One of the brutal ironies of bullet resistant glass in a retail setting is that monolithic acrylic can stop a .44 magnum bullet, but will be ruined by a googly-eyed reindeer sticker. No matter how many extra cartons of egg nog your holiday cheer sells, it’s going to be hard to absorb that $6,000 mistake.
RULES FOR BULLET RESISTANT GLASS SIGNAGE
Total Security Solutions vice president Jim Richards makes a point of coaching every customer in the proper care and feeding of bullet resistant glass, but he finds that this training frequently doesn’t make it past the managers. With the number of things that new hires and holiday help need to be taught about stock, sales procedures, registers, inventory, and so on, a warning about not putting stickers on the bullet resistant barriers is frequently lost in the shuffle.
The problem is that bullet resistant glass looks just like window glass (albeit much thicker), and retail workers are accustomed to temporarily taping up signs during the holiday sales season, then using glass cleaner to remove the residue when they peal down the sign a few days later. Tempered display window glass has an annealed, impermeable surface; it is very hard and essentially chemically inert. Acrylic, on the other hand, is a thermoplastic with a slightly porous surface that interacts very differently with chemical adhesives and cleaners.
It’s also not uncommon to use a razor blade to scrape tape or stickers from a plate glass display window. This is fine for glass, which is a remarkably hard (if brittle) material, but terrible for acrylic, which will certainly be scratched in the process. And, unlike glass or metal, scratches cannot be buffed out of bullet resistant glass.
This isn’t to say that adhesives or scratches cause structural damage to the acrylic–a sheet of bullet resistant glass stops a 9mm bullet just as well with banana stickers as without–but adhesives will scar the surface, and an apologetic workers’ attempts to clean up the mess can make it much, much uglier.
There are two ironclad rules when it comes to mounting temporary signs on bullet resistant glass:
1.) NEVER PUT ADHESIVES ON BULLET RESISTANT GLASS!
The adhesive backing on most stickers and tape eats away at the finish on monolithic acrylic. If something is taped up just briefly it might not seem to do any damage, but that doesn’t mean that it can be left up indefinitely. The worst culprit here is common scotch tape. According to Jim “That stuff’s impossible once it’s on there for even a couple days. After a couple days it starts to absorb into the material. Then, inevitably, some kid tries to scrape it off with a utility knife, and it’s over.” This brings us to rule #2:
2.) ONLY CLEAN BULLET RESISTANT GLASS WITH MILD SOAP AND WATER!
Acrylic is heated during fabrication, causing microscopic fissures to form in the material. These are invisible, and have no impact on the material’s structural integrity. But when acrylic is cleaned something like Windex, the ammonia in the cleaner attacks the edges of these fissures, causing optical imperfections that then refract light and make the acrylic appear to be filled with a hazy spider-web of rainbow cracks (called “crazing.”)
SIGN OPTIONS FOR BULLET RESISTANT GLASS
For temporary signage on bullet resistant glass, static stickers are terrific. These can be printed at most copy shops and have the advantage of being easily reused, year after year. For permanent signs, Jim notes that conventional vinyl decals–which any sign maker can produce–work just as well on bullet resistant glass as they do on plate glass.
