I am starting to prep my truck to paint. I am going to paint it "Hot Rod Black" and apply a camo strip on the bottom with camo 4x4 emblems on it. I have a few holes on top of the bed rail that was holding my toolbox down that needs to be filled.

My question is how big of a hole can bondo safely and effectively fill without having to splice in another piece of metal or weld in to fill?

Does the bondo have to be applied over bare metal or can it go over primer?

Thanks

Tim

 

Really shouldn't fill holes with any filler. Holes the size of a pencil eraser can be welded shut using a copper backing plate if at all possible. Filler should go on bare metal. Bondo is a brand name, a cheap brand name. All fillers shrink, just some more than others. Filling holes with it will come back to haunt you in a short time.

 

Everything he said.

Any filler should be used sparingly. My truck has bondo (plastic body filler) all along the top of the bedrails. It sucks. Do as much metal repair as you are able, then if you must use a filler, use it sparingly. Give it plenty of time to cure so that all shrinkage occurs before topcoating. Finish off with a glazing putty prior to topcoating.