Lexan is ...

thinking in starting to make my own "car

It doesn't have to be much fancy so I

material an check it's price.

Electrics, from US but because I am from

unique material? Or I can find similar

Where can I find it, preferably in Portugal or

Lexan is GE's trade name for Polycarbonate Any company dealing in plastics should be able get it for you.

Lexan is a proprietary formulation of acrylic. It can be had with increased Ozone and UV protection but Plexiglas in similar in most features except impact resistance. R. Wink

thinking in starting to make my own "car

doesn't have to be much fancy so I

material an check it's price.

from US but because I am from

material? Or I can find similar

I find it, preferably in Portugal or

NO, it most definitely is not acrylic. Lexan is used for everything from bulletproof windows to blender jars. It is much stronger than any acrylic. It also behaves completely differently than acrylic when heated. My first job was feeding and caring for injection molding machines making small Lexan pads with a tiny stainless steel insert in them for dental braces. We used acrylic to clean out machines when going from one kind of plastic to another.

I also get the impression that the Lexan R/C car bodies the poster is talking about are blow-molded vice vac-formed. At least the ones I've seen.

Either way, seems like much more cost and equippment would be required than the "average" pocketbook might contain to form Lexan at home...true, or not?

Polycarbonate

am thinking in starting to make my own "car

machine. It doesn't have to be much fancy so I

Lexan material an check it's price.

Electrics, from US but because I am from

unique material? Or I can find similar

can I find it, preferably in Portugal or

It's a floor wax and a dessert topping.

Craig

in article snipped-for-privacy@earthlink.net, Craig at snipped-for-privacy@earthlink.net wrote on 6/17/04 7:53 AM:

Floor wax? I thought it was similar to Plexiglas and was used for greenhouse windows and the like because it is hard to break.

I don't know if the regular "plastic solvents" will work on it.

MB

That's where I got the idea they are blow molded - no little bumps...Lexan R/C car bodies are glass-smooth, and usually painted on the inside to preserve the glossy surface on the outside.

But the question remains - can you heat mold a polycarbonate? Most of the things made out of polycarb that I'm familiar with (aircraft canopies, bulletproof glass, aircrew visors) are laminates. Don't really know how they do it.

Lexan is a thermoplastic- it softens with heat. A thin film of lexan will blow mold or vacuform, but it probably acts a lot different than thermoforming styrene so you might need more suction, for example. It becomes a viscous fluid at about 400 or so degrees (if I remember right, been about 25 years now). BTW the opposite of a thermoplastic is a thermoset- they harden with heat, like the stuff those turquoise boomerang-shaped 1950's ashtrays are made of.

Yes you can vac or blow mold polycarbonates, they're just fussy to handle. Polycarb is all extruded sheet to start, stuff like Polycast II for jet fighter windscreens then goes through post extrusion processing to make it much denser than normal, either way the windscreens and canopies are blow molded. Not sure if they're laminated before or after molding.

Thanx - what I know is that the fighter windscreens and canopies that I have seen scratched or gouged appear to have a "weaved" substrate through them...even some pilot's visors I've seen are like that. I expect that these are layed up and fused somehow under heat/pressure to form the full-up transparency, and that the "weave" in the composite structure is where much of the strength comes from. I have no idea what the "weave" is, but I have seen broken ones appear splintered like a carbon fiber composite does when shattered. Would be interesting to see the process for a jet canopy.

Thanx - good info.

in article wAHAc.51290$2i5.31844@attbi_s52, Rufus at snipped-for-privacy@mchsi.com wrote on 6/18/04 2:42 PM:

The first use I heard of for Lexan was for Caboose windows. When I was a kid?and I know that was a while ago?we used to wait to wave and the engineer and then the brakemen in the caboose. Sometimes the brakeman, if he was local, might even throw a piece of hard candy or two. And then for some "reason" kids began throwing rocks at the caboose and breaking out the windows, hence the need for Lexan. Nowadays the cabooses are going away or have been deleted. It's a different time.

MB

It's not a weave, that's a diffraction pattern. We used the same stuff in biomedical detectors and if you heat then bend a strip it gets a weird diffraction pattern in some light and it fractures funny when it does go..........not like "normal" polycarbonates at all. Go google Polycast II.

I'm not sure regular Acryllic or Nylon would suit the needs of the original poster. For model car bodies the Acryllic would be too brittle to survive even minor impacts and Nylon would be difficult to paint. Ordinary Styrene would be better than either of these. Although its not really strong its cheap. So a number of replacement bodies could be easily made. Incidently there are certain paints that affect the properties of Polycarbonate. I seem to remember concerns about people re-painting Polycarb Motorcycle helmets with Lacquer based paints. It makes the plastic brittle.

Lacquers, alcohols, isocyanates and a few other chemicals affect polycarbonates. To greater or lesser degrees depending on which chemical, it's dilution and exposure time they will craze the surface.

Yes - that's the impression I get from scratching one (don't ask...) and from seeing them broken from birdstrikes. I know they are a laminate of some sort, but not sure of what...maybe the "weave" I've seen is the polycarbonate substrate and the matix is actually acrylic. Guessing...