what is the best way to apply hydrocal rock cropping to a styrofoam mountain?

[Anonymous]

I am new to working with hydrocal and I am wanting to know what would be the best way to apply hydrocal rock castings to a mountain that is made from styrofoam? Any advice would be greatly appreciated.

thanks[:)]

[csxt30]

[#welcome] Dgvincent ! I'm not sure the hydrocal will stick to the styrofoam, so you might take a piece of styrofoam & wet it & then wet your hydrocal rock casting down on the back side & mix up some more hydrocal & put it on the back of the casting & try to get it to stick there. Sort of a test. That's the way I have been doing my mountain, but mine is all plaster cloth & hydrocal. I did have to hold them there by hand & after the first bottom one, they might sit right there till the Hydrocal sets up in a couple of minutes. Here's a picture of mine, with a lot of work to do yet on it. Hope this helps & others come with some info, too !


Oh, be sure & click on to see the rocks I added.

[Anonymous]

You can paint on a thined down layer of hydrocal with a brush and allow that to dry and then appy the rock castings to this material.

[zeames1]

Just got done doing what your trying to do this weekend. The method I prefer is to cover the styrofoam with plaster cloth or Rigid Wrap, then apply a thin 1/8 - 1/4 inch thick layer of Sculptamold, which when mixed in proportion to the directions is a plaster like material that gives you plenty of set up time. While it is still wet, just press the plaster outcroppings where you want them and they will stay put. This also allows you to be able to work the surrounding landscape right up to the casting in a very realistic manner. Both Sculptamold and Rigid Wrap are available at most craft stores. Check out the Model Railroader DVD series Dream, Plan, and Build. The first in the series has some great instruction on doing this and other scenery techniquies.

[thor]

This is an oblique answer because my assumption was that you were asking what to use to stick pre-made hydrocal castings to styrofoam? I further assumed that your question was more about what adhesives are safe on styrofoam?

Okay, well the two adhesives that I know are safe to use on styrofoam are white glues like Elmers (PVA glues) and epoxy resins. However if you really must use a petroleum based contact adhesive, the smelly, grabby stuff that sets up immediately, you can coat the styrofoam first with Elmers or even a latex paint and then once dry it will act as a barrier and stop the adhesives solvents from attacking the styrofoam. I like to use artists spray glues a lot and they eat away styrofoam big time, so I always paint my foam first then I can spray with no problem. I also use this barrier technique for spray painting my scenery with rattlecan paints because it dries fast and you can get nice shading effects and so forth. I use paper a lot for modelling and scenery and those spray paints stiffen it up without the distortion that water based paints would cause.

[Roger Bielen]

I used spackling compound and let it ooze out around the castings and then blended it into the castings. This way I didn't have to worry about the castings butting together perfectly.

[marxalot]

dgvincent,

When I worked with hydrocal in the past I found it to be too hard to readily accept most stains or thin paint washes. I used it as the sub base and then covered it with plaster or sculptamold. The rock casting were in plaster also........ for what it is worth...............

Jim

[csxt30]

Marxalot : I have been using the Woodland scenics liquid pigments in my rocks & that really works good. I daub it on with an old sponge & thin it a little with water. I have Yellow ocher, slate grey, concrete & raw umber . I just can't seem to take a good picture, but I will try again. If I cover it with sculptamold, I believe I would loose all the little details from the mold. Thanks, John

[marxalot]

QUOTE: Originally posted by csxt30

Marxalot : I have been using the Woodland scenics liquid pigments in my rocks & that really works good. I daub it on with an old sponge & thin it a little with water. I have Yellow ocher, slate grey, concrete & raw umber . I just can't seem to take a good picture, but I will try again. If I cover it with sculptamold, I believe I would loose all the little details from the mold. Thanks, John

I agree that you loose detail with any covering on a rock mold. I just stopped using hydrocal for the rock molds and used regular plaster of paris. Good detail and it would accept my arcylic washes............

Jim