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Learning how to build Lotus Seven replicas...together!
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PostPosted: Fri Nov 08, 2013 8:09 pm 
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...and this being my first post, I'm not sure if it's been mentioned before.

As far as body work goes, there's a program called pepakura that takes 3-D files and unfolds them so that they can be printed onto paper. The reason this is good for us will be a little more clear if any of you have seen the website http://www.405th.com/forum.php


The basic idea is that you take the file, print it onto card stock; cut, fold and glue together the pieces and fiberglass in/over it and sand and paint your newly made fiberglass body panels. The website I mentioned has forums for people that make fiberglass movie/video game armors (think Iron Man, Halo and Mass Effect). You would have the option of making the 3-D images yourself or unfolding a finished file from a car already in production (or not in production) that you or one of your more computer savvy friends pulled from a video game. Say something like forza or gran turismo.

Has anyone tried this? Is anyone willing to put in the work? Am I plum crazy for suggesting it?

I would love to hear your thoughts.


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PostPosted: Fri Nov 08, 2013 9:49 pm 
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If you are a competant user of 3-D design software (say Rhyno to pick something really capable) then this would offer a neat way to generate an armature that was close enough to the final shape to take just a skim coat of fairing compound for a plug, BUT .... It is designed for paper folding, so you would need to fold up corrigated fibreboard (aka 'cardboard') as you suggest or create flexible joints (folds) in 1/8 plywood (or maybe make the armature out of light gauge sheet metal?), and then would need a friendly octipus to help asssemble the thing. Nonetheless, it is an intreaguing (sp?) approach.

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Isuzu Pickup/SR20DE, +401 COLD frame
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PostPosted: Sat Nov 09, 2013 8:40 am 
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I've glassed directly over card stock/kraft paper for moldless construction but glassing over foam allows for compound curves to be sanded into the part without polyester filler, which is heavy.

Also, large sheets of card stock would need support in the middle during the glassing process to be rigid enough to hold the shape. Interlocking strips of card stock behind the panel 90 degrees to the surface (similar to the support behind plastic car bumpers) would provide support, but it is more work. A foam core is much stiffer and lighter than card stock (which has a considerable amount of clay binder), as well as less senstive to water if it were to reach the core.

For strength and to prevent cracking later on, fiberglass needs to lay across the corners, so they should all have enough radius to allow the glass to stay down during curing unless vacuum bagging.

Smaller shapes without compound curves are much quicker and easier to make with sheet metal and welding or rivets.

However, heavy (.030" if memory serves) card stock is ideal for creating custom shapes for interior panels to be covered in vinyl. Dampen a few sheets, bend to shape and over lap them, let dry, sand a little, then glue on vinyl using a high quality yellow glue and screw or clip it on.


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PostPosted: Mon Nov 11, 2013 3:18 pm 
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The basic idea is the same as the book's in carving out foam and laying the fiberglass on top, then making a reverse for a mold. You have a basic shape in foam, as the support, then you lay the cut/folded/glued card stock over that. Resin over it, glass cloth/mat under, then body filler to smooth the surface. You use that as the first step in mold making. I'm sure you COULD try to use that as the actual piece, but with the paper and filler on the surface, the thing would be heavier than hell. Compound curves are pretty simple too. I know this because I've made one of the video game helmets from it myself.

To address the idea of using cardboard or sheet metal, there's no need to when you have different weights of card stock. The multitude of compound curves in the average panel, interior or exterior, would mean that there's not much chance of your polygons getting too much larger than your paper, for anyone worried about putting together multiple pieces.

I didn't mean to imply that this would solve the world of locost problems, just that it's another way to cheaply make body panels for the people who would rather put in time than money.


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