Making a more fragile body than Lexan?
 

That probably sounds stupid, but what I'm hoping to be able to accomplish is to easily and cheaply form a body that's more fragile than lexan. I'm interested in making some videos that sort of duplicate the awesome car chase scenes that I grew up with in the 80s, and to make them look as realistic as possible, I want to be able to use some car bodies that will crush a bit on impact.

My plan is to have a "hero" body for the detailed shots and a "stunt" body for the jumps & crashes. To create the stunt body, my plan is to start with a fresh lexan body, and use it as a mold. On the inside of the body I want to try applying a thin coat of silicone mold material, then back that with a couple thin layers of paper mache. My thought here is that the body should be just strong enough to hold its shape, but should collapse nicely on impact. The rubberized outer shell should prevent it from cracking, and should help it look more like real sheet metal damage.

Does anybody have any other ideas for how I could easily and cheaply make these body shells? Because I'm going to wind up trashing a fairly large quantity of these, it's got to be something that I can make quickly, easily, and cheaply.

Thanks!

Re: Making a more fragile body than Lexan?
 

You can try to see if you can do something with material like aluminum foil? It can crumple and be reshaped over and over again.

Re: Making a more fragile body than Lexan?
 

I thought about foil, but dismissed it because it's pretty much impossible to get it smooth enough for it to look realistic... but maybe the foil can be the backing behind the silicone instead of the paper mache? That seems like it could be a winner.

Re: Making a more fragile body than Lexan?
 

I’m sure if you find the right chemical it will weaken Lexan. That way you have all of the normal body selection to choose from. You could also make your own vacuum former to duplicate the bodies cheaply. Then if you vacuum form your own you could make the bodies out of thinner Lexan which would also decrease the strength.

Re: Making a more fragile body than Lexan?
 

Acetone will make lexan brittle.... doesn't take much.

Re: Making a more fragile body than Lexan?
 

Use to be a guy here, Metal Masher, formed bodies out of thin sheet metal. http://www.rccrawler.com/forum/1-9-s...yota-body.html

Here's another one: http://www.rccrawler.com/forum/2-2-s...eos-willy.html

Somewhere in the Non-Crawler section he built a couple demolition derby cars: http://www.rccrawler.com/forum/non-c...demo-cars.html

Search RC Demo Derby on YouTube, there's a bunch.

And then there's b-kons '61 Dodge D100, and he shows step by step how he forms the metal, and the finished product on YouTube: https://www.youtube.com/watch?v=NwSIgDKvMHk

https://www.youtube.com/watch?v=Cv3rV7Nll50

Re: Making a more fragile body than Lexan?
 

Good ideas, but both will be more expense/effort than I'm really willing to expend.

Thanks, but that's WAY more complicated than I want to deal with, especially for something that I specifically intend to destroy.

Re: Making a more fragile body than Lexan?
 

I think the really cheap chinese bodies are made of paper thin lexan.

Re: Making a more fragile body than Lexan?
 

Good point. And some are ABS which is even more brittle.

Re: Making a more fragile body than Lexan?
 

PETG vacuum forms at a lower heat than lexan and is cheap. Lexan paint makes it brittle, so your body will shatter if that is the desired response. Need to replicate a polycarbonate/lexan (material name and the brand name are the same stuff) body? DM me and I'll give you some pointers. Look for some .025 type "O" aluminum, preferably 3003. Soft enough to form easily and crashes will leave a mark, so to speak. Or, make one out of .025-.040 (use 3003 H14), then anneal it by heating it with a map torch then quenching it in cold water. Even .063 gets really soft. Weld/epoxy/JB Weld as necessary to be completed then paint.

Re: Making a more fragile body than Lexan?
 

This is probably of limited help to you but it reminds of my days in SC racing and the fact that you could get one body that had the quarter panels/hood etc held on with velcro so they'd fly off in a crash.

Re: Making a more fragile body than Lexan?
 

Initially I dismissed forming aluminum panels because I thought that the foil would be too thin/weak, but after seeing some of the process done with some thicker foil, I think it might be a viable option IF I can separate mold into an appropriate number of pieces to balance moldability with ease of construction. In the long run this might be the best solution because it will allow me to reuse the undamaged parts.

I'm still not convinced that this is the easiest solution, but I may give it a try. It will definitely be the solution that provides the most realistic results.

Re: Making a more fragile body than Lexan?
 

"thumbsup""thumbsup" It may not be easier, but it'll look the most realistic when getting damaged, and like Metal Masher, you can always bend them back out like a shadetree mechanic might do.

If you make a set of molds, or bucks, I think they're called, you can always make a fresh set when the damage becomes too extreme.

Re: Making a more fragile body than Lexan?
 

I'm sure it'll look better, but the time involved in making molds/bucks and forming & reforming all of these aluminum panels just for 10 seconds of crash footage hardly seems worth it. I'm still racking my brain over other options that could be more efficient.

In the near future I need to try experimenting with some foil to see it it's worth it.

Re: Making a more fragile body than Lexan?
 

Metal Masher is a member here who was doing this back in the day. He may or may not still be active but check his threads.

Re: Making a more fragile body than Lexan?
 

I have. His work is impressive, but I'm struggling with whether it's worth the large amount of effort for me.