Sealing foam before painting?

I am about to build a Dredd armor out of foam for halloween and I was wondering what the best way to seal the foam is before painting?

I seen dilluted white glue, is that as in Elmers glue dilluted with water?

Also plastidip, but I am worried it might peel? has that happened to anyone?

Any advise for a first time foam builder?

I did foam carving in Orlando and in the shop I worked at we used elmers straight out of the bottle. Once it was dry we could safely fiberglass it.

Rosco Flexbond. It looks and smells just like white glue but way better sealant.

I know most people want to retain the flexibility of the foam, but I was wondering if anyone has had any luck actually putting fiberglass resin onto the foam to harden it? For a build I'm working on, I'm just using the foam for the simplicity of the raised details, I don't want to glue together all the tiny pieces in pepakura. I don't want my armor to be flexible though and I want it to paint really smooth, even be able to put bondo on it. Has anybody tried it? I saw a video where a guy tested out some resin on craft foam, but it was just a sheet, not an actual armor piece.

@Risu

In theory, what you want to do, should actually work. I've seen it done in the past.

Check out this Thread
405th's JEDI STUMPY's helmet build
Jedi Stumpy's New Mkvi Helmet New Update 12/3/09 Molding Done! Casts Have Been Pulled!!

Thanks for the link. I did that same thing when I attempted a Chief helmet and the super glue did harden the foamies, that's what gave me the idea. After seeing your tutorial series on foam armor building I decided that was the way to go and I'd give it a shot. I'm not sure though if the FG resin will soak in as well as the super glue.

a couple of coats of plastidip has never peeled on me.
and i've put some of the armor i have made through a lot of work.

awesome thanks for the replies everyone! I will post a WIP once I start on this

As a word of caution, I would try your sealant of choice on a scrap of your foam first. I have had bad experiences in the past where I tried to do exactly what you are talking about and ruined the piece I spent a had carved. I did like you and read on a forum that this would work of that would and it didn't, only to find out later that I wasn't specific enough about the type of foam, etc.

We're finding with our foam build that tape does not stick to it at all, so we're testing plasti-dip to see if adhesives stick better to that. It's drying in the basement now, ready for a test of the decal material tonight.

roccopeterbilt said:

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As a word of caution, I would try your sealant of choice on a scrap of your foam first. I have had bad experiences in the past where I tried to do exactly what you are talking about and ruined the piece I spent a had carved. I did like you and read on a forum that this would work of that would and it didn't, only to find out later that I wasn't specific enough about the type of foam, etc.

Great advice. I always test products on foam scrap prior to treating the final pieces for the same reason!

Also note, that all foam is not the same - Foamies, floor matts and the stuff GraphicJordan (and I) use are all different so they may react differently to different compounds.

The EVA closed-cell foam that GJ and I use didn't take the fiberglass resin for me very well -- as I use some latex caulking to smooth out seams in the foam pieces. The resin reacted differently to the caulked areas and non-caulked areas so it didn't end up being a smooth or evenly-drying result.

I HAVE had luck with 2-part epoxy as a hardener. I use this and sometimes extra materials (like thick plastic and/or metal washers) to strengthen connection points.

As for plasti-dip, I've never had it 'peel' on any pieces - although I don't have a lot of wear-n-tear on any of this armor yet, so it's very 'untested'.

noted