I'm making some kustom parts for this Cadillac I am working on and my friend Jack will be doing the machining, my question is....... What type of plastic is good for that??? LEXAN? PLEXI? What else is out there?? There is a huge plastic company in NOHO, CA, BUT THEY ARE NOT MUCH HELP!!!!! Thank you!!!!
Man the lexan I have dealt with seems to be very workable, especially when taking your time working it. And pretty sure you can get it in many thickneses
The harder the better, you will have less scratching and gumming up during the machine work. I thik Lexan is youronly choice. You didn't say if the parts were to be clear or colored? does Lexan come in colors?
I used to machine plexiglas. It was no problem. Water is usually the best coolant to use. Don't have any experience with lexan. It's softer than plexi. It might want to try and gum up with heat. LOTS of coolant is always best.
Yes it does, when the wife was still working for GE Polymeres our cost on it was 400.00 for a 4x8 sheet of 3/16. I have machined some we used it for windows on the presses when I worked for the Star. Your have to take your time with it if you crowd it, it will melt.
What to use probably depends on what you're making. I've played around with lexan for the underwater robots, it machines ok. and this high school robotics team makes the whole damn thing out of Lexan
call superior plastics in gardena. they do all sorts of acrylic manufacturing and custom stuff. they've always been very helpful. www.superiorplasticfab.com 2124 West Rosecrans Avenue Gardena, CA 90249-2934 (310) 515-5111
Lexan and polycarbonate machine better than regular plexiglass. We machine it all the time on manual and CNC mills using 2-flute HSS or carbide endmills and water soluble coolant. If you are worried about edge damage, it can be sandwiched between pieces of aluminum which gives it some protection. This is almost a must-do with thinner stock. Bob
We machine a lot of polycarbonate and is very easy to work with. I think its cheaper than Lexan. Typically the machined surface or feature will turn a frosty white color so to restore the clear surface we apply a very thin coat of "Acrylic adhesive SC-125" ($20). Keep in mind this is an adhesive but it works really well. We use a glass syringe with a SSTL needle tip (22-24 gauge)to dispense the adhesive.
Polyester (often called mylar, DuPont name, all the same shit)- very soft, best long term ultra violet treated PETG- Medium softness, blend of polycarb and polyester. very easy to form, laser cut Polycarbonate (trade name lexan. Same stuff) harder, ok with UV but not great. some hardcoats available. no laser cutting, cnc router ok but edges get rough. Thicker the better Plexiglas (trade name Plexiglas) hardest, best for machining in thinner gauges as it is rigid, cnc router at least. worst for UV degradation I can get it cheap, but shipping would kill you.
Plexiglas will turn yellow over time, especially if it is exposed to the sun! Acrylic most likely won't.
Polycarbonate is really easy to work with. If making lenses, just polish after molding it, shines nice. .................................... Taildragger&fenderless
Guys, Plexiglas is Acrylic Lexan is Polycarbonate Mylar is Polyester And then there are blends for injection molding....
i work in the same building as an aircraft machine shop. i asked them and they said they machine lexan all the time both on the manual and cnc machines. i believe feature cam (the cnc program Haas uses) had Lexan as an option to machine. just keep it cool
Thanx sooooo much for all the amazing info! Just bought a few samples and we'll see what works best! I'm gonna pass all the info to my machinist , JackCreep on here! Thanx again! What I'm making is a secret..... I don't want someone to steal my idea before I am finished! Haha!
Do you absolutely have to machine your part? Could it be molded in the shape you require rather than machining it?
I did see a show where they made a clear clutch cover for a dirt bike. After the machining, it was a block, they went over it with a torch to get rid of the cloudy look, it melted it just a bit, and the clairity came right back.
You guys are just full of great info!!! Casting would be way too time consuming as i need quite few pieces!!!
After machining, if you want the "clear" back, you can quickly pass a torch over the machined area and the machining marks will "melt" back to the clear appearance!
if they're flat, its no sweat. if you want neato curvy shapes, a little heat and encouragement and you can make them that stuff do whatever you want... bubble tops, custom lenses, you name it.
Ian, Actually if you were to cast them you only have to create ONE then make a mold and cast as many as you like. Just a thought. Larry
I work in the sign business and cut plastic on my cnc machine everyday. Lexan gums up and breaks bits. Cast acrylic is the way to go. Plus lexan yellows over time.
If you flame polish the edge, be careful what you clean it with because you can cause the edge to crase.
We used a lot of acrylic sheet in the workshop at my previous school, admitedly small scale stuff, it machines well with routers, millers, small scale cnc machines and laser cutter,. Cut edges can be polished in several ways; Various grades of wet and dry paper usually 800,1000,1200 then a polish with brasso, solvol or something similar, even toothpaste works, A polishing mop with the finest grade of soap/compound (I can't remember the colour but one is specifically made for acrylic) don't apply too much pressure as the acrylic can melt, asd small parts can grab in the mops, usual safety rules apply here. Edges can be scaped using a woodworker's cabinet scraper or the edge of an old steel rule. (use u/s ones that have been damaged)
I can't thank you enough for all the help guys! Maybe I'll make a mold! I need 50 little pieces that will be pushed in the ends of 4 tube grills! That's what I'm up to! Just dont wanna make another tube grill ya know?!?!
Ian, and everyone else if you want 6 pieces of 3/4 clear lexan bar stock to make stuff out of @24 inches long check the add I just placed in the classifieds $5.00 Plus Postage. Red Hot HAMB Deal! Bob
The Jalopy Journal
