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I have a round piece that I'm getting ready to fire that has pattern bar inclusions. I have arranged them on the kiln shelf and capped the design with clear so the total thickness is now 6mm. I'll full fuse. I want to f and f to get the nice crisp lines, but like the look of a clear cap on something as nice as I hope this will turn out.

If I DO cap with clear, I'll have to dam it and was wondering just how 'tight' I have to have the fiber paper around the piece. Does it have to be supported at all points? Can I just wrap it snug and have it supported at a few points? I haven't done this with a circular piece and don't want to screw it up, if possible. Any advice would be appreciated!

Wrap it with about three layers of 1/8" fiber paper. I usually use scotch tape to make a long strip, wrap, pin the closing edge with a stainless dress-making pin, and then support the fiber paper here and there with a few pieces of kiln furniture.

Dana W.

Thanks. That sounds great. I'll give it a try.

3 layers is probably over kill. I also spray the inside of the 1/8th inch with mr97 so that I get no spikes that need grinding off. My other suggestion would be.....if you cap it in clear you arenprobably going to have quite a few bubbles. I would consider doing it in 2 steps....cap in second firing or use clear frit.

If you're not using frit, forget the mr97- just cut the strips 1/8" shorter than the glass stack.

Marty wrote:If you're not using frit, forget the mr97- just cut the strips 1/8" shorter than the glass stack.

Agreed.I don't usually have any issues with spikes on sheet glass.

My first layer of paper, against the glass, is usually Papyrus. This leaves a much smoother surface than the 1/8" fiber paper, so it's easier to coldwork.

Dana W.

agreed…..my mind was on scrap as that is what I was using today!!

Thanks so much everyone! This is done in only two firings. I guess I didn't make myself clear enough. I arrange the pattern bars, etc., on the kiln shelf and have an entire 3mm design layer.Cap that with clear. Fire. I now have a fully fused 6mm piece that I want to have the nice, crisp design layer on top. Instead of just flipping and firepolishing, I was thinking of capping THAT with clear. Now I'm wondering if I cap it with THIN clear if I need to dam it at all. Hmmm. What do you think about that?

In that situation I would not worry about damming the piece

Thanks. I think it's ready to go into the kiln today. I'll let you know how it turns out!

I don't get spikes against fiber paper unless I've got high glass flowing down the paper and leaving trails. So...I do my layups to avoid that situation. I don't really get the whole BN-spray-against-fiber-paper thing. The stuff isn't cheap and it won't really do much to reduce the fiber texture, the fiber paper's got a built-in release anyway, and it's just not that hard to knock off a few rough or sharp spots when you coldwork it.

If you do cap the underside with clear, make sure you've cleaned it well and you're not trapping firing residue inside the glass. You can sometimes increase the chance for bubbles and unwanted gunk in the glass. I don't think you need to dam as long as you use a thin piece of clear and you're careful with your schedule (i.e., process just long enough to fuse the cap and stop). You'll get a bit of spread at the edges but not enough to really hurt unless you've got a difficult color/pattern at the edges (some geometric thing in a really soft glass, such as a black and white checkerboard or something).

However...you're probably not going to distort the shape as much with a firepolish as you (potentially) could with full-fusing a clear cap. Unless there are issues you need to hide under the cap, I think I'd leave it as is, maybe do some surface smoothing on that underside, and firepolish.

I did not get a chance to fire it today. Probably a good thing. I really don't need to clear cap it to hide anything; I just wanted to give it a more substantial presence. Not really necessary. I actually ended up making it kinda narrow and oblong. I'm quite pleased with the piece so far. I'm leaning towards just cleaning up the bottom (soon to be the top) and firepolishing. I'll post a pic when it's finished. I do want to do something similar, but thicker. Have to think about how to accomplish that.

Thanks so much for all the help/ideas! I really do appreciate the input!

Okay, here's the piece that I want to flip and fire. Came out of the kiln this morn. Edges need to be worked on the WBS, but I'm leaning towards NOT capping with clear...

Don't do any more! It's very striking. Do the edges, but the overall impression is great. Jen

Cynthia......about the MR97 on fiber.......if someone has a small studio and only a small grinder.....and is doing let's say scrap melts ....the MR97 on the fiber paper makes a huge difference. I have done side by side tests on my birdbaths that are piles of scrap glass getting melted.......can't always keep the scrap away from the edges like you might want to with smaller frit. The unsprayed melt will pull down the paper making spikes. The sprayed slides right down and hasva very small amount if any. mR97 is not all that expensive when you know where to buy it. A 13 oz can lasts a long time. Just my 2 cents!

Thanks, Jen. I'm going to do some cold work, slump and leave it alone!

Laurie Spray wrote:Cynthia......about the MR97 on fiber.......if someone has a small studio and only a small grinder.....and is doing let's say scrap melts ....the MR97 on the fiber paper makes a huge difference. I have done side by side tests on my birdbaths that are piles of scrap glass getting melted.......can't always keep the scrap away from the edges like you might want to with smaller frit. The unsprayed melt will pull down the paper making spikes. The sprayed slides right down and hasva very small amount if any. mR97 is not all that expensive when you know where to buy it. A 13 oz can lasts a long time. Just my 2 cents!

No BN spray is as effective as planning your layup to cut down on subsequent coldwork. It's already very easy to spend a fortune on necessary glassmaking supplies, tools and equipment. I don't see the point of spending even more when you can change a process and accomplish the same result. Frankly, part of the fun of glassmaking (for me) is figuring out how to use stuff from the hardware or kitchen store instead of the glassmaking versions, which are generally sold at a premium. I mean, I've seen CMC solutions going for nearly $50/quart, which is outrageous when you consider that you can make your own for about $1.35/quart. I'm usually looking for a better ROI than that.

Let's say you can buy a can of MR-97 for about $21--the can says it will do 50 molds, so maybe that's 75 dam edges. A small edge grinder is around $80, roughly the cost of 4 cans, or about 300 edges. Will the grinder last for that many edge grinds? Most assuredly, and then some. The one I had probably got up to 2500 before I gave it to someone who, 4 years later, is still using it.

If you're just going to pile in scrap willy-nilly, nuke it and see what you get, yep, you will most likely get some spiking but hey--it's not fatal. I went for years with no grinders at all, doing what would now be called potmelts, and got along just fine that way. I used a pair of nippers and a coarse diamond pad on them...until I figured out that I could minimize or avoid spiking entirely by getting smarter about where I put the glass.

What Marty's suggesting works beautifully with flat sheet AND with potmelts (i.e., keep the paper at least 1/8 inch below the final level of the stack). If you've got a pile, keep the glass at least a half inch away from the dam, and it does about the same thing.