Soap Box Derby - Body filler question
This isn't a Jeep question, but it does deal with body filler so I'm hoping I'm in the right section...
My son and I are building a soap box derby car and the body is going to be masonite hardboard (brown colored 1/4", slick on one side, rougher on the other). We're looking for that smooth look so I want to put body filler over the screw holes so that it ends up being smooth and then we'll paint it.
My questions are: with body filler hold to the slick side of the masonite hardboard? Will I need to scuff it? Will the body filler eventually crack on me with all the bumps (small wheels) and the fact that the body will probably not be 100% solid (the frame will be all wood/2x4's, so I'm guessing it'll have some play, I'm hoping for none). Any tips on body filler for this application would be great.
CJ7 86, 258, BDS 4", 33's, currently in a frame off resto.