"Help!" for: Foam


Sr Member
This thread will contain general first hand knowledge of producing armor or weapons with various types of foam.

People who don't know: Post questions.

People who know: Answer those questions.

Please be as clear and detailed as possible with your questions and/or answers. Repeated questions or variations of certain questions may be consolidated over time into an FAQ section in the post following this one.

Always ask and answer questions as if you were asking/answering your mother or grandmother. In other words, politely.

Rudeness and/or impatience will be met with an infraction. You don't want too many of those.

These threads are meant to reduce and hopefully eliminated the need for the numerous 'I need help threads' that seem to generate endlessly in this section of the forum.

They are not a be all, end all to all questions that could ever be asked though. Some questions will be project specific and you may need to ask those IN the project's thread itself. However, some may not see your questions there so you may post a link to said project thread in the appropriate "Help!" thread when you need the attention of a few extra eyes.


Jr Member
I don't think your supposed to use the caulking to seal the foam but latex based caulk is good for filling gaps left by cuts and such. For sealing the foam people mostly use either PVA glue or Plasti-dip which is like a rubber in a can. But PVA is the cheapest sealing method. I have no idea about the spackling XD

Caboose vs Grif

Well-Known Member
Yeah, haha. I meant to full in the gaps left from the cuts. I use plastidip to seal my foam. Thanks though!


Well-Known Member
If I may, my foam tutorials have received some good reviews so feel free to follow the link in my signature to the tutorial thread for the YouTube link


Well-Known Member
How do I use caulking to seal my foam? Is there anything cheaper that I can use? Ive heard that you can use spackling also. Is that true? I use this kind of foam http://www.sears.com/rollup-mat-shock-athletic/p-00614724000P?prdNo=11&blockNo=11&blockType=G11
You can use it to seal your entire foam piece. I've used it as well as hyperballistik and we have both had great results. You should use Alex Plus silicone caulking from Walmart.

Get a bowl of water and a sponge. Squeeze a small amount of caulking out onto the piece you are sealing, wet the sponge and squeeze it out leaving it damp. Then start rubbing the caulking around filling in small recesses and pin holes, even "little" gaps where you joined foam together. When you are finished, the part should have a "slight" white haze over the entire piece, as though you spilled paint on a floor then tried to wipe it up. Do not leave alot on the part, because if it's thick it will crack and that's not good. Hope this helps and I hope I explained it good. Let me know if I need to explain it better. :D

As far as the spackling goes, if you're talking about drywall mud, I wouldn't use it because it's not flexible, thus it will crack...thus...that will suck. :D


Jr Member
Hey guys, I'm relatively new to the pepakura/foam building. I recently made a Dead Space 2 Engineer Pepakura set as that's what I plan to make, but there are so many small edges and extra parts dangling here and there, all over, and making full pepakura shapes out of them is not only a huge waste of paper, but tedious as well cutting hundreds of tabs. ;___; So I was planning on jumping into this foam building. I've been watching tutorials and reading up but no one seems to cover the hardness at the end of the process. This suit will contain many hanging parts (whereas Spartan and ODST suits are relatively solid shapes) and I will need to be sure the suit will remain tough, rigid, and intact.
- How hard will the foam become after Plasti Dipping?
- Is there something I can use to glue each part to another and keep this sturdiness through and through after they have been Plasti Dipped? I plan on doing piece by piece and once they are hard, I will attach them together, but I'm not sure which glue would be best as Hot Glue has a chance of me banging my arm or RIG against something and off goes a piece, you know? Perhaps Gorilla Glue?

This is my first foam build, so any tips would be greatly appreciated guys. Thanks =]

DBMike, the tutorial was a great help. You knocked out 90% of my questions. =P I went over to RoxyRoo's "Building Armor with Foam" and she knocked out another good percentage. I almost feel ready to jump in already! I'm only worried about how hard the pieces will become and what can be used to keep them together and solid... Hell, would screws work? Perhaps it'll help give it a mechanical appearance.


Well-Known Member
STATYK- glad the tutorial helped.

I have seen people use bolts, basically use a piece of plastic as a solid layer between bolt and foam so it acts like a washer and doesn't just pull through the foam. That could definately work out.
As for the toughness of the foam, it's pretty durable even the thinner foam. When you PlastiDip it, then it becomes a bit more rigid and slightly tougher but not by much. To make a hard plastic shell you can do 6 coats of PVA on the foam and then mix up some RD65 which is liquid plastic. A couple of coats of that and you'll have a hard plastic layer over a foam base. So that's another option for you, go to YouTube and look up X-Robots. He has loads of videos, one demonstrates this process. Sorry cant link it coz I'm on my iPhone.
Drop me a pm if you need any more.

I may put together a product review video this week of different foams to further answer this question.



Jr Member
I couldn't find x-robots, but I think I can do a bit of extra research =] If anything, I'll do glue AND screws. Foam should make it a ton easier to make details rather than form on Bondo, too. Thanks for the help everyone, this forum is quite a great community. Can't wait to get started.


New Member
I'm in the planning stages for a foam armor suit for Grif from the Red vs Blue series, thinking about going with the more hi-def look from season 8, but running into an enigma of sorts:

Should I base the armor and helmet off of a pepakura template, or would it be wiser to go and freehand everything based on photos so that it better matches and fits my unusual frame (at 6 foot 1, 155 lbs, I resemble Jack Skellington more than a Spartan)?


Well-Known Member
You should be able to adjust the scale of the pep to suit your needs.

It's down to your confidence level with the free hand though. I did free hand a lot of my suit and it worked out for the better but I did build up a substantial amount of experience with pep and how to work with foam too.
The key is the understanding of how to work with the material.

As I said 50/50 really if you feel confident then go for it!
Look forward to seeing what you come up with buddy :)


Well-Known Member
well If i were you just start of with something basic. I'm assuming you have pepakura viewer and designer (free) so get one of the files from HERE and then insert it to pep designer and change the scale of it to what you need.

Then just have a go at cutting out the templates and tracing them onto some foam, cutting out and having a play with putting it together. You don't need all the high def parts of some of the pep files (the small niggly bits) for foam but sadly there are no halo files that are designed for foam so you'll need to do some of the work yourself i.e. just get rid of all the small bits so you have all the larger sections of whatever your building.

There are some pep files already modded for foam but I have yet to see some for halo templates. Its usually Ironman files that have ben modded but if you look around you may find some.

Once your comfortable with putting together a templates piece, how it all comes together what shapes etc then you can have a crack at your own, you'll end up making your own templates and then tracing cutting etc.

For more information go to my tutorials which are PART 1 HERE


and my build thread which at some point I discuss how I made my free hand parts

Hope that helps buddy :)


New Member
Thanks Mike, I was kinda sweating that part. I figured I'd end up basically only looking at the pep files while otherwise freehanding things, but I think for some of the more detailed pieces I'll make pep versions so that I have a model to work from.


New Member
If I'm not mistaken, latex paints don't have the structural stability needed. It would work well as a base coat after plasti-dip, but I don't think it would work well as a pure sealer