resin on foam

[rexel13]

Hey. So I'm sure this has been addressed, but I can't find a clear answer.

Is it possible to coat a foam build with resin or fiberglass or some sort of cover coat to harden the foam? If so, any tips or tutorials would be awesome.

Again, if this has been covered, I apologize and would appreciate being pointed in the right direction.

 

[-VERTIGO-]

If you look at XRobots and DocHoliday's threads you'll see the processes they use. Doc used a rondoing method, and XRobots used a method with Smooth-On, both threads are worth a look to see what you prefer. If you want to see the results of a fully done helmet take a look at Shelfside's thread.

 

[Cooper648]

I have been working on a mark 42 Iron Man helmet and I have just coated it with the first layer of fiberglass resin and I just got to say that it works amazing! Once I had the EVA foam helmet built, I coated it with 3 layers of PVA (White Glue) using foam paint brushes to protect the foam and fill in dents and foam imperfections. I then coated it with 1 coat of fiberglass resin which I found at Home Depot for a very cheap price ($14.99). It included the hardener and everything I needed. I used a bristle paint brush to spread the resin and then I used a smaller one to get into the harder to reach crevices on the helmet. I highly recommend investing in a ventilator ($19.99) if you don't already have one cause this stuff gives off a very powerful smell. After the resin dried, it still had a bit of a flexible feel so I think 2 more coats will make it rock hard. Once its solid I have some bondo spotting putty that I got from a local auto-body shop that I plan on using to fill in any pinholes and the like. Buy plenty of brushes as you will burn through them, or buy some acetone to clean your brushes with so you can use them again and again. I hope this helps, let me know if you have any more questions or concerns!

 

[Biskt]

Cooper, when did you flex it? How long after you had painted it? Just because it is touch dry does not mean it has cured. Leave it a few days and flex it, it will crack. Still, I'm wondering how many layers would stop it from cracking...

 

[The Armorer]

I'd just like to say, that I too have tried a sample of resin on foam... and I really want to know who started the rumor that resin eats through foam

Yes, after one layer it cracked when I flexed it, but, if I put a layer of fiberglass cloth (or just bondo) over it, it would become the same as pepakura with paper, it wouldn't flex, but it would be hard as a rock with it's own padding built into the piece.

I don't know if I'll use it when I get to foam building, but, I just wanted to say. I"VE BEEN LIED TO!!!!

-The Armorer

 

[clonesix]

I will repeat this here, as it is applicable: There is MORE than one type of foam, and MORE than one type of resin! My beer has foam, but you can't build anything with it.

When you hear that resin melts foam, it refers to Expanded Poly Styrene (EPS) foam. It is melted by ANY solvent, but specifically polyester resin! Not epoxy resin, nor polyurethane resin.

Without any specifics, it is hard to address your question. In this case, I will assume that you mean EVA foam, and polyurethane resin. There are many different "Shore" values for urethane, and the higher values will crack when flexed. Lower shore values can be found, or a higher shore elastamer can be used, but honestly White Glue works well for this and is much cheaper.

The idea of coating the outside of a Pepakura build with fiberglass is counter-productive! Adding a layer of fiberglass to the outside gives you more work to do, as you will get an uneven surface that needs to be sanded and filled and smoothed. IMO, NOT worth it.

 

[The Armorer]

Yeah, I know what I'm doing, I've done fiberglass work before. Before my so many months and over three hundred posts on this forum, I accumulated over 400 posts and quite a rep (not to brag) on the 405th. I was just suggesting a way to make it stronger = no flex at all.

And about the foam, yes I mean what I tried it on was EVA, I have heard (for years) that eva can't handle fiberglass (polyester resin), so that's what I was 'mad' about .

NOW... The question is. What shall we do with this enlightenment? Also, Smooth on has a new plastic coating that is for EVA foam, and turns into a bondo like hard shell. So there's more food for thought.

-The Armorer

 

[Ryss]

Also, Smooth on has a new plastic coating that is for EVA foam, and turns into a bondo like hard shell. So there's more food for thought.

Epsilon? I'm interested to see if it'll catch on...

 

[Cooper648]

Let me rephrase. It is not flexible at all, it is actually very rigid. It just has a little push to it that you can feel when there is a thin coat of the resin on the foam. I bet once I put on a few more coats on, it will be rock solid.

 

[SqueekinOrka]

I plan on coating my foam build in 3 layers of white (PVA) glue. But I've heard if it gets wet it will become sticky and if temperatures are high it will be glue again. Would primer be able to provide a waterproof coating and prevent it the glue to become I assume runny and well... glue like ? Plus It will be painted also.

 

[Cooper648]

Are you planning on coating the glue with resin?

 

[Lflank]

> I plan on coating my foam build in 3 layers of white (PVA) glue. But I've heard if it gets wet it will become sticky and if temperatures are high it will be glue again.


Never had any problem with either, and I live in Florida, where thunderstorms and 95-degree heat are everyday things.

 

[SqueekinOrka]

Are you planning on coating the glue with resin?

At the moment I'm not to sure what to coat it with. Would resin work ?
Lflank. Do you just apply the 3 layers of white glue then simply paint over it ? Or do you apply something over the glue then paint it ?

 

[Cooper648]

At the moment I'm not to sure what to coat it with. Would resin work ?
@Lflank. Do you just apply the 3 layers of white glue then simply paint over it ? Or do you apply something over the glue then paint it ?

When I work with foam I coat the outside of the piece 3 times with PVA glue to cover up and scratches or foam bubbles. Then I coat the entire outside of the piece 3 (or more if need be) times with fiberglass resin($14.99 for 32 oz) using a bristle brush. You can buy a bunch of brushes or some acetone ($9.99 for 32 oz) to clean em up so you can use them again. If you do decide to work with fiberglass resin you must invest in a ventilator ($19.99) as this stuff can really hurt you especially if you sand! Once the resin is hard, you sand and rub Bondo spotting putty($7.99) on it until its perfect. You then paint it and you should be left with an amazing piece!

 

[SqueekinOrka]

Nice all that seems to be very easy to get. That's perfect. Thank you for the help

 

[Lflank]

Lflank. Do you just apply the 3 layers of white glue then simply paint over it ? Or do you apply something over the glue then paint it ?

Just glue, then paint.

I usually layer the inside with pieces of cotton cloth soaked in glue, to stiffen it.

- - - Updated - - -

When I work with foam I coat the outside of the piece 3 times with PVA glue to cover up and scratches or foam bubbles. Then I coat the entire outside of the piece 3 (or more if need be) times with fiberglass resin($14.99 for 32 oz) using a bristle brush. You can buy a bunch of brushes or some acetone ($9.99 for 32 oz) to clean em up so you can use them again. If you do decide to work with fiberglass resin you must invest in a ventilator ($19.99) as this stuff can really hurt you especially if you sand! Once the resin is hard, you sand and rub Bondo spotting putty($7.99) on it until its perfect. You then paint it and you should be left with an amazing piece!

I think that defeats the purpose of the foam, which gives a nice smooth finish without any sanding. To strengthen pieces, I use either fiberglass resin (just the resin, no cloth) on the INSIDE. Or more usually I soak pieces of cotton cloth in PVA glue and line the inside with that. It stiffens and strengthens just like fiberglass, but is cheaper, lighter, and easier to work with.

 

[SqueekinOrka]

If the glue gets wet it doesn't become sticky ? Does the paint act as some kind of seal/protection for the glue ? (Sorry for so many questions).

 

[Propsjonnyb]

Plain Tissue is much better, it's much more flexible than, cloth or cotton fibre , oh and don't buy the patterned stuff - unless you want you leg pulled !! Once you've got a coat of resin on , apply car body filler ( P38, Bondo , plastic padding, plumber's putty ((what ever your preferred filler is )) one coat and sand smooth that's all you need to do inside , prime, paint and finish , line with foam or a hat-rig harness and your helmet ready to wear !

 

[rexel13]

I appreciate all of the feedback. Thanks!

 

[I Mentz I]

This is great info.