On 22 Oct 2004 19:59:35 -0700, (c hinds) wrote:

What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

A couple examples that I am aware of, you can use them to assemble
fuel tanks and once the seams are welded up you then weld over the
rivets to seal them up, which is possible because the soft rivets are
weldable 1100 alloy and the hard rivets are not weldable. I built a
pair of fuel tanks this way and it worked but next time I am going to
just put sheet metal screws in the holes and once the tank is welded
together pull the screws and weld up the holes. For whatever reason,
all but one of the leaks I found and had to re weld in my tanks were
at the rivet locations.

The other application which I am aware of pertains to the aileron
balance weights in some Cessna aircraft. A hard AD rivet shouldn't be
used because it is hard enough that as it is driven, the expansion of
the rivet will just deform (and expand) the lead balance weight.
Originally a different rivet that I believe was alloyed with magnesium
was used, but this lead to dissimilar metal corrosion so the current
method involves using a slightly bigger "A" soft rivet instead. It
has to be bigger to be strong enough, and because it is soft it won't
deform the weights when driven.

If you are going to have "A" rivets around for obvious reasons you
need to make absolutely certain that none of them migrate into your
"AD" rivet stocks, because they are much weaker.


================================================== ==
Del Rawlins--
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
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