Glass sticks to almost anything when it’s hot and practically nothing when it’s cold, which is why I love it as a work surface. That’s also why it’s such a pain when you want to attach glass TO something. Once I tried attaching a hanger to glass with GE Silicone II.
Let’s just say that I’m very, very glad that pate de verre bounces.
My favorite pate de verre hangers are small acrylic French cleats (right) –they don’t make a shadow on the translucent glass, and they push the work out far enough from the wall that light can get in through the back. I bought the originals from my friend Barbara Muth; since then I’ve had my own cut at the local TAP Plastics.*
I first tried gluing them on with silicone; I will NEVER use it again (at least on glass hangers). VHB tape didn’t work much better (although the massive roll I got free from my metals guy was probably outdated). Most of the regular glass glues I’ve used aren’t fond of acrylic.
The adhesives website ThistoThat recommended Loctite Impruv 349. Took five phone calls and a very long drive to find it (you now can buy it on Amazon), but it does indeed provide a permanent bond between acrylic and glass.
Unfortunately, they’re not kidding when they say permanent. Just try UNgluing the stuff if you make a mistake. Which I did.
Backstory: Loctite recommended a $1,500 UV light to cure the Impruv. EEEEEK. My glassist friends scoffed and advised buying a UV bulb from from Home Depot for maybe $6. No contest there; I headed for Home Depot, found a nice swirly blacklight bulb and screwed it into a desk lamp. Then I turned it, full glare, onto cleat+glass.
18 hours later I tested the bond. That cleat slipped off the glass as easily as if I’d stuck it on with vaseline. Frustrated, I set the glass, slippery cleat and all, outside and went back in to drown my sorrows in lemonade.
5 minutes in the drizzly Oregon no-sun cured that adhesive beautifully, making a strock, rock-hard join. It was just too bad that the cleat had slipped down and was crooked, facing the wrong direction.
As promised, the Loctite 349 bond was pretty daggone permanent, and not even Loctite held out much hope for getting it off mechanically.
Someone suggested placing the sculpture in the oven, heating it to 500F and whacking it a couple of times to see if the cleat loosened. The glass, he said, probably wouldn’t break.
While browsing the HIS Glassworks website, I found Attack, an epoxy solvent, that promised to dissolve epoxies and cured polyester resins, ordered an 8-ounce can.
The instructions (which by the way caution you up one side and down the other that this stuff is NOT human-friendly) said to fill a container with Attack and immerse the piece, naughty glue joint and all. You then sealed the container and let it sit overnight. In the morning, you’d peel the pieces apart.
This was a largish sculpture; I didn’t have enough Attack, or an Attack-safe container big enough, to immerse the whole sculpture. And on the outside chance that this stuff could mess up pate de verre, I wanted it to confine it to the back area around the cleat.
I made a well of thick clay around the cleat and dumped in the Attack. It didn’t seem to do much, and the clay was holding it, so I covered the clay with a scrap sheet of clear acrylic to hold in the Attack.
In retrospect, that was pretty dumb thing to do.
In the morning, the Attack had dissolved about a quarter-inch of the cleat all around, turning it into a gummy, smelly goo. And it had turned my acrylic lid into a jello-like substance.
Unfortunately, the cleat was attached as permanently as ever. That spoke well for the original bond, but wasn’t getting me very far.
I scraped out the goo and dumped more Attack into the reservoir, and slowly developed a routine. Every 8-12 hours I’d check the mess, scrape out the old oozy acrylic, pour in new, and seal it up. The Attack was attacking the OUTside of the cleat, never actually getting to the joint itself.
After four days, it had dissolved all but maybe a half-inch square of the original 2x3x.5 inch cleat. I applied gentle but determined elbow grease and finally scraped off that little bit. The residue solidified into something like rubber cement once the solvent evaporated, making it easy to roll off the glass.
I scrubbed the glass with soap and water, then denatured alcohol, then acetone (which hopefully got rid of any residual Attack). Then I reattached the cleat in the right place with fresh Impruv, cured it, and delivered it (barely on time) to the gallery.
(BTW, I used a Feit UV bulb to cure the new Loctite. It works like a charm in a plain old desklamp for $10. Thanks, Gary.)
So, does Attack work? Yup. Eventually. If you’re patient, have four or five days and are willing to do a LOT of scraping and repouring.
At a single bottle per joint it’s a pretty expensive glue remover, but it did get a fully cured UV-adhesived chunk off my glass. The alternative–casting a new glass sculpture–would have cost a lot more in dollars and time.
I’m not sure how Attack would work in a glass-to-glass bond. In my case, it clearly attacked the cleat, not the joint, and worked from the outside in. I saw little or no capillary action pulling the remover into the glue joint. I suspect it would take quite awhile (although much less Attack) to do the job.
Ah well. At least I learned a lesson: “Think first, glue later.”
*Word of caution: If you have your local plastics supply store make a supply of these acrylic cleats, EMPHASIZE that the 45-degree angle on one edge must be perfectly straight and parallel to the cleat. My first batch was cut any which way, and absolutely useless.