Expanding Foam recommendations?

[jess]

Hey all!

I'm working on creating a 1:1 model of myself to sculpt on. I've been trying different things, and I decided the easiest way to get this underway would be to do duct tape forms of pieces of my body, then fill them up with expanding foam.

So, I finished up my thigh night before last, blocked it off at the knee, then shot it full of "Great Stuff" by Dow, the > 1" kind. I was a little disappointed in the expansion, it seemed to take forever. So, I let it go overnight, and it hadn't expanded much - I was expecting this stuff to explode all over the place.

However, when I picked up the leg, it was still soft in the middle. I pulled on the top of it, and it seems something I did wrong caused the middle to not cure or harden at all, and the hard top popped right off. I stuck it back on, but it's definitely not making any progress.

So, I've got a few questions:

- has anyone worked with this type of stuff? Any recommendations on a brand to use?
- Any ideas about what would prevent the curing? It was a little foggy on my roof when I sprayed it full of stuff, and I definitely used more than necessary, filling it up over 70%. I only left it out there for about 20 minutes before bringing it in to warmer temps. Is it possible that the temperature or using too much caused it to fail?
- Is it possible that the foam that cured on the top prevented oxygen from getting inside, and that's what caused the problem? If so, are there other foams that will react in an oxygen-free environment?
- Is foam the right approach? maybe I should be using something else? I'd like to avoid plaster cause it's such a mess and I'd probably have to strengthen my molds, but maybe that's the direction I should go?

Thanks in advance, if I can work this one out, I hope to have a cool build to share!

 

[lsinnwell]

I've just started using X15 and X30 by TAP Plastics. This foam is also a Polyurethane foam but has to be mixed. It grows to 15 and 30 times it's volume in 30 minutes. AND the instructions warn you about temps that are too cold, too hot or moisture affecting the process. That might be where you went wrong. You can add more polyurethane expanding foam if you measure too little so just keep adding to your mold. I'll bet you're not far off.

 

[booksandcorsets]

You're looking for something more like Foam IT by Smoothon. WAY more expansion. Great Stuff simply won't cut it

 

[klmyhre]

I actually did that exact same thing to make a form for my stormtrooper. I used great stuff. The key is to only add a little at a time, mist it with water then wait a half hour to an hour to add a little more and repeat the whole process until it's full and hardened. I long time ago I filled a torso I made by wrapping saran rap around a frame and I had the same experience as you. I think the fumes keep the foam from expanding in a confined area. Months after doing it you could see liquid inside that never foamed up and was still wet.

 

[RickDTM]

Second the recommendation for Smooth On. Reliable and should work well for this.

 

[Darkproductions]

I make yoshi eggs using flex foam-it III. The foam expands to 15 times its liquid volume so it only takes about half a cup of the chemical to foam up something a little bigger than a football. I will warn you though to have a board ready to back pressure the mold so it will expand thoroughly. I have also heard (but never done it) that people have used "Mountains in minutes" which i assume is the same thing. You can get it at hobby train shops locally.

 

[Scuba Bob]

I use smooth on products exclusively. Their expanding foams are second to none! I highly recommend them. A pint kit of their foam it rigid 3 filled a dive helmet casting that i was doing for a client which was absolutely massive.

 

[Blargh]

Wow! This thread is helpful, glad I stumbled upon it. I'm making a cast resin horn. It will be slush cast so that the horn is mostly hollow, to reduce weight since this will be part of a costume. Then I was going to fill the cavity with expanding foam.

The only thing left is to figure out how to screw or attached the horns to the resin mask base. (I'm aiming for detachable horns, as they extend out quite a bit and having them able to be taken off and put back on with ease is crucial to shipping and storing this. mask.
I'm consulting my local hardware store.

 

[booksandcorsets]

Wow! This thread is helpful, glad I stumbled upon it. I'm making a cast resin horn. It will be slush cast so that the horn is mostly hollow, to reduce weight since this will be part of a costume. Then I was going to fill the cavity with expanding foam.

The only thing left is to figure out how to screw or attached the horns to the resin mask base. (I'm aiming for detachable horns, as they extend out quite a bit and having them able to be taken off and put back on with ease is crucial to shipping and storing this. mask.
I'm consulting my local hardware store.

I'm working on a very similar project (it's been sidelined for a while, though). The outer horn will be in foam and will screw onto the base (which will be backed in foam).

I did this using a threaded rod and a bolt setup before, but this will be much shorter so I'm not sure if the technique will be as secure.

 

[Blargh]

I'm working on a very similar project (it's been sidelined for a while, though). The outer horn will be in foam and will screw onto the base (which will be backed in foam).

I did this using a threaded rod and a bolt setup before, but this will be much shorter so I'm not sure if the technique will be as secure.

Interesting, thank you for sharing! Forgive me , but how does a threaded rod work? I can't seem to find much about it.
Thanks!