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Help please! My first Devit experience....i think....

Posted: Thu Sep 11, 2003 12:11 pm
by Janz
This is so ironic....I had just said last night how lucky I was that this had never happend to me.

Yesterday I fired a leaf between 2 scrap Sys. 96, and some dried flowers as well. I decided to throw in some regular Spectrum & Kokomo & Dragon Art scrap I had lying around to make some neat beads.
The leaf made a big crusty bubble, and the glass looks etched.... most of the "beads" look etched too....I don't know if this is devit. I've seen scummy looking stuff, but this looks and feels acid etched. It happend almost exclusivly to the opals.
Could this be burn off from the leaf? some gas or something? I left my peephole open. Or is this what major devit. looks like?
Thanks for any help.
Jan

Posted: Thu Sep 11, 2003 12:20 pm
by charlie
regular spectrum and kokomo devit terribly, especially opals. i've had some kokomo literally fall apart into dust after firing, but it was a 4 color mixture. i haven't even had good luck with borax spray on regular spectrum.

Posted: Thu Sep 11, 2003 12:23 pm
by Bob
Hi Janz,

Yup, it sounds like devitrification. Your observation that the scummy finish is most common on the opal glasses rings true. Opals are particularly prone to devit. Also, the chemistry of glasses made for fusing has been formaulated to minimize devitrification. If the Spectrum, Kokomo and other "scrap" glasses that you included are non fusing then they might be more prone to devitrification.

Cheers,

Bob

Posted: Thu Sep 11, 2003 12:43 pm
by lissa
Do you prefer borax to super spray or the like? I understand how they work differently, I am just wondering why folks chose one over the other as the desired results are the same.

lissa.

Posted: Thu Sep 11, 2003 12:49 pm
by charlie
lissa wrote:Do you prefer borax to super spray or the like? I understand how they work differently, I am just wondering why folks chose one over the other as the desired results are the same.

lissa.
borax is cheap, i can buy a lifetime supply in one box in the supermarket, easy to mix and apply from a hand spray bottle, and doesn't have any lead.

Posted: Thu Sep 11, 2003 2:28 pm
by Janz
Thanks....

I think they look pretty cool despite the devit.
They're gonna make some amazing mosaics one day.
If I ever get off all the kiln wash, that is.

Thanks again,
Jan

Re: Help please! My first Devit experience....i think....

Posted: Thu Sep 11, 2003 4:42 pm
by Brian and Jenny Blanthorn
Janz wrote:This is so ironic....I had just said last night how lucky I was that this had never happend to me.

Yesterday I fired a leaf between 2 scrap Sys. 96, and some dried flowers as well. I decided to throw in some regular Spectrum & Kokomo & Dragon Art scrap I had lying around to make some neat beads.
The leaf made a big crusty bubble, and the glass looks etched.... most of the "beads" look etched too....I don't know if this is devit. I've seen scummy looking stuff, but this looks and feels acid etched. It happend almost exclusivly to the opals.
Could this be burn off from the leaf? some gas or something? I left my peephole open. Or is this what major devit. looks like?
Thanks for any help.
Jan
If U wana bit of fun U will find something about devit in the archives

In brief use some anti devit stuff

Keep temp low and creap up 2 temp

Or zap up fast n crash cool

There is lots more

Brian

Posted: Thu Sep 11, 2003 6:31 pm
by Joanne Owsley
[quote="Bob"]Hi Janz,

Yup, it sounds like devitrification. Your observation that the scummy finish is most common on the opal glasses rings true. Opals are particularly prone to devit. Also, the chemistry of glasses made for fusing has been formaulated to minimize devitrification. If the Spectrum, Kokomo and other "scrap" glasses that you included are non fusing then they might be more prone to devitrification.

Cheers,

Bob[/quote]

I have experienced the "Opals are particualarly prone to devit" thing myself. I guess I just don't understand the chemistry of devitrification well enough though. How does having regular spectrum in the kiln with Sys 96 make the S96 devitrify? Is it kinda like making rock candy? Once the crystals start growing, they don't care what they grow on?

Posted: Fri Sep 12, 2003 4:02 am
by Brian and Jenny Blanthorn
Glassyeyed wrote:
Bob wrote:Hi Janz,

Yup, it sounds like devitrification. Your observation that the scummy finish is most common on the opal glasses rings true. Opals are particularly prone to devit. Also, the chemistry of glasses made for fusing has been formaulated to minimize devitrification. If the Spectrum, Kokomo and other "scrap" glasses that you included are non fusing then they might be more prone to devitrification.

Cheers,

Bob
I have experienced the "Opals are particualarly prone to devit" thing myself. I guess I just don't understand the chemistry of devitrification well enough though. How does having regular spectrum in the kiln with Sys 96 make the S96 devitrify? Is it kinda like making rock candy? Once the crystals start growing, they don't care what they grow on?
Opals can have stuff in em which makes em opal the devit grows from this growth point is called a neucleation point

Brian

Posted: Fri Sep 12, 2003 9:42 am
by Bob
How does having regular spectrum in the kiln with Sys 96 make the S96 devitrify?

Hi Glasseyed,

The regular Spectrum is more prone to devitrifying than System 96. However having regular Spectrum in the kiln will not cause the System 96 devitrify. The devitrification is caused by the growth of microscopic crystals on the surface of the glass... this is dependant on the glass chemistry, temperature and time.

Cheers,

Bob

Posted: Sat Sep 13, 2003 12:50 am
by Lynne Chappell
Yes, but her System 96 pieces devitrified as well (I think). Could the burning leaf cause such problems?

Posted: Sat Sep 13, 2003 12:10 pm
by Janz
The more I think about it, I don't think the leaf was responsible for any gas emission type stuff.... There's a huge bubble in the glass, if gas had esacped wouldn't the bubble have a hole, or something?