Bullseye Thin Fire - Grrrr!

[LDGlass]

Anybody have any tips for using Thin Fire without getting scum on glass? This is true Bulleseye Thin Fire, not the economy crap. So far it works well with white opalescent glass. Clear, black, any translucent colors I get scum. Someone once told me to pre-fire it but then it turns to dust. I'm about ready to give it away. I like Papyros so much better. So if you have any suggestions or advice, I'd love to hear it!

[vblue]

I have been using the BE thin fire for years and never got any scum on the glass. Are you putting small kiln posts on the corners to keep it from rolling onto the glass?
Where is the scum appearing?

[Babette (Shawn)]

I recently had a problem with Bullseye thin fire paper leaving white scum on glass, where it had not before. I thought hard about what was happening and what had changed...the only thing I could think of was the change in weather; summer is over, the leaves are falling and it has started raining. We all know how awful thin fire paper gets if it gets wet, it leaves scum? Could there be some moisture in the thinfire, and/or my kiln? Or maybe I did not dry my glass off well enough? So I tried slowing down the beginning of my firing schedule to burn out any moisture in the paper or in my kiln. My new schedule: 50 degree/hr to 200 degrees, hold 20 minutes, I then fired the rest as normal. I had no scum. To be honest I am not 100% certain that I have found the solution, but it has worked twice now.

[LDGlass]

I appreciate the responses and suggestions! Thin Fire has never "rolled" for me. I used to have that problem with the economy shelf paper and in fact that was one reason I stopped using it and decided to spend the extra money on the Thin Fire. So I am really disappointed with it's performance. I could start my firing schedule slower but I am impatient when firing small pendant pieces. Now that I'm thinking about it, I wonder if weather is a factor and moisture? My studio is in our lower level so it might be a bit damp down there. I only use shelf paper when I don't feel recoating my shelf with kiln wash. Hmmmmm.... I don't know what the answer is.

[Barry Gitelson]

I have found that venting the kiln to 1000 degrees has helped.

[Morganica]

There's a whole bunch of info on this that you can find by searching for thinfire or fiber paper. I've seen this with more than just thinfire; it also can happen with casting plasters in the kiln, thicker fiberpaper or fiberboard.

Fresh refractory can outgas as the binders and other components burn off, and that seems to be what contaminates the glass. To alleviate, I do what Barry does, i.e., vent the kiln to somewhere between 900 and 1100F (depending on when I'm going to bed). Venting gives the gasses/airborne particulates somewhere else to settle, so you get less gunk on the glass.

I also make sure that any kilnwash applications (on a slumping mold or shelf) are dry (and preferably fired at least once) before a piece goes in for final firing. And I make sure that I only use other refractories like plaster or fiber paper in firings where the glass will be sandblasted or coldworked. I keep it out of the kiln for "final" firings.

That seems to do the trick for me. Different glass types and colors seem to have different sensitivities to "scumming" (I think it's really mild devit, myself). Some people say they've never had this happen, and so it's either a practices issue, or possibly it's so common nobody really sees it as a problem. That latter happened to me; I never, ever, ever saw any kind of deposit on the glass and didn't know what all these "scum" people were talking about...until I slumped some uncoldworked pieces (I generally coldwork everything pretty extensively. The difference between the blasted and non-blasted pieces was so obvious I've been experimenting with how to cause/alleviate it ever since.

[AmySkewed]

How high are you firing? I have found that if the glass is moving on the paper (think pot melt) it will get scummy as it moves. If the base layer is stable I have never had a problem with thinfire or Papyros

[Valerie Adams]

I've had trouble with Thinfire ever since I switched to Tekta for my clear cap. I used to use Uro Machine Rolled and barely even cleaned it, and it was clear and trouble-free.
As soon as I bought a case of Tekta my troubles began. I've done all the different methods of cleaning, new lint-free cloths, different cleansers, etc. The only thing that has alleviated the scummy look is eliminating Thinfire. I also suspect that the newer Thinfire, with the logo on the back, is worse than the older, blank kind.

I thought of going back to Uro, but I get nicer champagne bubbles with Tekta due to the texture it has. So now, if I'm using Thinfire for any reason, I make sure my Tekta is used as the base.

[Laurie Spray]

I use thinfire with the logo daily....never vent my Genesis......use double rolled Uro clear and have never had a problem. Hmmmmmm. I love thinfire on it's huge rolls......


Have you used any reactive glass recently in your kilns?

[LDGlass]

I sure do appreciate all the great responses. It's weird because it doesn't happen all the time. Maybe its just certain types/colors of glass. I don't use it at temps higher than 1470-1480. I vent the kiln. I never use it with my final firing. I'm going to do some experimenting this weekend and we will see how it goes. Personally I am wondering if my climate (humid in the summer, damp in the winter) is having something to do with it. I do work in the basement level of our home and think maybe that's a factor. I'll keep chugging along and trying different things. Now I seem to be on a mission to figure out what the issue really is.

[Valerie Adams]

Read through Bullseye's forum with a search of Tekta + Devit; there's plenty of discussion about it there.

http://www.bullseyeglass.com/search.htm ... ekta+devit