Well, your local hardware store ought to have a few different kinds of wood filler. The wood filler is applied with a putty knife (or any type of spreading utensil) and when it dries, it'll be nice and hard. (here's an example from stewmac)



Then, you'll want to get yourself some paint and some sandpaper (according to my link below, you'll need 220 grit to prepare the wood surface, and 800 grit wet sanding sandpaper for the final finish) from that same store or a paint store.

And, I don't see why a car paint sprayer wouldn't work; actually, it'd probably do just fine, since car finishes need very even coats. I'd ask at the paint shop/hardware store just to be sure, though.



Wicked... I just found a step-by-step description of the procedure from www.stewmac.com:

http://www.stewmac.com/freeinfo/I-NITROCELLULOSE.html

The description here is the more professional way than my ghetto way.