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Seam Welding
Most performance enthusiasts have heard of seam
welding but few know what it actually is or how it's properly done. most have
questions like:
- When seam welding does the whole seam get
done?
- Is it a good way of increasing body strength?
- What seams to weld?
You have to be careful seam welding so as not to
twist everything out of shape. This is one of the reasons you stitch an inch,
leave two. Some seams don't need it, and you would be wasting effort to do them.
You also don't want to start in one place and go straight along one seam.... you
have to move around to other places around the body, so as not to concentrate
too much heat all in one place....
You also have to make sure the seam is clean... no paint or underseal, or you
will get porous welds that contribute little if anything to the stiffness.
It certainly can increase the torsional stiffness of a chassis, combined with
some creative triangulations in high stress points (don't ask me where they are
on different cars, never worked on everything!!) can really make quite a
difference.
Triangulating where chassis members join the firewall/bulkhead usually pays good
dividends in strength gained against time spent and added weight.
Talk to other racers and ask them where the main chassis weaknesses are for your
car.
Look at some smashed cars and see where they buckled like they are meant to....
and leave those areas alone. Otherwise you will diminish the effect of any
crumple zones, and in a heavy impact more of the loads will be transferred where
you (probably) don't want them to...
You will feel a big difference in how much movement there was in the door
openings before and after seam welding the car, and I think most of this change
came from the reinforcing and seam welding at the firewall. Crumple zones aside,
I have a hunch that all the panels/sections that go across the car (on an
enclosed roof car) contribute more to torsional strength than those that run
along the car - like the firewall and where it joins to the body, or any box
sections spanning left to right of the rear suspension, and where they join to
the body at either side.
I also have a hunch that to improve the lengthwise torsional strength of the
car, there's a limited amount you can really do besides put in a roll cage - not
ideal for a road car...
You'll end up with a big improvement on standard even without a rollcage IMHO,
because the suspension at each end by itself will hold its geometry better under
hard cornering.
This article was written with info from
turbo124
Information provided by the following members:
- th130
- fiatfactory
- snoozinFearits
- SteveNZ
- Fraud
- BT
- 1290cc-128-coupe
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