Bondo vs Sand Paper

I'm building a Jango kid helmet and just used a glob of bondo on the top of the helmet....what grit should I be using...is there a rough grit then work to a finer grit?....please help...thanks

Yeah, start with a really rough paper 1st, then slowly work your way down. I usually start with about 180, then go to 320, and sometimes a few more inbetween, and finally end up with 800 grit wet sandpaper. Just go slow, and make sure that by the time you get close to your actual prop surface (helmet in this case), you are at least using 320. If you use a really rough sandpaper too long, you will have all kinds of scratches in yout helmet that you will have to go through and re-bondo/sand.