How to Build Your Own Prototype Car Body..really!

[Ace-Garageguy]

This is pretty cool. I've been using an almost identical technique for more than 40 years to make prototype aftermarket car and aircraft parts...but I don't work quite this fast. 

PS. The same system also works for model parts.  

 

[jeffs396]

KEWL! 

[cobraman]

That was interesting.

[Spex84]

Holy moly, that's a lot of effort. Very interesting to see someone doing this without a styling bridge, fancy clay, etc. Just regular tools in a regular garage. And LOTS of patience.

Reminds me a little of the russian custom cars built with spray foam applied directly to the car, carved/sanded, and fiberglassed on top...

[Ace-Garageguy]

Holy moly, that's a lot of effort. Very interesting to see someone doing this without a styling bridge, fancy clay, etc. Just regular tools in a regular garage. And LOTS of patience.

Reminds me a little of the russian custom cars built with spray foam applied directly to the car, carved/sanded, and fiberglassed on top...

Just a reminder that it IS possible to turn out world-class results with pretty common tools...and as you say, a lot of patience.

Speaking of foam...my approach is often to start with 2'x2"X8' planks of urethane foam cut on a table saw into flexible strips, and to apply them to an armature; in this case, the backbone and ribs were made of common house-insulation boards, the whole thing assembled with hot-glue. The "styling bridge" was a set of carefully built interlocking tables with cabinet-grade plywood tops, and a sliding adjustable pointer (up / down, in / out)  that could be aligned with dimensioned tapes on the surface of the tables.

               

The foam is built up and sculpted to within about a quarter-inch of the final surface and then fiberglassed. That creates a rigid shell, just as in the video above, that can be final-finished with bondo. Molds are made at that point, and the laboriously constructed "plug" is broken up and thrown away...or in the case of the little vehicle just above, stored behind my home until I can get back to finishing it.   

 

Edited September 1, 2016 by Ace-Garageguy

[bobthehobbyguy]

Very interesting video.

[Spex84]

Speaking of foam...my approach is often to start with 2'x2"X8' planks of urethane foam cut on a table saw into flexible strips

 

Very cool, and that's probably how I'd want to approach it too. I'm trying to find some good foam right now for a model car interior, with the idea of applying some kind of filler on top (maybe Polyfill) and sanding it smooth.

About 10 years ago I knew a guy who was helping a university Formula SAE race team build their car...designed it in CAD, laminated sheets of foam into a block, CNC rough-milled it into shape, and discovered that the thin glue seams made hand-shaping the form very difficult, as the seams would always stand proud. They were hoping to lay up carbon fiber over the foam form. Never did find out if it worked in the end.

[Psychographic]

Very cool, and that's probably how I'd want to approach it too. I'm trying to find some good foam right now for a model car interior, with the idea of applying some kind of filler on top (maybe Polyfill) and sanding it smooth.

About 10 years ago I knew a guy who was helping a university Formula SAE race team build their car...designed it in CAD, laminated sheets of foam into a block, CNC rough-milled it into shape, and discovered that the thin glue seams made hand-shaping the form very difficult, as the seams would always stand proud. They were hoping to lay up carbon fiber over the foam form. Never did find out if it worked in the end.

Try using floral foam and after it's shaped give a coat or two of epoxy or fiberglass resin. The foam shapes very easy and is impervious to epoxy and resin.

[plastic-mechanic]

http://balsafoam.com/

[Snake45]

Try using floral foam and after it's shaped give a coat or two of epoxy or fiberglass resin. The foam shapes very easy and is impervious to epoxy and resin.

I've been planning to try that for some time. I need to make an ACCURATE gun nose for the Revellogram 1/48 A-26 Invader and I think this is probably the easiest way to do it.

[Ace-Garageguy]

I've been planning to try that for some time. I need to make an ACCURATE gun nose for the Revellogram 1/48 A-26 Invader and I think this is probably the easiest way to do it.

I make a lot of parts this way. One thing to remember is that though "floral foam" (expanded styrene) is impervious to epoxy, it will dissolve in plastic cement or polyester resin. I generally prefer to use urethane foam (I have a lot of scrap usually from 1:1 projects). Here's some corners for a rolled rear pan on a '32 Ford.

Snake...I'll be glad to send you some pieces of this foam, as well as a little cabosil (to thicken the epoxy into a paste) and some very fine f'glass cloth too...if you want to do your A-26 nose.

 

 

Edited September 2, 2016 by Ace-Garageguy

[Ace-Garageguy]

http://balsafoam.com/

Thanks. That's actually very helpful. Good stuff there.  

[Spex84]

Hey, great links guys. Thanks!

I have some floral foam but was hoping for something a little less likely to crumble into toxic dust while I work with it. Maybe mine is just too old.

[Impalow]

Very cool and brings back lots of old memories for me...  I produced several vehicle models like this in school.. Eventually we got into clay and CNC carving out of a bondo board type material.  But all of my first models were foam carved.

Bill your 3 wheeled example reminds me a lot of my old thesis model, sadly its become a shelf ornament... lots of work on that bad boy.   This was sculpted in clay, then molds pulled off of it, then fiberglass halves made from the molds then joined together.  All made from raw materials...

[Ace-Garageguy]

Very cool, and that's probably how I'd want to approach it too. I'm trying to find some good foam right now for a model car interior, with the idea of applying some kind of filler on top (maybe Polyfill) and sanding it smooth.

About 10 years ago I knew a guy who was helping a university Formula SAE race team build their car...designed it in CAD, laminated sheets of foam into a block, CNC rough-milled it into shape, and discovered that the thin glue seams made hand-shaping the form very difficult, as the seams would always stand proud. They were hoping to lay up carbon fiber over the foam form. Never did find out if it worked in the end.

I'll send you enough urethane foam scrap pieces to easily do an interior if you want. The stuff comes in different densities for different applications. The lightest would probably be what you need. It shapes MUCH better than floral foam. The urethane stuff IS toxic-dusty though. You need to wear a respirator if you use it.

Far as the glue-seams go on the 1"1 projects...yes, that IS an issue. After you've done this kind of stuff for a while, you design ahead several steps so the seams aren't where material will be shaped. Interesting your guys discovered the problem. 

[Ace-Garageguy]

Very cool and brings back lots of old memories for me...  I produced several vehicle models like this in school.. Eventually we got into clay and CNC carving out of a bondo board type material.  But all of my first models were foam carved.

Bill your 3 wheeled example reminds me a lot of my old thesis model, sadly its become a shelf ornament... lots of work on that bad boy.   This was sculpted in clay, then molds pulled off of it, then fiberglass halves made from the molds then joined together.  All made from raw materials...

WOW! THAT is gorgeous. Man, man, damm. 

My 3-wheeler model is 1/10 scale with provisions for mounting in a wind tunnel. I built it like an old balsa model...balsa bulkheads with stringers between...then covered in f'glass and bondo. It was easy to go from the 1:10  drawings up to full scale, and the real one is built much the same way.

I've built a few clays over the years too. This was a study for a gen-1 MR2 body kit.

Edited September 2, 2016 by Ace-Garageguy

[Psychographic]

 

 

One thing to remember is that though "floral foam" (expanded styrene) is impervious to epoxy, it will dissolve in plastic cement or polyester resin.

 

 

 

I wonder if the term floral foam can be more than one type of foam depending on where you get it. I know I used what was called floral foam to repair a hole in a fiberglass tail "tank" on a vintage quarter midget last year. The repair used polyester resin and the foam was not effected by it.

Edited September 3, 2016 by Psychographic

[Ace-Garageguy]

I wonder if the term floral foam can be more than one type of foam depending on where you get it. I know I used what was called floral foam to repair a hole in a fiberglass tail "tank" on a vintage quarter midget last year. The repair used polyester resin and the foam was not effected by it.

I really don't know about every form of foam labeled "floral" on the planet. What I DO know is that all of it I've encountered to date is styrene, and melts in gasoline, acetone or polyester resin...which is why I have little use for it these days. Some of it is more solvent-resistant than others, and you might be able to get away with using it for a Q&D form under polyester if you get lucky, and don't use excessive resin. 

Another thought...if you actually repaired a fuel tank with polyester resin, it will probably fail. Most polyesters will NOT resist fuel indefinitely (Vipel F-764 is one exception I know of). I see tanks "fixed" with polyester quite frequently. They always come in leaking.

What WILL work permanently is a high-performance epoxy like E-Z Poxy 87 or MGS 285 with 285 or 287 hardener. They MUST be mixed on a gram-scale to an accuracy of about .5%, and post-cured...but they WILL do the job for gasoline-based fuels.

It is also my current understanding that AOC Vipel F-764, MGS L160 with 163 hardener, and R&G Epoxy-C are ethanol resistant as well, but I have no personal experience with these in ethanol applications. 

Styrene foam is frequently used as form material for specialized epoxy-based parts (including fuel tanks) specifically because it WILL dissolve in several common solvents. The extremely light carbon-fiber wing spars for the Gossamer Albatross were made over styrene-foam forms that were dissolved out with acetone at the end of the process.

                                             

 

Edited September 3, 2016 by Ace-Garageguy

[Mooneyzs]

Bill... Thank you for sharing that. WOW is that ever so Impressive. I totally enjoyed watching that video. What a creative way to do things. I can totally see using that method or a variation of it in our hobby. 

[DrKerry]

Kool stuff and great info guys!!!!!! Never would of thought to use foam on projects.

[Spex84]

This thread is rad!

Eric, that model is really something. When I was in high school I was obsessed with car design,my favorites were car-design and development stories from the 50s and and 60s; I'd admire the old chalk and marker drawings (and try to emulate them), and I'd drool over modern design studies built by students of Art Center and CCS in Detroit.  That dream never really panned out.

I did end up in an Industrial Design program where I built some models out of blue foam and MDF with polyfilla and bondo to smooth things out. Worked pretty well, actually, as long as there was a neutral barrier between any lacquer-based products and the foam. Breathing the MDF dust probably took years off my life, haha.

 

Ace, I'll experiment a bit more with the foam I have access to, and if it doesn't work I might take you up on that offer!

[Psychographic]

 

Another thought...if you actually repaired a fuel tank with polyester resin, it will probably fail. Most polyesters will NOT resist fuel indefinitely (Vipel F-764 is one exception I know of). I see tanks "fixed" with polyester quite frequently. They always come in leaking.

 

A tail  tank on a quarter midget is fake, hence the quotes around the word tank in my post.

 

                                 

 

 

 

 

Edited September 3, 2016 by Psychographic

[Ace-Garageguy]

A tail  tank on a quarter midget is fake, hence the quotes around the word tank in my post.

 Gotcha. I should have realized that. Anyway, if you ever DO have need of resins that will last immersed in fuel, those I listed will.  

[Psychographic]

 Gotcha. I should have realized that. Anyway, if you ever DO have need of resins that will last immersed in fuel, those I listed will.  

Thanks, I'll keep that in mind. Do those epoxies work on metal? The only gas tanks I mess with are bike tanks.

[Ace-Garageguy]

...Do those epoxies work on metal? The only gas tanks I mess with are bike tanks.

The MGS 285 works well on properly prepared steel, but all repairs, even something like a pinhole, have to be backed up with very fine fiberglass cloth...not mat. I did a steel bike tank a couple years back that had been "customized" and the welds had a lot of pinholes. Bondo had been put over all of it with the usual results. Stripped, prepped and repaired, it's still holding just fine.

Nothing readily available sticks very well to aluminum tanks, but there IS some aviation goo (Pro-Seal PPG  P/S 890)) that will do the job. It will also seal fiberglass and steel tanks.

Speaking of which, I have a fiberglass Norton tank I'll probably never use. I've been thinking about making molds and producing a few. You know many Norton guys?

Kinda like this...