Fiberglass bodies

[pappabear1973]

Hello. I was wondering if anyone has made fiberglass bodies for their models? If so, I would be interested in learning the process that you use. Thank U for any information.

[Casey]

Check out the Big Boyz section, Jody, as the 1/8 Barracuda was to be made (is still going to be made?) out of fiberglass, and I have seen a few other in that section, too. Might've been the 1/8 '41 Willys I'm thinking of, though.

[dpride]

Do you mean from scratch or copy an existing body?

[Ace-Garageguy]

I've made a lot of glass body panels for models, and a lot more for 1:1 cars and aircraft. The techniques are similar for all of it, up to and including full bodies.

Question: Are you meaning "from scratch" original work, or copying existing parts?

Either way, I have all the information you need.

Mold in progress:

Mold removed from master:

Trimmed mold, un-trimmed replica part, and master:

Original design 1/10 scale clay master in progress:

Original re-body design for client, full scale master in progress:

My avatar is also an original-design 1/10 sctatchbuilt fiberglass model, currently being developed as a 1:1 showcar.

Note: All images are my own, taken from internet sites.

Edited December 16, 2013 by Ace-Garageguy

[Eshaver]

Very spiffy !!!!!!!!!!!!!!!!

[Len Woodruff]

Very kool. I need to learn this technique.

[Lunajammer]

That, Bill, is but one of numerous reasons why I consider every technical element you bring to this forum to be valid. You know of what you speak.

[pappabear1973]

I mean creating a body, from scratch. However I understand that probably includes making a master or a buck. Is am looking at doing a 1/8 scale c cab of my own design and think it might be easier to do it that way since the body will bee over eight inches long. Thanks

[Kennyboy]

Bill, What do you use as a mold release?

[DrKerry]

Bill, What do you use as a mold release?

Crisco????? Sorry had to chime in.......LMBO

[Ace-Garageguy]

Bill, What do you use as a mold release?

Poly vinyl alcohol (PVA) http://store.hamiltonmarine.com/browse.cfm/poly-vinyl-alcohol-gl-pva-128746/4,21157.html?gclid=CM_StqietrsCFQbl7AodD1oA7g. It's abut the consistency of milk (but transparent green to aid in identifying its thickness on a mold...like candy paint, the more coats, the darker it gets) and needs to be sprayed for best results. It works as a release under polyester or epoxy resin, over just about any surface. It's water soluble and leaves no residue, so the master can still be painted easily after a mold is made.

Some of the spray-can release agents are silicone-based, and are almost impossible to remove from a plug or master.

I use an old Binks #7 siphon-feed spray gun, even on models.

Edited December 17, 2013 by Ace-Garageguy

[Ace-Garageguy]

Crisco????? Sorry had to chime in.......LMBO

Some pretty odd things have been used as release agents by guys trying to save a couple of bucks, including PAM cooking spray.

[Ace-Garageguy]

I mean creating a body, from scratch. However I understand that probably includes making a master or a buck. Is am looking at doing a 1/8 scale c cab of my own design and think it might be easier to do it that way since the body will bee over eight inches long. Thanks

Yes. You will have to build a perfect master first. There's no magic way to build a decent fiberglass part or body otherwise. You build a perfect model first, then make your molds, and then make your copies in fiberglass. It's the same basic set of steps as building molds for resin parts or bodies from scratch. No easy shortcuts.

The master can be built from special clay, over a wooden armature as shown above, or it can be built from almost ANY material that will support a surface that can be worked and sculpted to a fine finish. Bondo over urethane foam works well for models.

Old school full-scale bucks were often built with a wooden-rib framework, covered with chicken wire, in turn covered with screen or burlap, and then skinned with plaster-of-paris which was subsequently sanded to final shape, then primered and painted with lacquer. Many coats of wax were applied, and the molds were made from the waxed surface.

The full-scale plug being built in the last shot is constructed over bulkheads made from foil-faced insulating foam, hot-glued together, then covered with urethane planking as shown. That in turn gets a layer of fiberglass to stiffen the shell, and the final contours are sculpted with Bondo, then primered with polyester. PVA release agent is shot over the entire shell, and the mold is made over that. When cured, the finished mold is removed, trimmed, treated inside with the appropriate release agent, and the actual body parts are laid-up inside it.

Lotsa work unless you have CAD and a very large 5-axis CNC mill.

[Kit Basher]

Can I piggyback on this? Like Jody, I want to build a cab (for the truck in my avatar). I started a master using balsa, but I don't think it will work. Too soft and coarse. I'm thinking about carving one out of blocks of basswood, but any better suggestions would be appreciated. Does the foam/bondo method give accurate shapes? How do you carve foam? Is clay a better alternative? What kind of clay? I think I can manage the fiberglass, but making the master seems tough.

[Ace-Garageguy]

Can I piggyback on this? Like Jody, I want to build a cab (for the truck in my avatar). I started a master using balsa, but I don't think it will work. Too soft and coarse. I'm thinking about carving one out of blocks of basswood, but any better suggestions would be appreciated. I think I can manage the fiberglass, but making the master seems tough.

How do you carve foam?

Making the master is definitely the hardest part. You can make an undersized support from balsa or basswood, and skin it with bondo to develop the final shape and surface.

If you use foam, like surfboard foam (which is urethane) or URETHANE insulation foam you can sand it to rough shape with 80 grit paper. Make it undersize, and skin it with bondo or clay, and develop your finished surface. WEAR A RESPIRATOR WHEN SANDING. Also, DO NOT HOT WIRE URETHANE FOAM. IT RELEASES HYDROGEN CYANIDE GAS WHEN HEATED.

You can also use OPEN CELL styrofoam (florist foam), which CAN be hot-wired safely, or sanded to rough shape. Closed-cell styrofoam (beer coolers) can't be easily shaped with sandpaper.

. Does the foam/bondo method give accurate shapes? Is clay a better alternative? What kind of clay?

Accurate shapes? Yes. Perfectly accurate if YOU make them perfectly accurate. The foam is shaped UNDERSIZED by 1/8 to 1/4 inch, and is only a lightweight support for the bondo skin. Bondo is applied over the foam and sanded and filed to the final shape, then primered, just like doing full-scale or model bodywork. The accuracy of the bondo skin is only limited by how accurate you make it. The surface you make will be copied EXACTLY in the mold, and reproduced EXACTLY in the finished parts. Even sanding scratches will be reproduced exactly. If your plug or master has a 400grit-sanded surface, your mold AND your parts will have this exact surface.

I use bondo for smaller work because it's easy and forgiving, and I always have some around anyway. I tend to use clay for around 1/10 or so models because I have enough in stock to go that big. The stuff can be recycled endlessly if you keep it clean. It also gets expensive in large quantities, so once again, I go back to bondo for most 1:1 work where cost is an issue.

Clay is still routinely used for sculpture and product development work. The real car manufacturers used to make their full-scale models, called "clays", from exactly this stuff. Here's an excellent overview with FAQs and a catalog from Chavant (the supplier I use). http://chavant.com/new_site/files/pdf/Chavan_Catalogue_2012_High_Resolution.pdf

Edited December 17, 2013 by Ace-Garageguy

[dpride]

I recently did a 27 roadster body in glass for a salt flat racer. Here are the steps used to make it.

I drew plans at the scale I'm using, made profiles at key points, and used bulkheads made of scrap to make the frame.

Silicone rubber mold about 6mm thick.

Plaster jacket for mold with wire clips. Layup is two layers of vinylester tooling gelcoat with two layers of 225 gram chopstrand mat.

Untrimmed return.

Trimmed body.

[Ace-Garageguy]

David's got it...that's one very clean and accurate way to do it.

Beautiful, correct work. Man that's nice.

Edited December 17, 2013 by Ace-Garageguy

[my80malibu]

I recently did a 27 roadster body in glass for a salt flat racer. Here are the steps used to make it.

I drew plans at the scale I'm using, made profiles at key points, and used bulkheads made of scrap to make the frame.

Silicone rubber mold about 6mm thick.

Plaster jacket for mold with wire clips. Layup is two layers of vinylester tooling gelcoat with two layers of 225 gram chopstrand mat.

Untrimmed return.

Trimmed body.

Amazing!

[dpride]

Thanks Bill, looks like both of us have had our share of "Ford Clay" under our fingernails.........

Your avatar critter is pretty cool too.

[Bennyg]

Cool thread.

Ben

[DrKerry]

I recently did a 27 roadster body in glass for a salt flat racer. Here are the steps used to make it.

I drew plans at the scale I'm using, made profiles at key points, and used bulkheads made of scrap to make the frame.

Silicone rubber mold about 6mm thick.

Plaster jacket for mold with wire clips. Layup is two layers of vinylester tooling gelcoat with two layers of 225 gram chopstrand mat.

Untrimmed return.

Trimmed body.

[Casey]

I recently did a 27 roadster body in glass for a salt flat racer. Here are the steps used to make it.

That's the best answer I've seen posted in a long time...and beautiful work, too, David.

[pappabear1973]

That is very cool. For the most part, the body is easy enough to do I believe, it's the curve on the cowl that will make it difficult. I think it's just a hair under under a half inch radius. I could cheat and use a router on a block of wood. However I think that with the profile it might not be just right? The idea of bondo though it's good. I like your body process that you shared. What do you use to glass and hire many layers. Thank you

[Kit Basher]

I agree, way cool. Both good information and good inspiration! I may get that Loadstar done yet.

[dpride]

pappabear, the body is made from: Two layers of vinylester tooling gelcoat.

Two layers of 225 gram chop-strand mat glass.

The reason for vinylester over polester is the minimal shrinkage with VE resins.

The reason for vinylester over epoxy is the issue of bond between gelcoat and mat layers and post cure issues etc.

The C-cab would be one of the easiest to do if you used a big T cowl and the rest flat sheet with minimal bending.

If you want a T model C-cab....

Like Bills bigger projects, most compound curves can be accomplished with profiles and filling the gaps.

This another shape done with profiles and bondo. The grille shell is formed aluminum.

The key to getting the desired shape quickly is to use wipers that approximate the final curves. I use 1/8" rubber sheet cut into

small shapes or squares to do the final applications of putty. They form to the underlying shapes so you don't have to spend hours sanding

off mounds of putty.