Help me make a dent...

How might one do this, in styrene:

http://img3.imageshack.us/img3/3315/carzr5.jpg

I was thinking of just heating it with a candle and pushing it in with a blunt object, but I'm worried I might go too far or make too big a dent, and not be able to return it to normal... :uhoh:

What I would to is to cut in the middle of it (where it has to be) and then bend each side till getting the dent. After that a little putty and sanding session, maybe over a piece of paper glued behind to give it a base if you can't join both sides.

Or even cutting off the parts (especially if they brake while being bent or if plastic is to hard to be bend easily) and remaking the bend with paper or plastic card or something like that you could easily work with to get the bend.

Ideally on a less-complex suface (ie. outer door skin), maybe replace a small section of styrene with metal and after blending it into the surrounding area, hit it with a hammer and small screwdriver or something similar? It'll take more work but the results may be more realistic.

I would make it with a heated metal part that has a shape close to that of the negative of that dent.

Don't use heat! it is extremely difficult to use heat to dent plastic. I'd thin the plastic from the inside, and simply make the dent by pressing on it with the dull side of a hobby knife.

Definitely do not use heat. Don't do it. Plastic deforms in very characteristic ways with heat- and a molten plastic blob looks like nothing else but a molten plastic blob. It certainly does not look like dented metal.

If you want to do this properly, battle damage techniques for model armor are probably the best way to go. This (http://www.amazon.com/Modeling-Tanks-Military-Vehicles-Sheperd/dp/0890240450/ref=sr_1_2?ie=UTF8&s=books&qid=1234920816&sr=1-2) is the best resource I can recommend. But it will likely involve a dremel type tool and some putty. And some patience.