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Thin French Vanilla

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Thin French Vanilla

Postby Suzanne Chudnoff » Mon Mar 08, 2010 2:22 pm

I have made two pieces recently with thin french vanilla, one backed with clear and the other backed with dense white with clear sandwiched with in between. Both pieces came out with big splotchy areas. To me it looks like someone spilled oil on it (like a piece of white paper that had oil spilled on it). Could this be because the thin sheet had "very thin areas" that could not maintain an even color? It looks like a bad mistake, not the good kind. I was also unable to get a reaction using dense white frit and strips on the thin french vanilla. Could this also be a factor of the glass being too thin? I've used thin vanilla cut into frit and was able to get a reaction on dense white, so I figured it would work in reverse. I've attached a couple of pictures of the splotchy areas (hard to see in a picture so I hope these help).
FrenVan1_sm.jpg
FrenVan1_sm.jpg (17.14 KiB) Viewed 3319 times
FrenVan2_sm.jpg
FrenVan2_sm.jpg (16 KiB) Viewed 3316 times
My firing schedule was as follows: 1) 300, 250, hold 30 min. 2)500, 1480, hold 20 min. 3 9999,930, hold 1 hr 4) 150,700, no hold. I've used this schedule to get reactions of french vanilla frit on dense white and it's worked well. What gives?

Suzanne
Suzanne Chudnoff
 
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Re: Thin French Vanilla

Postby marykaynitchie » Mon Mar 08, 2010 2:50 pm

Dear Suzanne,

Alas, we know of the splotches in some French Vanilla sheets. We did extensive research on this glass for a customer who was using cases of it for a production line. It sometimes opalizes smoothly to a continuous color, but sometimes in areas it develops a marbled, slightly darker pattern. Our customer wanted us to either make that splotchiness go across the whole sheet, or have it disappear completely.

What we learned in our testing was this: we can't tell from the appearance of the cold sheet where/if the marbling is going to happen. We took whole sheets of French Vanilla, perfectly uniform in appearance, sliced them into 6 pieces and fired them, then rearranged them back into a whole sheet. Most of the sheet ended up smooth, but marbling happened in areas we could not predict. We also took sheets where the color was not uniform in the cold sheet, but when we fired the sheet, the color struck to a uniform, smooth French Vanilla.

Believe me, we understood the customer's need for a perfectly uniform French Vanilla, but we could not formulate it, and keep all the other characteristics the same. And we can't tell which sheets are going to behave uniformly, even by looking at them. French Vanilla is a beautiful, fickle, surprising glass. People usually don't notice the marbling if they are using it in fairly small pieces or on edge, but when used in a wide section, they are sometimes surprised by this characteristic.

Regarding the lack of reaction, I am not sure this is caused by the same phenomenon. In fact, I don't have personal experience working with a reaction between Dense White (still discontinued) and French Vanilla, but maybe other people have advice.

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

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Re: Thin French Vanilla

Postby Suzanne Chudnoff » Mon Mar 08, 2010 3:09 pm

Thank you Mary Kay for your timely response. Do the 3mm french vanilla mottle also, or is it just the thin sheets?
Suzanne Chudnoff
 
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Re: Thin French Vanilla

Postby marykaynitchie » Mon Mar 08, 2010 4:40 pm

Good question! Our tests were based on the 3mm sheets. I assume that the thin sheets would behave similarly.

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

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