Foam Hardening Question

Well i want to make a new build for iron man mark 7, and i want to do it out of foam.
but i want select pieces, if not majority of the pieces to be hard and rigid to help with the look and shinyness of the costume.
i KNOWWWWW there is no point in having a hardened foam costume but i find it easier and the inside of the foam would still be nice and soft against my body... ANYWAY


i was wondering if you guys know of a way of hardening foam to a hard plastic quality that i may not know about.

i know fiberglass resin warps it..
and i have watched xrobots and his smooth-cast tutorial.
i was thinking thin layer of papermache then fiberglass? help meeeee

Xrobots method is the best, and a gallon kit of smooth-cast should be more than enough to do a whole suit. Leave key areas un hardened for flexibility, It is what I did for my Fallout Power Armor, and my Iron Man mk 42 suit.

While I haven't tried it, I have seen youtube clips of someone applying one part wood glue and one part water in a few coats on the finished foam product.

It has been a while since then, but I think it was Stealth who posted the video ...

While I haven't tried it, I have seen youtube clips of someone applying a mix of one part wood glue and one part water in a few coats on the finished foam product.

It has been a while since then, but I think it was Stealth who posted the video ... he has a thread about Iron Man Foam.

Edit: sorry about the double post.

okay thanks guys, but if thats the only way to do it, can you give me a bit of help in terms of Polyurethane resin?
I know xrobots uses Smooth-Cast 65D (which is about 90$) and i heard others use EasyFlo (which is about 45$)

But the sad thing is, is that i cant get those because i am in Canada..

MY QUESTION IS
Is there a cheap Polyurethane resin that i can get here in Canada?

Epoxy resin doesn't ruin the foam underneath Always find out the type of resin, as fibreglassing can be done with polyester (which dissolves polystyrene which is why it is not used for many industiral applications) and epoxy resin the latter of which soaks nicely in to card, foam, polystyrene, fabric etc.

You can also use the foam as a base to glass over. Fibreglass tissue is a very fine non-woven glass cloth that can make a super light layer to capture the shape and then you can pull the foam off the back (depending on how well you worked the resin in to the porous surface) and back fill with cloth and/or heavier matting. You may want to do more than a single layer of tissue

Direct modeling and temporary molds with fibreglass « The Plain Jane Costume Chronicles
I am in love with using foam core board as it keeps such a defined blocky shape and makes a super light piece of armour/prop at the end. You only need two layers of 100gsm cloth on each face (inside and outside) and it is rigid and takes a lot of effort to break. But you do lose some of the flex you would get with "just" matting.

I have used some fiberglass cloth and resin before, but I'm more wondering about coating the foam,

I know you cant use fiberglass resin on the foam because it will warp it and stuff, but then i heard about the Polyurethane and pva method, can anyone expand on what i should look for? and being cheap would be nice lol :rolleyes

I would try multiple methods on a test sheet of foam. That way you can see firsthand up close which works best for what you need.

Have you looked into hard rubber for the sections you want stiff?

I have read that some people are trying EPSILON to coat and harden their foam but I am not sure what the consensus is on just how viable of a solution it is.

I use pva then styrospray then bondo. It does fine. A few coats of pva then rondo then bondo is the cheapest way to go...and it sands better than any of the plastic products i have used. They seem to heat up and melt on the foam if doing a lot of sanding.

Ooh! Ooh! I have a great solution! Have you heard of Worbla? If you're not strapped for cash it works perfectly to make foam hard and smooth. Worbla is a thermoplastic that comes in sheets. One side is more adhesive than the other. Heat it with a heat gun and it becomes super malleable, to the point where you can even use it like clay! It forms a super strong bond with itself, and you can reheat it as many times as you want. It's super easy to work with and emits no fumes. When heated it stretches and does compound curves very well, and you can squish the seams together so they become almost invisible. The surface of the Worbla is sorta rough but that can easily be fixed with several liberal coats of gesso (and I'm guessing also bondo, haven't tried this myself yet), and then some sanding. The final product is very rigid and durable. I covered a piece of 5mm foam armor with it and you can't bend it at all! I curved the Worbla over the edges to the inside slightly which provides more structural support. I would imagine that not doing that would make the armor slightly bendy depending on the shape of it. Worbla on its own is still quite flexible.

Here are some pics of my armor. They were already plastidipped and painted but the paint was cracking so I'm covering them in Worbla and will re-paint. Since I took these pics I have finished covering that one that's partially done, gesso'd it, and sanded it (going to fix some areas with bondo).



The Worbla also allows you to shape the foam in ways you couldn't easily otherwise. Note the indent in the side of the Worbla-covered one in the bottom two pictures. After applying the Worbla I reheated it and bent that part inward to allow it to better sit against my body (these are upper arm armors so they hit my ribcage).

Let me know if you decide to go this route and have any questions! I'm more than happy to help.

texxxan said:

I use pva then styrospray then bondo. It does fine. A few coats of pva then rondo then bondo is the cheapest way to go...and it sands better than any of the plastic products i have used. They seem to heat up and melt on the foam if doing a lot of sanding.

Click to expand...

RONDO? that being a mix of fiberglass resin and bondo? right? im sure i could try that, it just seemed that resin would be that way to go lol maybe im wrong..

and alright... no clue what styrospray is lol
but i would look into it if its possible to get from like... home depot or rona or whatever.... their website is down right now however, ill look as soon as possible...

If i WERE to go the polyurethane resin route. would any kind of "polyurethane resin" do? is there a difference? whats the difference between smoothcast and all that junk? :rolleyes

Elmer's Glue All glue works pretty good. My Mark 42 looks and feels like plastic. I only used 2-3 layers...



I've tried the smooth-cast liquid plastic way once and it was too much of a hassle and wasn't satisfied with the end result. It's more rigid but it can be a pain in the butt.

FatMan said:

Elmer's Glue All glue works pretty good. My Mark 42 looks and feels like plastic. I only used 2-3 layers....

Click to expand...

although it may look and feel like plastic.. it isnt ACTUALLY plastic lol which i dont like lol

want to bump this

check this video out. i have'nt try it yet

Resin coating Styro-Foam Props - YouTube

Fambini said:

I have used some fiberglass cloth and resin before, but I'm more wondering about coating the foam,

I know you cant use fiberglass resin on the foam because it will warp it and stuff, but then i heard about the Polyurethane and pva method, can anyone expand on what i should look for? and being cheap would be nice lol :rolleyes

Click to expand...

Yes, you can use fibreglass resin on foam like I said use epoxy. That's why I said to find out what kind of resin people have been using that causes warping. Epoxy does not harm any foam.

bryanjas said:

check this video out. i have'nt try it yet

Resin coating Styro-Foam Props - YouTube

Click to expand...

hmmm thanks for that video.
So what im getting from a couple other sources, is that ANY polyurethane resin will do? just those ones are recommended?