Words of advice for Lexan? Making a Kammback

[turbovr41991]

Does anyone have any words of advice for working with Lexan? I am wanting to make a rounded kammback and thought transparent lexan might be a good choice. My plan is to make a complete mold for it out of wood. This way I can ensure it is vurturally perfect. Next, I would center the lexan in the desired spot, then with a heat gun, slowly let the lexan drop into place. I envision this creating the identical curvature of my mold making it virtually perfect for maximum efficiency. After it has formed and cooled, I would then carefully cut it to the needed size, add mounting hardware and brackets and possibly tint. What are everyone thoughts? Is using something transparent like lexan a pipe dream of overly complicated? Should I just abort and make with ABS plastic or another durable material. Thank in advance.

[GeekForLife]

Polycarbonate has a melting point of 155 deg.
I personally think that if you are going to build a mold go the extra step and put the mold in a inclosed box and bring the temperature up slowly with a space heater for a uniformed bend.

My only concern with a heat gun is that the results my come out wavy on a large sheet.

[botsapper]

Polycarbonate sheet guides;

A useful guide. http://www.theplasticshop.co.uk/plas...sing_guide.pdf

http://www.plasticsintl.com/document...on%20Guide.pdf

http://www.plexiglas.com/literature/pdf/94.pdf

[GeekForLife]

Awesome Reference material I like the second link best.

[kach22i]

One idea which I've thought of and maybe other's have actually done before I even had the idea is to place a third brake light inside of the transparent or semi-transparent enclosure or tail.

The goal of this would be to use the internal light refraction to make the entire rear glow. In affect the back of the car becomes a giant tail light.

This could add a little extra margin of safety which is needed because of the small surface area of the rear.

My old Porsche 911 has a small rear surface area, and so do motorcycles, and people seem to have a very hard time judging distances, be it to the back or even the side. They tend to want to drive you off the road and take over your lane, perhaps because you are not filling it out or something.

It goes beyond mere aggression, and is a spacial occupancy thing.

In addition, I think red cars have less of a problem with this tailgating and side swiping than let's say silver/gray cars.

Diminutive size can be partially compensated for with loud colors, think of some poisonous snakes and frogs for instance.

[radioranger]

good point on the driver aggression thing, people use their cars as threats all the time. personally i laugh when the cut right in front of me, gives me a better draft and i dont get angry about it anymore, Both my little ranger and silver Escort are prime targets so well aware of this effect, also if some soccer Mom is tailing me i pull over and it freaks them out , LOL as they say. course every light after i am right behind them coasting up as they wait for the green, Just part of the ecomodder lifestyle i guess,

[kach22i]

Found an example.

The Dolphin: Super Aerodynamic Homebuilt Electric Car



There are ways to try and reclaim and "your space", as with this wing.

Jeep Treo concept to debut at the Tokyo Motor Show


The Concept Car Thread - Page 3 - Team-BHP

[turbovr41991]

Originally Posted by kach22i

The Dolphin: Super Aerodynamic Homebuilt Electric Car

Wow. That is awesome. I would love to do that....

[blowncopcar]

I put lexan in the middle of my khaammback and then rounded it slightly by putting a piece of lexan up in the middle going from the back window to the khaammback, so it put pressure up on the middle of the main lexan in the khaammback ... And when the third brake light comes on it lights up... I need to take pictures.... One day

[Vekke]

Biggest problem is heat expansions which warps the glass easily. I have tried to solve that problem by heating the glass hotter +35 celsius all the time when its glued. So when temps are +20 celsius glass is smaller and it pulls itself straight.

https://www.facebook.com/photo.php?f...type=1&theater

Oh and I used angle grinder with 0.8mm blade to cut that 2mm thick sheet. It worked nicely.