Question about Liquid Polyurethane


Jr Member

Just a quick question. Apologies if it is in the wrong section.

I am going to attempt to apply a couple of coats of Smooth-on (or other brand equivalent) onto a foam base in the same method that X-Robots has done here:

The piece I want to coat is a helmet - namely a thor helmet.

Now I have a couple of issues:

  1. The first issue is that the piece is quite large and being able to coat it all within the set time of 3 minutes is going to be difficult - let along then attempting further coats within a time frame that will work without the additional coats not sticking and flaking off.
  2. Second issue is that the wings, although they are stuck on, are quite a bit heavier than the piece they are stuck onto - making it difficult for them to be stable without wobbling around

So my question is this:

I have the helmet formed in foam in 3 parts - the main helmet and the 2 wings - still all separate pieces. I was wondering if it would be possible to coat them all separately in the plastic and then stick them together. Has anybody ever tried that? It would make it easier to coat each piece within the time frame, and it would also ensure the small "sideburns" are solid and not so flexible to be able to stick the wings on.


Well-Known Member
3 minute pot-life is NOTHING really when covering a large prop like a helmet. You may have to apply the available material in a small section, and apply more material as you go. Don't worry though, coat 2 will bond to coat 1 no problem. Some fine grit sanding might be needed to blend the two coats. The coat bonds quite well, so it shouldn't flake off unless the piece is severely compressed after hardening. I would coat the wings separately, and then use more resin to bond the wing to the helmet, and use the remaining material to fill the joined area. It should create a nice solid bond. Please remember to brace all pieces until dried, or some part may slip and not be aligned correctly.


Jr Member
Thanks for the tips blue. I'll look at using the resin to stick them together.

I have watched a few videos about slush casting and it appears there is generally some flexibility with that 3 minutes. I think I may try a few test applications first though.

Vengeance Props

New Member
Hi, you could also look at smooth on epsilon esp foam coating, it is moisture resistant and gives a hard surface and has a 15min pot life, it drys a beige coulour but you can tint it.
Bill over at Punished Props uses it to great effect and recently did a Destiny Titan foam build on which he used it and got an amazing result.
Just throught it may give you another option.
All the best with your build.

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