Chiming in.
I took the Eclectic Motorworks MGB sheet metal class over the weekend, so feel
relatively educated enough to chime in.
One of the points stressed during the class is that welding always causes metal
to want to move.
The emphasis of the class was on "sneaking up" on panel fit, so that constant
checking is made to ensure that each repair gets the shell closer to an
accurate door fit.
Welding in support beams prevents the shell from moving under the welding
stresses until the beam is finally cutout, at which time the built up stresses
have their evil ways and can twist the shell out of true.
When the shell was originally assembled rocker panel assemblies were jigged and
welded to the support platform. The panel assemblies had full strength when
they were installed and a jig could be used to ensure location. During the
rust repair process, each of the sill components is added one piece at a time
and as each piece is added the sill becomes stronger but the welding induces
twist and warp. Supporting the body of the car at the suspension points and
continually checking door fit ensures that as the sill is strengthened with new
sheet metal, movement can be taken into account and the correct gaps are
maintained.
It was pretty amazing to see this done on a 64 chassis that was way beyond
anything I would expect to restore.
Kelvin Dodd
________________________________________
From: TJ Tryon, Jr. [mailto:tjt@insightbb.com]
Sent: Saturday, March 19, 2005 4:15 PM
To: 'MG List'; MG-MGB@yahoogroups.com
Subject: [MG-MGB] Sills
What a mess, unfortunatly, once I got the fenders off, it seems that the tin
worm ate quite a bit more sill/rocker metal since last summer. Strange
thing, I tried to keep things dry and clean, and it was parked inside all
winter. Pictures can be found at:
http://tj.lhc-group.com/gallery/view.php?gallery_id=20
Next step is to weld some support beams in the door jam and start to drill
spot welds.
Any advice prior to getting started?
TJ
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