Thanks to everyone for their advice on the best way to patch my MGA frame.
I solicited advice from a couple places other than this mailing list and the
opinions are pretty clear...
"4 out of 5 welder's surveys recommended butt welding in patches
for their friends who restore old English heaps"
Repairing the chassis this way has been my gut feeling from the onset. I spent
$400 to have the chassis dipped, so I now want to do it correctly both from a
structural and cosmetic standpoint. I will be doing the straight butt welds
and
not using lap joint flanges. I have thought long and hard (for about a month)
about the best way to hold the patch in place while tack welding it. I am
going
to attempt to use magnets to hold the patch flush with the existing metal. If I
cannot get big enough magnets, I'll tack weld some metal strips to the patch so
I can use clamps. I'll just grind away thos tack welds when the patch is held
in
place. I have my own MIG welder and have become pretty good with it. I'm
confident that I can do this job. If, by some chance I screw it up, I can
always
have a pro cut out my work and do it better. Its only money.
Before having the frame dipped I had already talked to professional restorers
and decided on a method to coat the inside of the frame box sections. To my
knowledge, they weren't coated when new, so leaving them alone wouldn't be the
worst thing on earth. After spending this money, however, I will ensure that
they are at least coated with etch primer, then (after the outside of the frame
is painted) waxoyled.
The outside of the frame will be painted with a three pack etch primer (paint,
reducer, hardener) followed by black urethane three pack paint used for marine
applications. The amount of gloss should be consistent with a car frame and
this thing should never rust again. The paint is $300, but this is a one shot
deal; I don't intend on having this car disassembled to this point again. I'll
be busy driving it. I have the proper saftey equipment for this type of paint.
Its not a fresh air system, but the cartridges for my respirator are rated for
this type of paint.
Someone mentioned brazing in the string. As, I believe, Chris Ball pointed out,
brazing doesn't seem like a good alternative because stresses caused by rough
terraine and my big old butt in the seat could cause cracks in the joint and
would offer little in the way of strength.
Cheers,
-Al Legerlotz
1957 MGA Roadster peices.
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