> I have a similar question relating to my "new" BMH MGB Body
> Shell which
> is still in it's crate and has been waiting for me in the
> garage since 1991.
>
> My understanding was that these new body shells were dipped in modern
> primers during manufacturing. On close inspection it appears
> there are
> two primers on this shell. A darker gray which appears to be
> "thinner"
> and can only been seen inside the shell members, where it was hard to
> reach with spray, and an outer lighter gray, and thicker,
> primer which
> appears to have been sprayed over the darker coat.
>
> I have two questions:
>
> 1. Can these two primers be used as a base coat after proper
> sanding and
> surface prep?
To my knowledge. Yes. When they were building up complete cars,
they never stripped all the paint off.
>
> 2. What if anything was done to the inner sills during manufacturing?
> After or before welding were these protected in any way?
> Would the dip
> primer reach them, or are they unprotected and have been rusting away
> while sitting in the crate these 12 years?
This is a very good question. Kai pointed out that he knew of a BMH
shell rebuild that started to rust after only a few years. This indicates
that the rust proofing is not dependable.
I would strongly suggest going in after the car is painted and
protecting the interior of the rockers with a spray on coating. You could
do this now, but you have to make very sure all the goo gets out before you
spray the car. Better to spray the car first, then goo.
I think you will find the thin primer is from the dip tank. Then
when the outer body panels were assembled, the assembly roughness and
transport dings were filled, then the whole body shell coated in primer
surfacer. At this point the shell should really be sanded down by someone
that knows what they are doing, so any metal-primer problems get sorted out.
This does not mean going down all the way to metal, but down far enough so
the new etch prime coat can adhere well.
I would strongly suggest taking this up with a good body man who
knows their materials. That is the only way to get a reliable answer.
K.
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