Borax anti-devit side up versus side down

[Alexis Dinno]

Some questions.

I sometimes use the borax/water/detergent recipe to control devitrification. I work almost exclusively with float and float-compatible stuff. I find that application of this mixture (and then firing to above about 760ºC) gives a nice 'flowiness' to the glass in addition to/as part of how it prevents devitrification.

I have been warned about and have occasionally experienced the sticking of kilnwash and thinfire to glass if I put the devit-treated stuff face down. However, I have received one report from someone who has claimed not to have this stickiness problem with borax-based devit wash.

My anti-devit wash is completely dry before being laid out on the shelf.

My questions:

1. Are there temperatures at which such treated glass won't stick to either kilnwash or thinfire paper?

2. Are there formulations of kilnwash (e.g. extra emphasis on alumina hydrate, as opposed to clay) which will discourage this tendency to stick?

3. Suppose I treat the top of some glass with this solution, and then in a separate firing flip the glass, is there a danger of glass sticking to either kilnwash or thinfire?

4. Are there formulations of the solution itself which can discourage such sticking?

Thanks for your insights.

[Alexis Dinno]

3. Suppose I treat the top of some glass with this solution, and then in a separate firing flip the glass, is there a danger of glass sticking to either kilnwash or thinfire?

Gosh, what great questions Alexis! Why, thank you, Alexis.

Anyway, the insight I wanted to share regarding #3 is that firing float glass with the top painted with the anti-devit mixture to at least 750ºC (that's 1382ºF), and then subsequently firing to full fusing temps (840ºC/1544ºC) with the anti-devit side face down on Bullseye's thinfire does NOT result in material sticking to the glass. Woot!

Will hopefully get back to all y'alls on whether the same holds true for face down on kilnwash on a subsequent firing before too long.

[Bert Weiss]

Borax solution has never worked on the bottom for me. On the top, it requires a firing to at least 1400ºF.