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Making Lexan Body Molds?


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#1 bossgrabber1970

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Posted 25 September 2010 - 03:07 AM

does anyone know of any books on how to make lexan body molds? i was looking on ebay for some parts to fix my 1:1 mercury cyclone and ran across a listing for a 1970 ford torino gt for sale. i was thumbing through the listing and was getting to the end of the description, the person who was selling it had taken some very good shots of the car at just about every angle with some very good details. i saved the pics and wanted to "attempt" to make a 1/10 scale body of the car. i never ventured into anything like this but i figured it's worth a shot. here are a few pics of what i would like to build if possible. any help would be greatly appreciated.




[attachment=10526:torino1.jpg]





[attachment=10527:torino2r.jpg]





[attachment=10528:torino14r.jpg]




[attachment=10529:torino24r.jpg]

Edited by bossgrabber1970, 25 September 2010 - 03:12 AM.


#2 BeetleLover

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Posted 25 September 2010 - 05:24 AM

It really can be a time consuming and expensive process and quality largely related to your model making experience. If you found a "Toy" car of the correct model at the right scale you could prepare it by backfilling holes, eliminating undercuts and modifying features that might be too complex to get in a vac form. When you vac form you exert tremendous pressure per square inch on your "buck" or mold. A toy car under vacuum would self destruct so you need to mold your original preferably in a silicon rubber and then cast out a solid resin buck to vac form over. You could model build your car buck from scratch preferably from solid wood or laminated sections. You might find yourself having to bog and fill sections to get the perfect surface or shape... Problem here is quite often the heat of vac forming shrinks such things as bog etc and the buck will become damaged after each attempt to get a clean bodyshell off the buck. Ideally you still need to invest in the molding and casting to get a solid buck with nothing extra that can delaminate or become damaged in the process... Done right and with time taken your efforts will be rewarded, rush it and try and take shortcuts you'll be really disappointed.

Best of luck if you pursue it, looks like a great car!

James

#3 DCLXVI

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Posted 25 September 2010 - 07:22 AM

I don't think it's neccecarily that expensive to make your own body, I'm quite sure it's time consuming though...

http://www.instructa...t-plastic-vacu/

#4 VagabondStarJXF

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Posted 25 September 2010 - 07:33 AM

It really can be a time consuming and expensive process and quality largely related to your model making experience.

Like the man said!

Strangely, back when I was at school we actually tried making body shells in our CDT class. They had a vacuum forming machine there and we had a 'challenge' of making RC cars with soda can wheels. Being the kind of kid I am I tried to put as much effort as I could into the buck I was making out of wood. The time I spent on it was immense and I ended up being told off by the teacher because he claimed it'd never mould. I always thought it was basic but what did I know compared to the teacher, right? So I moulded it and, looking back through my memories, it actually looked like a sorta squashed PT Cruiser. The plastic also came off the buck ok from what I can remember.

If you do make it out of wood be sure to sand everything smooth, especially if you have to screw several sheets together like I had to. I've heard that making it out of metal works a lot better but I wouldn't try that unless you've got some serious metalworking skills and the tools to get the job done.

Edit:

I don't think it's neccecarily that expensive to make your own body, I'm quite sure it's time consuming though...

http://www.instructa...t-plastic-vacu/

OMG. That's awesome. I think I'll have to reconsider my plan to not make my own body shells.
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#5 BeetleLover

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Posted 25 September 2010 - 08:26 AM

It looks easy enough, and certainly home made equipment seems straight forward and cheap enough to create but from my experience with commercial equipment sometimes even relatively modest bucks can be deceptively tricky. I still standby the need to mold and cast the buck to avoid a deteriorating former/buck especially if you intend to form a few shells. There's a bit of knack to it, getting plastic to correct temperature, speed at which you vacuum (I recommend a valve to adjust the draw as the plastic comes down) Any vertical sections or near vertical sections can cause folds etc on corners so be clever with extra fillets and think about cutting lines. It will also be likely that you'll need to drill holes in your buck in corners and tight spots to ensure the vacuum can still suck once the edges are drawn down. One thing that can catch people too is not having enough run off below the level of you vac piece which can result in sides that flair outwards still within the detail of your cutline/edge of piece.

I spent $200 - $250 US for silicon and resin to create accurate Wild One and Driver bucks. Not huge money but you've got to be committed if you want to do it right and take the time to get the buck right otherwise it can be a costly mistake. I also experimented with plaster and another similar casting stone (forgot the name, had less shrinkage qualities) you get good suction due to the porous nature but I wasn't happy with the surface, it had a light texture. I'd made Terra Scorcher wings but wasn't satisfied enough with the quality to offer them up for sale. Don't get me started on shrinkage and size changing a bit here and a bit there as well considering the thickness of your material scaling your piece up slightly, body mount holes can drift!

Get started on that project it will be a real learning process!

James

#6 bossgrabber1970

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Posted 25 September 2010 - 02:06 PM

thanks for the great info guys. it's going to be a little involved in actually making the body so a cast can be made but i have nothing but time to get the proportions right. as for the vacuum former, i have a very good friend that can build me one. i figure since some of the bodies i want are not being produced, why not build my own. i used to draw and build when i was younger and i figure why not get back into model building just at a bigger scale and detail. i can actually put my dormant autocad and mechanical drafting skills back to good use. it would be nice to see 1/10 scale version of some of my favorite muscle cars, the torino being one of them and a aussie falcon xb coupe among others. i think the torino would be tough due to all the curves and details but still buildable.



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