Foam cutting tips?

[Anonymous]

I have a few questions that hopefully someone here can help with.

I have seen people cut white, pink, and blue insulation foam with Hot Wire cutters. But I am curious if the same methods can be used for cutting the expanding insulation foam that come in cans. One of the brands is called "Great Stuff". You spray it from the can and it expands. When it drys it looks like blobs of yellow lava. I have noticed that it has a bit of a different consistancy from the other foam. It has a more rigid shell. Would a wire cutter work on this or not.

Another question is related. I have several places that I want to have high hills and valleys in foam. Should I glue these areas together then cut with a hot wire or cut then carve. I prefer the first option because it would seem more naturalistic but I am worried about the effects (messing up the cutter, ...etc.) of cutting through the glue.

My last question is similar but more on based on technique. I want to make four scenes that are exactly the same. I mean the same topographey to show the same location over time. I would like to do this in foam. Any ideas on a simple trick to make four exact copies?

Thanks for the help.

[selector]

I can't help with the first question, because I don't know what the material is that comes out of the can. Chances are that you will be able to use the hot cutter, but in any case, the fumes are toxic, so beware.

You should eyeball the rough shape of successive layers and cut them first, and then do the finer shaping once it is glued into place, to answer your second question.

As for your third, I suggest you figure out the basic shape first, then cut the rough layers. Stack them without glueing to see how they look, alter as necessary, and then make a copy of each layer. Merely place each layer over a fresh sheet of foam, and ink around the edge for a cutting mark. If you are using a spray, no idea how to duplicate the shape, unnless you spray into prefabricated molds of chicken wire lined with tin foil. You can always re-line the chicken wire with foil, but hopefully your wire won't change shape too much.

Good luck.

[rrinker]

A good serrated knife also works well to cut the foam. Some people have reported good results using an electric knife - but go buy your own, do NOT take the one from the kitchen. A used cheapy from a yard sale would be a good way to obtain one.

--Randy

[Anonymous]

Thanks for the help and good advice.

Someone in another area gave me some good advice on the last problem. To make multiple copies of the same shape to stack the foam so it is vertical like cards in a card catalog at a library and make the shape I want. His advice was to use thinner sheets of foam like 1/2 inch to get closer to a smooth shape. Then before I glue this together, separate the layers and copy them by tracing and cutting the layers of the other versions. The final smoothing of the shapes would still have to be done individually. This is the best solution so far.

Thank you for the advice.