Soap Box Derby - Body filler question -
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Go Back > General Technical Discussions > Paint and Body > Soap Box Derby - Body filler question

The Original 3/8" Ruffstuff Diff Cover!Ruffstuff Axle Simple Swap Kit!The Ruffstuff NOT Universal 4 Link Kit!

Unread 04-09-2013, 07:26 PM   #1
Registered User
1986 CJ7 
Join Date: Sep 2008
Location: New York, NY
Posts: 90
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.

86cj7pete622 is offline   Reply With Quote Quick reply to this message
Unread 04-09-2013, 09:56 PM   #2
Registered User
1986 CJ7 
Join Date: Feb 2013
Location: Iuka, Mississippi
Posts: 72
U might have already got ur mat. But if u have not i would go with 1/2 or 3/4 BC plywood . Then get a kreg kit and use pocket screws and wood glue. It's easy to use and makes a super strong joint and screw holes will be on the inside.
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Unread 04-10-2013, 08:16 AM   #3
Web Wheeler
1974 CJ5 
Join Date: Jan 2005
Location: Santa Maria
Posts: 1,616
Bondo does work on wood with the smooth surface of masonite you'd probably need to scuff it up for it to hold best. Personally I would go with plywood like BDP72 suggested. If you take your time with sanding you can get it incredibly smooth.
thantos858 is offline   Reply With Quote Quick reply to this message

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