As our older son came home to visit for the weekend from the Virgin Islands I was limited to garage time but I did get a chance to experiment on working with foam and the exterior foam hardner. I have to say it looks like this is going to be a great medium to fabricate parts for robots.
It's not as easy as I thought but foam is forgiving and sand able. So I made a few extra heads until I finally perfected my technique (and ran out of Styrofoam). The goop that covers the styrofoam mixes up easily with water and makes a goop that you slop on over the foam. It's pretty hard when it dries and can be sanded. But like Bondo, it is a challenge to get smooth.
I also resurrected my home made foam cutter by buying a decent power supply. After getting the power supply in the mail today, I hooked it up and immediately had a super heavy duty large foam cutter at my disposal. And it worked well with the guitar strings. That foam cutter will allow me to carve very large blocks of foam as opposed to the little measley cutters I bought at the hobby shop. This is just perfect for cutting out a Rosie the Robot from the Jetsons body. Another noteworthy fact with foam is you can make large blocks by hot gluing the foam together. Works perfect !
The weight of these new heads is just a fraction of what my wooden heads weighed in at. So now I'm back to the challenge of mounting the heads to the motors on the robots .... but at least I don't have to fight all that weight.