View Full Version : Bodywork Question

08-01-2006, 09:57 AM
I have read everyting I can get my hands on about stripping and
painting a car. My question concerns the sequence of same.
I have read that where body filler is used for repairs, it should be applied to bare metal, and a etching primer on the good metal. Then a build primer, block sanding, then sealer and paint applied. I have also seen recommended that you apply the etching primer over the entire bare metal panel, and then the body work (filler) is done on top of that. Then the build primer etc. is applied.
Does anyone know which if correct, or better?


08-01-2006, 10:30 AM
In my experience, the body filler works best if applied over the bare metal that has been fresh ground using a 36 grit disc on a grinder. That gives the best adhesion for the filler. Then proceed with the next step according to mfg. recommendations printed on the label. Do not let the bare metal sit exposed to the elements. A film of rust you can't see can form on the metal,:( causing the body filler not to adhere and you won't see this for a year or two. Then the filler starts turnimg loose, cracking, then falling off...:(. At that point, you WILL be able to see the rust! It's cheaper and easier to do it right the first time.;) Hope this helps.

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08-01-2006, 11:09 AM
When painting structural steel, exposure after blasting is limited to max 4 hours. Any longer, and the steel has to be re-blasted.

08-01-2006, 08:02 PM
After getting the metal as straight as I can --
On bare metal I apply an epoxy primer like ppg DP40 and then put any filler on top of that. Years ago you were advised to apply the filler straight to bare metal, that has now changed. Applying it over the top of the epoxy primer gives better adhesion and protects the metal better as filler is somewhat porous.
I then shoot a blocking primer product usually PPG K36 or some such and guide kote with black for block work.
This forum is excellent for bodywork and painting related stuff ---

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08-01-2006, 08:43 PM
If you are going to fill rust holes make sure you use a waterproof bondo for the initial fill followed by the cheaper easier sanding stuff. Using the epoxy primer first is correct though.

08-01-2006, 10:19 PM
I was surprised to find that the principal ingredient of cheap bodyfiller is talc. Of course, it sucks water to bare metal just like a baby'd butt. Rust happens, and the filler falls off, and worse damage is left behind.

Use waterproof bodyfiller. Some auto factories even use the metalised waterproof bodyfiller for smoothing seams at the factory.

Paul R

08-02-2006, 07:33 AM
Thanks for the advice. You made good points that I didn't
even think about; as a matter of fact none of the material I
have read even mentioned some of this. I have been stripping
panels over several months, as time permits, but I was never
in a hurry to cover the bare metal. Now I'll go back and
do some re-stripping and regrinding to get it right. Thanks again.

08-02-2006, 09:58 AM
An EXCELLENT autobody resource is at www.autobody101.com . The forums are excellent

63 Lark 2dr Sedan