[Ellie13]

Hello,
I am working on a prop that I will be putting stucco on. I need to fill the gaps between the sandwich and be able to smooth the edges (it will look like rock hopefully when done) so the stucco can adhere to something. To kind of explain it think of a peanut butter sandwich with a piece of wafer board as the peanut butter and 2" foam as the bread. The edges are cut at an angle to better resemble stone.

I was thinking of using expanding foam but did not know if it was easy to carve or if I should just piece in with the 2" pink and then cut off that excess. I will be using the wire mesh over the top of it all so maybe I don't need to fill the gaps?

Thank you!
Ellie

 

[Defenestrator]

Yes, expandable foam ('Great Stuff'; especially the 'crack and gap' version) does come immediately to mind, and I have found it relatively easy to carve and sand. Based on what I'm interpreting, simply inserting the pink foam might also work.

However, more specific feedback might be possible if some progress photos were available?

 

[Frankie's Girl]

If it's smaller gaps, I use caulking (like for bathrooms/kitchens). It dries flexible and waterproof, and is paintable. Larger areas, I would think small amounts of great stuff (and just cut/sand to shape).

 

[Sinister Sid]

I would use a combination of both scrap styrofoam and great stuff. Fill in most of the area with scap styrofoam pieces and then fill in the voids with great stuff. Both great stuff nd the styrofoam are carvable and sandable. Great stuff sands but the styrofoam sands more easily. I am not sure it is really that important what material you use if you are going to cover it in the wire mesh??. You could probably get away with using paper towels or even paper grocery bags as filler.

 

[Ellie13]

Thank You Defenstrator. I have had no luck carving or sanding great stuff What do you use to do it?
Ellie

 

[Ellie13]

Hi Frankies (c:
I did not think of the caulk. Thanks, Ellie

 

[Ellie13]

Sin Sid,
I was wondering that as well. I am worried that the stucco will crack without support. I think I will try both. What do you use to carve and sand your great stuff?
Ellie

 

[Ellie13]

Sin Sid,
I was wondering that as well. I am worried that the stucco will crack without support. I think I will try both. What do you use to carve and sand your great stuff?
Ellie

 

[Sinister Sid]

Ellie

I use a reciprocating saw (zaw saw) to carve with. Here is a link to the one I use.

http://www.homedepot.com/p/RIDGID-4-Amp-Pro-Compact-Reciprocating-Saw-Kit-R30301/100646504#.Ui-W26N5mK0

And I use a Black and Decker Mouse detail sander with a coarse grit to start with and then a fine grit to finish. Here is a link to the sander I use.

http://www.homedepot.com/p/BLACK-DECKER-Mouse-Detail-Sander-MS800B/100671602#.Ui-Xu6N5mK0

You could also probably use an electric knife? I have never tried using the electric knife (except to carve turkey and other fine foods) but I am fairly certain it would work fine. The saw I use is a one-handed reciprocating saw, it is much easier to control movement with one hand for me. You could also use an angle grinder with a sanding disc attached to sand quickly, But it is a little harder to control compared to the mouse sander.

 

[CatSkynr]

Joint Compound (drywall patch)
Can do everything you want with it. Carve it, sand it, sculpt it or just smooth it with a wet sponge. Water Soluble until ...........

Paint then seals the project.

Also - Use burlap over your project and you can coat the entire prop with joint compound instead of stucco.

 

[Defenestrator]

What I use to carve depends on the stability and integrity of the prop as well as the scale. I've used everything from a hacksaw to an old steak knife. Serrated edges do the job nicely if you're going to sand and/or patch the exposed edges.

A Dremel also works pretty well, and I'm sure the reciprocating saw would work as previously suggested, but I've not tried that one.

I've not used it due to fumes, but I would imagine that a hot wire cutter would also work just fine.

Regardless of what you use to carve or sand it, I would suggest a mask and fan to direct all of the little bits, flecks, and dust as far away from your lungs as possible. Like any other foam when sanded, it gets everywhere!