i want to do a foam carving of a car for a school project, but i haven't done one before. Is there special foam and can you leave the foam when its done or are you supposed to cover it with clay. what are you ment to use to actually carve the foam, just sandpaper and a knife? :S

yes, good question.
I'll have to do the same for school. where do you buy the foam and how to work with it?
manolo

Not sure what it is called but the foam most people use is a blue foam, which can be cut with a saw/knife and sanded to give a relatively fine/smooth finish.

You don't need to cover it in clay, but it is also used as support for clay models.

Another option could be quick sketch models from card or sponge (sponge has the benefit that it can be cut and shaped with scissors for a more rounded form).

If you can get blue foam that would be the best thing for a final model.

Bacon means styrofoam! You can use rasps which are good for shaping the general form of the model once you cut it with a saw

I've got loads of that stuff; its in the carpet of my old house, forever.

You can buy styrofoam from a builders merchant, it is fairly expensive though, about £60 for 8' by 4' by 100mm

If you're not gonna cover the foam and clay and want a really smooth and finished looking model, I would suggest you get industrial 10 lb or 20 lb foam. You can use a band saw (if available) for rough cuts and rasps to do the major carvings and then sand it down to a fine finish. 20 lb will give you a finer finish and details then 10 lb but will also take more effort to carve/sand down.