I few months ago I helped to move the storage of a local theater, including costumes, props etc. In the process they threw away a lot of stuff, including a few sheets of some kind of plexi. I asked if I can take them and they agreed. They are of the following dimension: 2 x 150cm x 70cm x 1.5cm 2 x some weird triangular shape, about 170cm long 1.5cm thick 1x 1.80cm x 70cm x 1cm They are scratched pretty badly as they were used for some kind of glowing modern art hing, but the actors climbed around on them or so I was told, but I figured I could do something with them. Such large and heavy sheets must be pretty expensive if you buy them new. But then you wouldn't build a transparent plexi case out of sheets that are 1.5cm thick. To cut a long story short, my brother needs a new case. Nothing fancy but he wants it silent. A case made out of such material would be pretty quiet I guess, it's really heavy. No way you'd be able to hear a HDD humming inside. The plan is to cut some sheets and glue them together. However I'm not sure what glue to use. The sheets are really strong, and for the abuse they took they look great. I mean they are scratched, but no deep scratches as far as I can see, and no cracks. So they might be Lexan as well. Or they might not be, I've no idea. How can I find out what kind of plexi they are? I am looking for a strong bond, airtight preferred to reduce the dust intake. There's no need for a clear or fancy bond, I am going to sand down the outside and paint it if necessary.
I'm not sure about the glue, however the scratches can be fixed. Depending on how deep the scratches are, put a coarse sandpaper (maybe even as much as 40 grit!) on random orbit sander. It's pretty important that it's a random orbit sander, or you will never achieve 100% correction. Move the sander around constantly, never concentrate in one area. Although the paper only heats a little (~+15 degrees C if you're constantly moving), it's enough to slightly melt the surface and it goes cloudy. Take breaks in the sanding if you're unsure, err on the side of caution. Once you've corrected the scratches, then work through finer grades of paper (jump 200 grit at a time) until you're onto ~1500grit. Then comes the killer bit... polishing. This will make the perspex come alive! You need a "mop" which is just a wool head for your random orbit sander and some polish that says it's suitable for perspex / acrylic. It goes a kind of mirror clear way, it looks very striking, also it's a rare finish (noone does it) so it will really stand out.
Don't go any lower than 240 grit on a surface cleanup job! You will spend the rest of your life sanding out the scratches rough grits make. To determine if it's polycarb: Take a razor blade to one of the edges. If you can shave off a sliver of the plastic like wood, you have a polycarbonate. Glue- http://www.delviesplastics.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=DPI&Category_Code=Acrylic_Cement Video instructions at TapPlastics -I don't know how good your spoken English is, though. Hope This helps.
Thanks for your replies. I am not going to bother with cleaning up the surface. I'm gonna sand the sides with 240 grid paper to get a milky finish and be done with it. I'm terrible at writing in english, but spoken English and understanding in general is fine.
