David,
I am no paint expert but if you approach the problem with some thought I
think the Bondo to bare metal works. Sometimes the craftsmen who are not
engineers just follow methods they have learnt by rote. Similar to "you
cannot use copper lines for brakes", Just consider that if the bondo was
metal you would not put primer between! Now the bondo is some strange
stuff that will not cause rust between them UNLESS you get it wet. If the
metal got wet WITHOUT the bondo it would also rust! So the trick is to
stop water getting to the metal AND to the metal with bondo. So you prime
the whole damn area to seal off the bondo and adjacent metal. If you get
pimples it is because the bondo/metal contact was contaminated or damp
BEFORE it was sealed with primer. And remember primer is not too good as a
sealer as it made as a base for paint - not a sealer!
At 10:26 AM 7/18/2003 -0700, David Breneman wrote:
>Blair J. Weiss SEZ -
>
> > Bondo goes over bare metal, seam sealer goes over primer.
>
>The fellow doing the body work on my MGA tells me emphatically
>that you always apply body filler (don't know if it's Bondo
>brand he's using) over primer, then apply more primer over the
>filler. This is to prevent moisture from getting between the
>filler and the metal (since the filler is hygroscopic), causing
>rust and separation of the filler from the metal. This
>condition usually shows itself as little "pimples" under the
>paint which, if impacted, will cause a chunk of the filler
>underneath to break free from the body and leave a big hole in
>the paint.
>
>--
>David Breneman | "I don't care to belong to a club
>Distributed Systems S/W Analyst | that accepts people like me
>Airborne Express, Inc. | as members."
>david.breneman@airborne.com | - Groucho Marx
Regards
Barrie
Barrie Robinson
barrier@bconnex.net
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