"Would These Stone Formations Be Too Difficult To Texture?" Topic

Imagine this for your 15mm SF, Fantasy, Post-Apocalyptic, etc. It is in Cuenca, Spain, at a park called "Ciudad Encantada" (Enchanted City):

link

The large concave shapes themselves should be easy, cutting 2" or 3" thick XPS (pink or blue board) with a hot wire cutter, hobby knife, etc. A dowel or long bamboo skewer* could be used to reinforce the narrower points on the foam.

QUESTION
But have you any suggestions on how to do the striations and worn "pitted" limestone texture (where the shells used to be embedded) in a realistic-looking way? Would a thin layer of wood filler take the texture, or should I consider a different material? Seen any good tutorials on this point?

Despite my plans to use these for 15mm, I would still want the texturing to be visible. Someone had once suggested using a wire brush directly on the foam, but then use a heat gun to make the holes distort and "pull" in different directions. But I've always had some misgivings about applying heat to XPS though, and ending up with loads of bad fumes or even a charred lump just as I was about to finish all the work.

By the way, this is the same place where The witch scene was film for "Conan the Barbarian", 1982. He meets Subotai chained outside the hut, next to one of those weird stone formations.

Thanks

Dan
* Dowels/skewers were used on pink XPS foam here, by this fella: link

Too easy. I'd use pumice.

link

Ochoin stole my answer.

Yep. Get a couple different types of pumice with different size grit and roll them over the surface of the foam.

Do the gouges first.

Filler with sand or pumice.

Toothbrush, wet it with lacquer thinner or anything that will melt foam and flick it. You will get random large or small holes.

There are tricks to use heat (or even solvents) to melt foam into rock like shapes.

Lots of safety warning go here:

But a torch or heat gun can be used to reshape foam (either the nice Pink/Blue type or the very cheep bead-board type EPS)

This video will get you started:
link

See about 3:40 in for the exact technique.

Ochoin stole my answer.

I am very sorry & will return it asap.

Haven't tried this, but:

Spray expanding foam filler over your frame/support. Let cure. Cut/trim with a sharp knive to shape (this also exposes the air bubbles inside.) Roughen up surface. Prime & paint.

I actually think that would work, Zephyr.

Could I propose a compromise?

Use Zephyr's expanding foam but face it with slices of pumice (cut thin…this is pretty easy to do)?

Strength & lightness of the expanding foam & the ideal texture of the pumice.

Thanks everyone!

Dan

No probs.

You'll have to post photos of your efforts.

You could also try a crumpled ball of aluminum foil: roll it into pink/blue insulation foam, to create a rough, mottled surface. Quick, easy, and safe for you, and your terrain pieces. ;-) Cheers!

Or use the reverse side of exp foam.
When it is cut you will notice that it is full of holes left by the foaming chemical. You can also press putty into it to have the reverse, so as to add detail parts.
Foam is cheap, light & doesn't easily break.
Build the base out of wet newspaper, papier mache, chicken wire, inflated kitchen gloves, etc…..
Unfortunately is cannot be shaped with heat, fire or chemicals ( believe me I tried everything).

It is easily stained ( try boot polish or thinned down black oil paint or even cheap oil based matt black undercoat paint.

Z

Z: "Unfortunately is cannot be shaped with heat, fire or chemicals ( believe me I tried everything)."

I had no idea. I was under the impression that it could be cut/carved with a hot wire cutter. Thanks for telling us!

Dan

Dan,
Could it be that there are different brands with different properties? The ones I used couldn't even be shaped with a "flame thrower" type blow lamp!!!!
Btw I also sprayed it into moulds with varying degree of success. That might be another choice.
Z

Z

Rubber molds? If so, what kind were they?

Dan

You mean what they represented?
Large boulders. I made the master out of limestone, plaster of paris & sand ( not mixed but carved limestone here, bit of plaster there, etc).
Cast in vinamould.
Sprayed foam. Let it bubble then put the card base on ( foam will stick to it , no need to glue) .
Put heavy flat peices of metal on it ( i salvaged these from an old thrown away desk lamp's base).

Varying but good results I would say.Foam does not give 100% what you would expect but what comes out usually pleases me.😉

And I do experiment a lot, not always successfully.

I had to go over them with tools before painting.

See more here.

[Url]http://castrarunis.blogspot.com/2016/08/all-kinds-of-terrain.html

Send me an email if you want more info.
Z

Z

That is awesome. I'll have to give that a try.

Dan

Thanks Dan.
You should.
The beauty of vinamould is that since it is a hot melt rubber, it is reusable time & time again.
Foam is relatively cheap but have it is better to have several projects at hand as cans do get irrevocably clogged sometimes & have to be thrown away ( I clean the nozzles immediately with acetone & a small peice of cloth wrapped around a wooden skewer.Do not throw away the cloth as the foam forms nicely on it & it can be used for terrain also 😉)
For large projects like yours you can use ping pong balls to fill the inside for a lighter build. Leave the foam to cure in the sun as it will darken to a nice yellowish brown colour, then simply wash it with the desired colour/s.

Here's another link & more exp foam stuff.

castrarunis.blogspot.com/2016/10/more-terrain.html

This might also interest you for your builds.

link

Enjoy
Z

For premade molds a common source is the Woodland Scenics line:
link

If you wish to make your own molds, I would point you to a low temp reusable mold compound. There are many sources form Japan, but in bulk needed for a scenic I suggest:
link

In the olden days we used a lot of Latex for big molds. The low cost is attractive, but only for things you want multiple copies of. The process is rather long, labor intensive, and smelly:

link

Regarding the working of different foams. The expanding foam in the can type is a Urethane, which once it is set will not melt (just burn). One can cut it with a sharp knife or sand the film surface off to expose the many random sized gas bubbles inside. However, one can play with it while it is expanding. Heating with hot air (or even hot water) will increase expansion, and cold treatment will retard it. The original type of "Guerrilla Glue" is also a good source for small work. It is very difficult to use the spray can type more than once. But two part types are also very useful:
link

link

After reading up on the Vinamold from this info page:
PDF link

It sounds very much like the same material as the Composimold material I suggested.

A self heating kettle set to 170 F is very useful for this type stuff.

Thanks for the links Dyehard,
Some very good info there which I didn't know.

Must find a supplier in Europe for that Micromark material or something similar. Getting 1 litre from US would cost an eye in shipping.

More experiments planned 😉

Z