Expanding Foam/insulating foam - don'ts

Kissker · Jul 11, 2010

Expanding Foam/insulating foam - error

So, being me I thought "hmm.. I wonder if I could use expanding foam (the insulating foam you can get at Wal-Mart cheap) to help hold the shape of helmets and stuff"

Well the idea is sound, but application is a pain. I wanted to find a way to avoid 'glassin the inside of helmets/armor, mainly to reinforce and support the piece and take a cast from it.

Instead.. I found myself making messes. lol.

Here is what I learned, it has possibilities, but I am giving up after the second helmet failure.

First thing I learned that you may not realize: Expanding foam expands of course, but then SHRINKS. This expansion sticks it to everything as hoped, providing maximum holding power.. but because it stuck to the insides and then SHRUNK, deformities were everywhere, and daily the helmet got worse, and worse. Some pictures will help I am sure.

You COULD use expanding foam to fill a helmet for this purpose (or for non-wear, display uses, like making a statue, just jam some PVC pipe in it to hold it up, etc) However you would need to line the helmet first.

I find aluminum foil (heavy duty) and masking tape works wonders, not only can you put several layers in to thicken it, you can then bend it and it will help hold the paper shape you desire! (one bright side from this mess) just layer it inside, or fold strips and layer to provide more support in specific areas.

When using the foam - expect the can to seal shut - but - do NOT just "use more" because the can will be wasted. Instead plan ahead and do several pieces at once. you will only be able to put a few "lines" of foam in at at time - and then wait until they FULLY HARDEN before adding more. This will be very time consuming. My first attempts just treated the Helmet like a 'void' to fill like the foam is designed to - filling just less then 1/2 way and letting it expand. My second attempt only did a few lines - but all over the helmet - and the expansion was still a disaster. A third attempt was thought out - but never finished - line it with foil - and only put 2 lines in the start of it in the "top" of the helmet, let them fully cure, then add more slowly, taking many days (and many cans) to fill the helmet.

Needless to say this isn't very practical and a proper technique will need to be developed. My suggestion from this is to STAY AWAY from the foam.

This is due to the cost of cans + time to cure + more detailed operation VS other methods, even other foam methods.

Breaking it down, it would probably take 4 days and 4 cans of foam to "fill" 1 helmet (or more likely, 4+ helmets at the same time) Applying a thin line of foam to each and letting it fully set up before adding more lines to fill in more gaps. Considering the foam being about $3 a can, foil about $2 and tape about $2 that's about $16 to do this. Sure, not bad, but 4 days to do it as well, and very wasteful of foam. (a full can would fill up a helmet on it's own for volume) You would have to set up your whole suit (or probably 10 helmets) to use up 1 can a day just putting a couple of lines in them at a time. You can buy liquid expanding foam and use a better measuring method for expansion for probably $20 in most areas, plus shipping, and it comes in Part A and Part B so you don't "waste" it all in 1 go like the cans.

So yes, the foam has potential uses, but only if you were say making 10 statues of the armor to cast molds off of, or just to have some sweet lawn decorations... I can think of nothing better then a bunch of Halo 3 Spartans (in various armors and positions) statue on my lawn fighting one another, ducking behind a bush reloading, standing over a bosh firing, sneaking up with a grav hammer.. etc. It would surely be an epic lawn decoration.

Now some pictures of my mess.

Projects Ruined:
Iron Man MK VI
Iron Man (basic sizer)
It starts with the completed Pep, and then slowly gets worse and worse as the days went on.

Gixxer · Jul 14, 2010

i had bad experience with foam as well ..some of my marine armor actually shrunk after a few days completed it. It was fine the day after and survived a con. But the foam inside my CQB helm doest shrink .. i put two layer of resin on top of the foam and its fine even after a month ..

Expanding Foam/insulating foam - don'ts

Kissker

Member

Gixxer

Jr Member

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