what if you built a frame, such as those P. Jensen does for his wood boards, then glass it? too heavy? won't work??
I imagine that'd work just fine, it certainly glues well enough. Haven't played with lexan a whole lot, though a buddy of mine runs a lexan/plexiglass fabricating outfit and filled me in on a few details. He mentioned that it can be bent/formed using a heat source and a form to make quite interesting shapes. At the time, I was more interested in machinable fin blanks, so I didn't really pursue it. As to the issue of how 'green' lexan/polycarbonates are.... apparently GE Plastics and Bayer Corporation of Germany are starting polycarbonate recycling programs for polycarbonate/metal/inks/dyes CDs and such - apparently there's quite a lot of those getting chucked. interesting stuff.
I worked with polycarbonates for over 20 years. The highest quality materials, properly used, are nearly impossible to break, shear or crack. I`ve seen sheets endure amazing amounts of extended outdoor abuse, both environmental and by humans! Visitors often asked me just how tough different "high impact" plastics really were... so I`d take a few assorted pieces, place them on the cement floor and then repeatedly smash them with a hammer. Among the few to survive, was polycarbonate. But, especially on larger sheets, polycarbonate's best qualities can be compromised by scribing the surface, exposure to certain solvents, glues and paints, introducing undue long-term tension, or through improper thermal forming techniques. BTW, I`ve made some sweet battens from long, 3/16" thick polycarbonate strips/scraps.
Hey, Dale , a question or two: First -polycarbonates and adhesives. As the stuff breaks down in some organic solvents ( acetone would probably do a number on it, or similar, but the only polycarbonate I have here to test is my glasses and I ain't doing it to them ) I'm thinking that epoxies and such, which don't tend to have a lot of such solvents in 'em, would probably be the way to go. Polyester resins, though, might be kind of a problem. What's your experience with 'em? Second - I've noticed that it's a real good idea to round corners and such when working with plexiglass and the like, so you don't get sharp corners which in turn lead to cracks. In something that gets flexed as much as a batten, I'd imagine this is exacerbated. Have you found similar problems/solutions? Thanks doc................
doc... I worked in the sign industry for over 30 years. I still keep sheets of Lexan in my shop for various projects. In comparison to other sheet plastics, polycarbonates were the toughest overall. Interestingly, one of the most severe long-term tests was vandalism! The criminal mind is endlessly creative. Reading through polycarbonate spec sheets tells the story of exposure to various solvents. Each brand has it`s own recommended (some proprietary) glues and thinners, paints, solvents, methods of application. I`ve found that acetone, lacquer thinner, tolulene, MEK, etc. all seem to attack the material, often quickly "crazing" and discoloring the surface. A quick wipe with solvent prior to bonding will often cause no harm to a sanded polycarbonate finish, but can permanently dull/smear a high gloss finish. I`ve never noticed any damage from mild solvents like mineral spirits and gum turpentine. I`ve sanded and successfully adhered polycarbonate to other materials with industrial grade contact cement, silicone, super glues, tolulene-based caulkings and various epoxies. But if used in an active, flexible application, polyester and epoxy resins never seemed to maintain 100% attachment to the sanded plastic for long term. There are also problems associated with bonding dissimilar materials which expand and contract (changes in temperature) at different rates. You`re right, doc... always a good idea to smoothly sand all edges... moreso with acrylic (plexiglass) than polycarbonate. Small cuts and nicks along an edge are an invitation to much bigger problems. The more flex/tension, the more critical a smooth, even finish on edges.
Thanks, Dale, that pretty much confirmed what I thought. I was, for a couple of moments, thinking about some as stiffeners but there seem to be lots of easier ways to go about it, lighter and more compatible. Likewise ( in real life, as it were) for boat windows; while it's nice to have something I can cut down on-site more than glass plate ( and not so prone to cracking when you take a belt sander to the edge of it) it's still kinda pricy and prone to scratching. Be nice to use it to fabricate some retro fins for obsolete boxes though.... http://www.swaylocks.com/resources/FAQS/