Expanding Foam body sculpting

[aerohead]

Originally Posted by California98Civic

Gonna be revealing more of what I don't know here...

By "pink board" we mean something like this? INSULPINK Foam Insulation Board - Residential Insulation - Owens Corning



Will the resin dissolve the styrene even if the styrene is encased in polyurethane foam first?

You ought to be good to go if the resin can't get to the styro,either pink Formular,or garden variety 'blue board.'

[Varn]

Pink board or blue boad is the stuff used as foam insulation. You can get it from 1/4" fan fold to several inches thick. It is used for a lot of projects in the HPV arena that I have been a part of.

[Varn]

You should use epoxy resin to prevent melting. It is stronger as well. Works great with all composites.

[deejaaa]

Originally Posted by California98Civic

Okay, I have polyurethane expanding foam in spray-cans (Dow's "great stuff" ............

i have heard nothing good about using this stuff in large areas. the center will remain liquid until exposed to air, usually when not wanted. it then expands, losing all shape given.
i would stick with 2 part mix and use it in small batches.

[sendler]

Originally Posted by deejaaa

the center will remain liquid until exposed to air

Good to know.

[Otto]

Originally Posted by California98Civic

Gonna be revealing more of what I don't know here...

By "pink board" we mean something like this? INSULPINK Foam Insulation Board - Residential Insulation - Owens Corning



Will the resin dissolve the styrene even if the styrene is encased in polyurethane foam first?

Not if the polyester resin does not contact the polystyrene. There are barrier or prophylactic methods to protect polystyrene, so google for foam sculpting websites for hobbyists and artists. Could be, just use Gorilla Glue (polyurethane glue) to bond the two types of foam together.

Or, even though epoxy is more expensive than polyester resin, you're not using that much of it, so cost difference is insignificant. Or, maybe there's an offset in cost of polystyrene vs. polyurethane foams, such that the bottom line cost difference for the project is no big deal.

I don't know where vinylester resin fits in all this discussion about chemical compatibility with polystyrene or polyurethane foams, but am reasonably certain that at typical homebuilt curing temperatures, vinylester resin is essentially as strong as epoxy, but much less expensive. Could be, vinylester resin is a good cost/benefit compromise for use with both types of foams.

[Smurf]

Originally Posted by deejaaa

i have heard nothing good about using this stuff in large areas. the center will remain liquid until exposed to air, usually when not wanted. it then expands, losing all shape given.
i would stick with 2 part mix and use it in small batches.

However, much of this effect can be minimized by not pouring large amounts at once, correct? For a grill block, let's say, you could fill the "deep" part about two inches, let it cure some, then add another layer to build up your depth? Will GreatFoam glue to itself to form a solid piece, or would it break off in the layers?

I think many of us have big ideas for GreatStuff but are intimidated by all these 'rules'

[Varn]

I made the fairing by using 1/4" foam and using 2 part foam as adhesive to hold the various parts together. To get the 3 d shape near the front of the fairing I cut pie shaped wedges and pulled them together while gluing behind them with the foam. Just gave those areas a bit of shaping with 36 grit sand paper.

When I had achieved the shape that I wanted, I covered it with a single layer of carbon fiber and painted on epoxy.

Although aesthetically pleasing it was too long and didn't work any better than the little fairing I had prior.

The shape was determined by the flex in the material.

My mini van nose cover and wheel spats were basically the result of fabric stretched over areas and then composite was laid up over the sails created. Much faster than carving and sanding. If I were to do it again I would clear window film plastic and build the reinforcement on that. If you are interested could post them again.

[Xist]

Originally Posted by Varn

Pink board or blue boad is the stuff used as foam insulation. You can get it from 1/4" fan fold to several inches thick. It is used for a lot of projects in the HPV arena that I have been a part of.

I have mentioned this a few times, I needed to special-order it from Lowes:

Shop Pactiv Extruded Polystyrene Foam Board Insulation (Common: .25-in x 4-ft x 50-ft; Actual: .25-in x 4-ft x 50-ft) at Lowes.com
Owens Corning FOAMULAR Fanfold R1 1/4 in. x 4 ft. x 50 ft.-10UM at The Home Depot
http://www.menards.com/main/building...024-c-5778.htm

I do not know that Home Depot still carries it, nor am I positive Menard's is a real store. The product that Menard's sells says it has foil on one side. I do not know about the magical mystical mysterious Home Depot one, but as I had read on-line, the product from Lowe's has a layer of the thinnest plastic that I have ever seen, with a series of perforations, and when you try to remove the plastic, the perforations cause it to shred. I tried to remove the plastic on one sheet, attempting to roll it around a dowel as suggested, and I could not get it to work.

[deejaaa]

Originally Posted by Varn

............My mini van nose cover and wheel spats were basically the result of fabric stretched over areas and then composite was laid up over the sails created. Much faster than carving and sanding. If I were to do it again I would clear window film plastic and build the reinforcement on that. If you are interested could post them again.

i would like to see it.