Gunmaking, Any suggestions before I get started?

Hey everybody, I'll have to start the traditional topics with the most "how-to" questions but I'll be turning my little project into a tutorial and be submitting it for this website!
Prop making is SO not my thing!! I tried to make a few things but they usually blow up in my face... so I'd like some input and suggestions for gun making techniques...

What do you feel might be the best material to make a gun out of?
Is it better to make it in parts and attach them together? How?
What is best to paint finish it?

I'm making an Aya Brea costume from Parasite Eve and, although I do have toy guns, I'd like to try making one myself a little more like the actual gun used. Plus I need to overcome this prop-making fear ^^;;


Thanks everyone!!

Well, the right material depends a lot on what you have handy at home, how much effort you'd like to put into it, and how detailed you'd like it to be.

General note on detail - guns have a lot of little things that make shaping a pain. Consider shading in some of the details with paint instead of trying to shape/carve them.

Painting - well, you can go for the metalic acrylics, mixed with a solid colour (like black) to give some shimmer to it) Another choice for good metal-looking paints can be found in the automotive section of a hardware store - they've got paints meant for car finishes, so the gloss black (or chrome) look would do well for flashy guns. The spray paint is also good for not filling in detailed grooves if you're careful, but be careful using it on styrofoam, since it'll dissolve your work unless you seal it with gesso (I've been told a diluted mix of white glue works too).

Possible materials...

Wood
Toughest of the options to shape properly (i.e. a good coping saw, a few carving tools, lots of files and sandpaper. On the flip side, easy to finish and paint, and will handle details well. You can use putty to fix mistakes too. The tricky part would be carving out the gun in the first place - consider doing it in pieces to avoid frustration if one part is wrong. Remember to use softwood - chipboard will likely, well, chip easily, while hardwood would make carving an exercise in frustration.

Polyurethene/Polystyrene foam
Easier to shape than wood, but still carved. Be careful, because some paints eat polystyrene (polyurethene is a little more resistant) so you have to seal it in gesso or white glue first. Get a block from a craft store (or white glue layered sheets together) and carve it down. Warm your cutting tool for an easier cut, just not so hot you get hit with fumes. Light, and since the gun is small, you're not going to have as many worries about it snapping it in two, unlike a larger prop.

Clay
Using something like sculpey makes sense - the only issues would be shrinking and the thickness of the clay. It'll be a bit heavy, and you may need a second try to make sure it dries to a shape you like. It should paint up just fine, and unlike the carved approaches, you can fix your mistakes. Getting one side of a gun shaped the way you want without undoing the other side, however, could be a trick. I've never worked in clay myself, so likely more capable folks can give good answers to that.

A few suggestions...

or get a base gun and work on top of that^_^

There are also Pepakura Guns out there on the web like the weapons found on http://halocostuming.wikia.com/wiki/Pepakura_File_Index

I also make guns out of pep and fiberglass the outsides to make them props I even have a couple working ones.