Woodland Scenics Lightweight Hydrocal for Car Bodies

Like paper mache, it will be quite rigid.  The pattern must not have any undercut. In fact, it must have what is known as a relief angle.  The sides of the pattern must not be exactly parallel, but have a slight angle so that once static friction is overcome, the pattern will not slide along the sides of the molded part.  If that is okay then yes it should work.

It's hard to tell what you are suggesting. Using plaster and cloth or paper over a shape is a good way to make mountains and other terrain features, but the finish is arbitrary.

On the other hand, as Don suggests, objects can be cast in a mold with certain limitations. In that case, the finish is a product of the inner surfaces of the mold.

I've made simple objests like box car bodies or flat cars that way. Plaster holds fine detail well. Solving the mold "draft" problem can be achieved if you engineer the model in muiltiple pieces. An example would be a building. You can make a mold with brick detail, out of RTV (room temperature vulcanizing rubber).

Cast a supply of wall blanks and individually cut doors and windows.

If you can figure a way to put together a car body, please share. Something like a shipping container would be really doable.

'The pattern must not have any undercut'

Sounds like you are talking about a mold.No.

Ed Roth made his custom cars with plaster over wireframes or whatever was handy.

Then sealed the surface.They were super heavy to tow around to car shows.

Can we slather hydrocal over a rought foam shape and sculpt it into a car body?

Then seal it with their putty and Smooth It?

Says hydrocal can be sanded.Can it? Can it be rough filed?

Like rough file you see around? Like a cheese grater.Think they use it to make

surfboards.

Thanks.

As I understand it, Roth made the forms out of plaster and then "glassed" it.

Then he removed the plaster.

He bought a lot of plaster I guess.

If you get into this, the freshness of the plaster makes a big difference.

I used to buy it at a masonry supply house. A 25lb bag costs about $ 15.00.

We want it for a 1/8 scale car body.About 2 feet long.6-7 inches wide.

Will it work?

Are you talking about a scratch built car as opposed to copying one?  Why use a material like paper mache or hydro?  You would have a real problem carving it right before it begins to set up.  Why not go the other way, and just carve it out of wood?  Or, as car designers used to do for models, make up a wood buck, then sculpt in clay.  Then, for a permanent final model, make female plaster mold and use that to make a plaster model. I believe plaster is probably the cheapest material to create a model with, but you must cast it into a mold.

 That was the way many contestants in the Fisher Body Contest made their models.  I had learned carving from my early modeling days, so just went ahead and carved wood, but many folks afraid of carving wood went the clay route and mold and plaster cast.

Hmmm, I used to run with a crew of designers from SoCal who came out of the design office of Charles and Ray Eames. A few of them studied at Art Center College of Design, a feeder for designers who went to work for the design houses like Fisher.

I took a tour there one time, and saw the car design studios. The students were making car body models about the scale you describe, the final models were made by the school shop out of fiberglass from the clay models. Then hours and hours of polishing. They called it "stroking the dolphin's head".

Okay.Lightweight hydrocal is sidelined as a way to build 1/8 scale body.

Yes.We have a couple Craftsman Guild contest booklets.

They use wood for the buck.We will use foam.

My takeaway from it was to use their method of getting the two sides to

match.

That was sort of a concern of ours.