I know this subject has to have been covered, and probably at great length, but I am not finding much of anything.
I’m modelling a large arched concrete bridge in the blue Formular extruded foam and would like to find a few tips on how to make it look as much like old concrete as possible.
Can anyone point me in the right direction?
Thanks!
In terms of texture, it’s pretty good as is. Just paint it. However, it’s also common to coat it with vinyl patching concrete, or there’s some stuff you can get from the Hot Wire Foam Factory folks. I got some for review once and thought it was pretty good. I gave it to my dad who was rebuilding his Cinderella’s Castle, and he said it was great stuff to work with. (And he’s done a lot of styrofoam/concrete buildings.) BTW, if you want to borrow my foam cutter, let me know.
Later,
K
(http://freightsheds.largescalecentral.com/users/dieseldude/IMG_2906.JPG)
I made this viaduct out of blue foam a little while back. Initially, I coated it with sifted hydraulic cement- a technique I read about in GR magazine (sift cement on foam then mist with water). It looked great… until I tried to move it into place. Not so great! The hydraulic cement cracked- everywhere. I’m sure that the cement will probably work well on smaller structures, but this monster is made up of two 7 foot sections. In the end, I ended up painting the foam with waterproofing hydraulic paint. The kind that you use for basement walls. It has a heavier texture than normal paint and looks bettere than cracked hydraulic cement. Hope this helps.
-Kevin.
Thanks to BOTH Kevins!
I’m going to post pictures once I get the basic structure in place (it turns out I needed to use 1/8" masonite for the arches because the 1/2" foam wouldn’t flex enough without deforming and/or breaking, however I’m using the 1/2" extruded Formular foam for the rest of the structure) and then I’m going to try both materials to see which one works best for me and this project.
I’ll be back.
I bet you could use the textured spray paint for the texture and if you cant get the right color, then paint over it with the right color.
Textured spray paint will work good on the masonite, but don’t get any on the foam- the solvent in the paint will eat the foam (trust me).
-Kevin.
Jake Smith said:
I bet you could use the textured spray paint for the texture and if you cant get the right color, then paint over it with the right color.
Thanks Jake…I think it’s probably better to paint first if you use textured spray. The reason I say that is what Kevin mentions about the solvents eating away at the foam.
I’m noticing that the foam has a tiny tiny cellular-type structure, which probably accounts for its strength and light weight, being mostly air, and when I sprayed a test block of foam with spray paint, the paint seems to make it’s way into those cells, little “holes’” and make them bigger and more noticeable. Not really a good thing unless that’s the effect you’re after.
On the other hand, those tiny cells, as well as the rough side of the masonite, would probably take the applications both Kevins are taking about. Then I’m thinking base coat of the camoflauge paint over the application once it dries thoroughly. The camoflauge paint is so nicely dead flat, matte, and then maybe some texture paint. Then color from there.
My little problem at the moment is that I made the arches on the bridge too narrow and pointy instead of broad and stable. Now I got to re-do them; not a big deal but I lost a couple of hours work. Dang. I’ll never make that mistake again…who would have thought there was so much math and engineering in a simple arch? I’m loking forward to getting the engineering over with and a base coat down…then I’ll finally be in my element, painting!
I would not think masonite would be a good choice for outdoor use, it won’t like getting wet !
You have to remember that in 1:1 scale, concrete is relatively smooth on structures that are built with it and were intended not to have any facing, brick, stucco, etc., etc. I cannot say for sue but I believe Kilz spray primer is alcohol based. I don’t believe alcohol will dissolve Styrofoam like solvent based spray paints. Particularly spray paints that have a lacquer base. Once you have primed the structure, you can spray it with whatever color you prefer.
Concrete in the real world, especially on bridges is kind of tan/grey……………… It will also have rust stains running down some parts of it no matter how diligent the maintenance crew is.
dieseldude . said:
(http://freightsheds.largescalecentral.com/users/dieseldude/IMG_2906.JPG)
I made this viaduct out of blue foam a little while back. Initially, I coated it with sifted hydraulic cement- a technique I read about in GR magazine (sift cement on foam then mist with water). It looked great… until I tried to move it into place. Not so great! The hydraulic cement cracked- everywhere. I’m sure that the cement will probably work well on smaller structures, but this monster is made up of two 7 foot sections. In the end, I ended up painting the foam with waterproofing hydraulic paint. The kind that you use for basement walls. It has a heavier texture than normal paint and looks bettere than cracked hydraulic cement. Hope this helps.
-Kevin.
That’s a nice looking piece of civil engineering Kevin
Thanks, Dan.
-Kevin.
