On Mon, 12 Mar 2018 16:17:18 +0100, Emanuel Berg
wrote:

AMuzi wrote:

In a closed figure, overall
expansion/contraction is a real problem.

When you see guys do aluminium tubes with MIG
or TIG one gets the impression that the filler
metal and gas/weld area sure is warm enough but
for the whole structure to disalign from this
isn't something I instantly think of...

Firstly aluminum distorts more then steel at any given temperature.
But as I said previously, a bicycle is two triangles and very small
distortion of any part of a triangle will have large effects.




I suppose the bicycle frame fixtures have
clamps to allow just the right minimal play so
that tubes don't suffer too much stress/strain
while at the same time still remain in their
right places with enough stability?
--
Cheers,

John B.