I got a big board of white Styrofoam as packing material with a fridge I just bought, and I would like to try and use it to make some buildings. My question is.. if I apply plaster on the foam to give it texture, does it stick to it, or will it just peel off after a while. I'd hate to go through the trouble only to have it fall off later!

Also.. it is about half an inch in thickness.. would that be an appropriate size for a modern building in 1/35 scale?

Thanks
Hisham

I use those materials for model railroad scenery, and they stick together just fine. The problem is that neither is strong, so if you bend, crush, or poke it, it'll crack apart on you, exposing the white under the paint, so be sure it's not treated roughly when you're done.
Half inch seems thick to me for a wall, but I don't know. I'm sure walls come in all thicknesses too.
-Sean.

Hi Hisham I only use styrofoam as a base material in dioramas. It's great for creating different levels without the weight that plaster or wood on their own would have. I usually cover it in plaster. If you want the plaster to really stick to it then scratch the surface of the styrofoam with a toothpick or something. The only problem I would see in using it for walls is that if you bump anything against it then the plaster will crack. Also half an inch with plaster on either side seems a little too thick for a modern wall

I had limited success with gesso over styrofoam - the latter had to be really finely sanded and gesso had to be applied in a minimum of 4 coats until it began to look smooth. I found gesso a lot finer substitute when portraying relatively smooth surfaces of structures in scale and it's a lot more pliable as it dries.

Fine granulate or pumice can be mixed into gesso to add surface when imitating cast concrete etc.

I guess the only limit is the amount that it takes to cover the same surface over and over, but the end results are a lot more durable. As it tends to contract some when drying, it's important not to apply it over really subtle details (I guess no worry with styrofoam).

Thanks for the advice, guys.

As for the thickness, the building I live in now has the outside walls built with bricks laid down sideways.. so, the thickness of the wall would be the length of the brick (25 cm) plus a layer of mortar on both sides.. so around 30 cm approx. So, how much is 30 cm in 1/35 scale?

I do remember the buildings in Lebanon, were I was born and raised, having thicker outer walls, though. They build with large (hollow white) stones there.

Hisham

Hi Hisahm -

I just did this the first time myself. It FELL RIGHT OFF! It cracked and came apart. I used STUCCO, Self Hardening Clay, PLASTER and the Light Weight Spackle. I used EACH one seperately to see how it worked with the styrofoam. HOWEVER I LEARNED FROM MY MISTAKES. Is what i tried after all this failure was to roughen up the walls FIRST, THAN I applied white GLUE, than put the plaster on over that. I also rubbed some of the glue into the clay for the part I put clay on. (I put clay on one part and plaster on another, stucco on another wall etc). the PLASTER also cracks though as does the clay. I did find that if I took some of the clay and mixed it with water, making a yogurt consistency mixture, I could rub that onto the clay as it dried over any cracking parts. This helped greatly to reduce any cracks. i rub it on smmothly with toilet or tissue paper. Hope this helps! check out my building in the forum for Constructive Feedback.

http://armorama.kitmaker.net/forums/168288&page=1

David

Well, half an inch in scale is is 17 and a half inches full-size (44.45 cm), so that does seem a little thick for a residential building wall, unless it is a multistory masonry building (i.e. no steel structure). The ground level walls must carry the weight of the upper stories, and are consequently thicker.
As others have suggested, styrofoam has little strength, and might be better suited for sculpting terrain features, overcoating it with plaster or other ground cover material for texture.

Just a bit of useless information Hisham, a standard house brick is sized at 9inches by 4 inches plus the mortar between,I can,t do cms ( to old to change now ) hope this helps

Hej Hisham.
Just save the styrofoam for adding height or elevation to your bases.
In my opinion, its too thick and involves too much risk with your work cracking or flaking off. Its better to use foam board, cork, stiff cardboard or thin laminate to be the skeleton for your walls.

Thanks for all the advice, guys. I guess I'll just keep it for building up groundwork.

One more question.. I was at the stationary / art store the other day and I saw these boards which look like Styrofoam "sandwiched" in between cardboard (Don't know what they're called in English). Are those suitable for building walls with? If so, do they need to be covered with plaster or any other material, or do you think the outer layer of cardboard could work as the outside of a building wall? I have to say it does look a bit too smooth!

Thanks again
Hisham

Yes, in English, that's the "Foam board" that Frank referred to. It's very strong and durable, but you'd have to put a texture on it, because you're right, it's very smooth. Being paper, it should take paint, glue, or whatever very well though.
I admit I haven't used it myself.
-Sean.

Hi Hisham,

Depending on the foam you are using it works just fine. Just make it as thin a layer as possibly and add a bit of Elmer's glue to help with the adhession. Here's a reference pic for you. Trust me, after seeing guys use this stuff I wished I had done this with the "Hue City" dio. That beast was all scribed plaster slabs and very time consuming. So give it a try and get after it!


Cheers, Ski.


P.S. As you can see it works just fine, but blue constrution foam will probably be your best bet.

Yes, I've seen many dioramas where foamcore was used to create strong, lightweight building structures. You can assemble it with ordinary white glue or epoxy, and it can be pinned together while the glue dries. The paper cladding adds a surprising amount of stiffness. And yes, you could certainly add a layer of texturing material without making it unrealistically thick. In addition to ordinary plaster, consider wall patching compounds (which often contain plasticizers that improve adhesion and add flexibility and strength), or epoxy putty (if purchased in larger quantities, it's economical--it just becomes frightfully expensive when you buy the tiny amounts sold under some hobby labels). Aves Apoxie Sculpt and Magic Sculpt are two brands that come to mind, and Milliputt is widely available in Europe (it's made in the UK).

Try this. Cut toothpicks, so that they insert deeply into the foam and have about 1/4" left sticking out. Space them 1" apart. Lay plaster down to half the height of the toothpicks. Put cheese cloth over this, so that the toothpicks keep it taut. Put another layer of plaster down to the top of the exposed toothpicks. This is how concrete is reinforced with metal rebar. Should work for plaster.