone using Clear Coat Overglaze which they say helps control devit better. Any thoughts on Overglaze vs. Superspray vs. Borax recipe?
Barry Kaiser
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Re: Overglaze vs Super spray for Devitrification

Post by Barry Kaiser »

Clear Coat Overglaze is the same as borax based Devit agent.
Spray A contains low melt glass to prevent devit.

I use a home made borax agent. It is ultra-cheap and Works beautifully. I use it an all ground edges.

Someone else chime in here about bottles or found glass. That could well be a different situation.

Barry
Valerie Adams
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Re: Overglaze vs Super spray for Devitrification

Post by Valerie Adams »

I've had a strict 'no bottle slumping' rule in my studio for the past 13 years.

But recently, a very dear friend requested that I slump a special bottle. I swore her to secrecy, did a little research, sprayed it with SuperSpray, and flattened. The damn thing turned out so well that she sent me another bottle. I gritted my teeth and repeated the process, with great results. Spurred on, she then sent me an anniversary celebration champagne bottle with painted enamel flowers and gold accents. Once again, turned out perfectly. When she reminded me that she had connections with a large, local brewery and could 'hook you up as their bottle flattener' I put a stop to the nonsense, sending her to another studio. :twisted:

So, in my very limited experience, SuperSpray does what it says it'll do.
Judd
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Re: Overglaze vs Super spray for Devitrification

Post by Judd »

You're getting devit on brown glass? I get it on blue occasionally. Are you sure you're cleaning the bottles thoroughly?
tgotch
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Re: Overglaze vs Super spray for Devitrification

Post by tgotch »

I get all the label residue off the bottles, wash them, then wipe them thoroughly with 91% alcohol. They are spotless. I then spray with my borax mix(wipe it around with my finger or brush), dry, then put in kiln.

I haven't done much with blue bottles yet...

I have noticed green bottles almost always turn out great. I also have brown/amber bottles that are thick, and almost always turn out great. I have been slumping some thinner brown/amber wine bottles, and have been experiencing ~40-50% of the bottles have devit, many times near the bottom. This same color bottle with thicker walled glass as I mentioned does not get devit, but the thinner does...
Judd
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Re: Overglaze vs Super spray for Devitrification

Post by Judd »

Are you firing too hot or too long? Just a thought.
tgotch
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Re: Overglaze vs Super spray for Devitrification

Post by tgotch »

Judd wrote:Are you firing too hot or too long? Just a thought.
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rosanna gusler
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Re: Overglaze vs Super spray for Devitrification

Post by rosanna gusler »

i find that most devit problems can be eliminayed by venting to 1000f. i hold for 20 or so there as well. r.
artist, owner of wanchese art studio, marine finisher
Peter Angel
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Re: Overglaze vs Super spray for Devitrification

Post by Peter Angel »

rosanna gusler wrote:i find that most devit problems can be eliminayed by venting to 1000f. i hold for 20 or so there as well. r.
Thanks Rosanna.

Just curious - What happens at 1000F that requires venting?
Peter Angel
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rosanna gusler
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Re: Overglaze vs Super spray for Devitrification

Post by rosanna gusler »

Venting the kiln while heating lets out the 'fumes ' from anything organic out. Holding makes sure the whole kiln is up to temp. R.
artist, owner of wanchese art studio, marine finisher
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