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A few years ago (could be longer, the way my memory is) there was a new product called Fusion Shield that was sold for a short time, before problems with out-gassing blew it out of the water. Did anyone ever come up with a way to make it work?

I purchased a 18" diameter piece, and a 9" diameter piece, before the problems became known. The first shipment, the 18" piece arrived broken, and the manufacturer replaced it. I only used the replacement once, after it blew a 4" bubble under a 16" x 3/4" bowl blank, but I've periodically thought about trying to make it "usable", and I wonder if anyone else has considered doing so, or if anyone else kept the material....or just threw it away.

I started thinking about this recently, because I had a request for a sample of a small oval piece (9" x 5"), with a logo deep-carved into the glass (1/2" Starphire), and the customer wanted the logo as clear as possible, rather than frosted as sandblasted. They also wanted the background and outer edge as clear as possible. I decided to try an experiment: After carving the glass, I took a piece of the Fusion Shield that was larger than the glass, cleaned and polished the surface, and then drilled several 1/32" diameter holes through the material in places that would allow any gases that might gather below the carved areas to vent. Since I was only firing to 1300*, I wasn't so worried about distortion of the glass as I would be if going to full-fuse, though I left the glass at top temp for enough time for the frost to clear out. Everything worked to perfection, with the underside almost imperfection-free, so now I'm considering trying to "fix" the diameters.

When I drilled the small holes in the broken piece, I found that it did not want to drill through the bottom of the material cleanly. No matter how carefully I tried, going extra slow nearing penetration, the material "popped" the last bit, even though it was fully supported by a piece of wood, leaving small-to-larger "craters". The material is thick enough (1") that I don't think this will compromise the strength, but I'd rather that didn't happen. Looking at the underside of the material, it was obviously cast, and there are a fair number of open bubbles over the surface. I don't know if that surface was heated in the production, creating more dense, harder/brittle layer, that might drill better if a carbide drill was used, but I'm considering taking that step. My idea, at this point, is to drill holes to completely cover the diameters with a grid, with the holes 1/2" on center, with the idea that any gases released from the material during a full-fuse would escape without creating a distortion in the glass above. I also have considered bringing the pieces to full-fuse temp, or above, and holding for a period (an hour? longer?) to see if the material would "complete" the off-gassing, though I would have expected the manufacturer to check to see if this might be a solution to the problem before he ceased marketing the product.

The Fusion Shield material, whatever its make-up, does not stick to glass after cooling, and does result in a very smooth finished surface, without the need for a release. I'd like to hear from anyone who tried to solve the out-gassing problem, and what their experience was.

Thanks!

Kevin, thanks for the link. I didn't remember that someone had tried a long, hot, firing to try to eliminate the out-gassing. Maybe I'll try doing that myself, now that the pieces have been sitting for 10 years. Maybe I'll get lucky! I wish I knew what, exactly, the stuff was, because even with the out-gassing I bet there could be some uses for it in certain situations....like damming, possibly. It sure leaves a nice smooth surface, with no mess. I've had some success firing glass on a bed of 100% aluminum hydroxide, and that can result in an almost blemish-free surface. But, dealing with that is a bit of an aggravation, unless you like ultra-dry skin for a while.

Mark Selleck wrote:
The Fusion Shield material, whatever its make-up, does not stick to glass after cooling, and does result in a very smooth finished surface, without the need for a release. I'd like to hear from anyone who tried to solve the out-gassing problem, and what their experience was.

Thanks!

Hi, Mark: I'm not familiar with the product, but there are a couple of clues in your post that got me thinkin'. The glass surface being really smooth after firing may indicate that the outer edges of the glass seal to the Fusion Shield (FS) before gases are vented; might some normal bubble-prevention techniques allow gasses to be vented from between the glass and FS e.g. bubble squeeze in heating program; chads at glass perimeter to support glass off of FS; breaks in base glass layer; and glass powder spread on FS to support glass until process temperatures are reached (I've heard this works and it is my favorite speculation as it can be used with solid base glass)? Might a hole drilled through the glass that will fill at process temps allow gas to vent? The hole may need to be 'V' shaped so it doesn't end up being a bubble maker itself and placement of the hole(s) might be guesses at best as well as the holes potentially leaving a 'scar.'

I drill and cut from both top and bottom or from both sides to avoid what I call 'break-outs' which sound like what you described in your discussion of actually drilling through the product; this could be a little difficult to do without the product being at least translucent.

I've been thinking about how to produce really smooth fusing surfaces not requiring a release and this thought process is helpful to me in that regard if not on the mark for you. Thanks for the thought-provoking post.

Mark,

Before the company took the product off the market, they had done some experimentation with ways to make it work. As I recall, one way was to drill lots of holes (as you've tried);the other was to scrub the product with the rough side of a Scotch-brite kitchen sponge. The theory was that roughing up the surface would help with the bubble problem. I never tried that suggestion, but the company told me that it worked for them. But they still decided to take the product off the market because if you had to scrub the shelf before each use it would be just as easy to kiln wash it.

If you try the scrubbing and it works, let us know. I still have one of the shelves around somewhere. It leaves a really smooth finish if the glass piece is small enough that the bubbles aren't a problem. (And it creates some spectacularly large bubbles on bigger pieces.)

One more thought -- if you do another firing, go slowly from 1100 to 1300 and hold for awhile around 1300 or so to see if that helps the gas escape.

Jerry, thanks for your input. As far as I could tell, and from what others said at the time this product was available, the product out-gassed continuously. There was a build-up of gas under the glass AFTER the glass melted and the glass sealed itself to the FS surface. I don't believe that using powder/frit under the glass would eliminate the problem, though it might minimize build-up until the center "sagged" to meet the FS surface, but once the center of the glass piece was soft enough to start sealing itself to the FS surface, any gas generated under it would try to rise through the glass, or lift it, and that area would expand as the rest of the glass made contact with the FS surface and reached full-fuse temperature. The 4" diameter bubble that was created under the piece I fused on the FS was about tall enough to put a billiard ball under it, and it began about 3" from the edge of the disc and extended inward toward the center. That's a lot of pressure build-up, considering the glass was 3/4" thick.

I don't believe that it would be worth the trouble to try drilling holes in the glass surface to vent the gas, considering the possible resulting imperfections. Drilling holes in the FS material, to allow venting through the bottom, makes more sense to me, and with the 1/32" diameter holes I don't believe there will be a noticeable pattern of imperfections left on the glass, especially if the resulting piece is later slumped to form a bowl. I wish I could drill from both sides, as I've done with clear float glass, but doing so with such a small drill, with the number of holes I will have to drill, would be a major pain (We're talking in the neighborhood of 1000 holes at 1/2" on center spacing. Maybe I'll try 1" instead, as a start. ). I will experiment with a small broken piece to see if I can come up with a better method than that I used for the first piece.

Brad, thanks for your response. I was wondering if you might have a piece of the material on a shelf somewhere.

I'm going to drill holes in the small disc I have first, and see how it performs. That's a lot fewer holes than will be needed for the large disc. If scrubbing it with a Scotch pad would work, that would be a positive, but you would lose the really smooth surface. I guess the resulting texture might still be pretty smooth, but if you have to scrub each time I don't know that the cost of the material would have been worth it. (Actually, I'm not sure why it would be necessary to scrub each time, if the glass isn't sticking to the FS?) The big attraction is the possibility of a very smooth finished surface, that does not require repeated application of a release, and the time/mess that entails. I'll let you know what my result is. Slowing down the ramp up I don't think will be of benefit, for the same reason I don't think using frit would be, but I may try that when I fire a glass piece just to see if the 10 years of aging may have changed the properties of the material.