Chris:
You got a general answer from Moss because frankly no-one here new any real
specifics. Over the weekend at MG2003 I got to attend an excellent
presentation by John Mangles of Hi Tech Collision in St. Louis. He showed
how to remove minor dents in an MGB door, and was a wealth of information.
I took the chance to ask him the same question you have just posed, as you
are not the first to ask. This type of coating is typically found on MGB
bonnets and fenders.
>From his comments: The shipping coating is designed to prevent oxidation
during shipment and storage, and is not a paint primed surface. This means
it is not a suitable surface for top coating. Cut through the coating
surface glaze with wet & dri sandpaper, just the same way you would a top
coated surface. Then use a professional quality self etching primer as a
base coat. By scuffing the surface, the primer has a chance to bond to the
underlying paint/metal, rather than lying on top of the water resistant top
surface.
As stated though, be sure that the self etch primer you are using is
compatible with your finish products.
Anything you can do to prepare the back surfaces of the panels is going to
improve longevity. I've seen some weld through primers, but so far I have
had good luck coating the back of panels with a product called "Extend" by
Permatex. This material takes a lot of heat and does not blister. Coating
the inside of the body sections with Rustoyl or equivalent is going to be
the only real way to get protection inside repaired panels though.
hope this helps.
Kelvin.
> I'm about to do a lot of rust repair on my early B. I wrote to Moss
> asking what kind of primer manufacturers put on replacement body
> panels. The answer I got was very general, to the effect that I
> should make sure it was compatible with the paint I was going to
> use...
>
> The second part of my question was whether I should be
> priming/painting the backsides of parts (like sills and doglegs)
> prior to installation as a rust proofing step. No answer on that
> one. I've seen parts with only primer (rattle-can grey mostly) rust
> through, and many primers aren't meant to be exposed to moisture, so
> I'm concerned.
>
> So my question is, what sort of prep/painting, if any, should be
> done to black-primered replacement sheet metal?
> --
> Chris Attias
> Aptos, CA
> '64 MGB
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