Fuel tank rivets--mandrel problem
Posted: Sun Feb 19, 2012 11:38 am
I riveted my bottom fuel tank skin on yesterday using RV-6403 tank rivets.
During this (messy <grin>) process, I noticed that perhaps as many as 30% of
the mandrels did not break off. I adjusted my pneumatic rivet gun as tight
as it would go. I also ground down the rivet tip on the gun as far as
practical. I even tried a manual puller with about the same % problem
results.
I held up a RV-6403 rivet to a standard RV-1410 rivet. The mandrel on the
RV-6403 rivet was 1/8" or maybe 5/32" shorter than the mandrel on the
RV-1410's. So therein lies the problem (or so it seems).
When I first saw this mandrel issue happening, I got a bunch of scrap metal
and put some 6403 rivets in. Didn't appear to matter whether I was going
thru a total of .060 or as much as .080 total thickness-I still had maybe
30% of the mandrels fail to properly break off. The good news is, on the
tests, the rivet tails appeared to be the same regardless of whether the
mandrel broke off or not. In other words, I'm quite confident that the
rivets are Ok as installed on the tank skin.
Did I get a bad batch of rivets? I don't know. What a pain, though, to
have to go back and [carefully] use a cutting wheel to take off those
mandrels that didn't properly break off.
I posted pictures of the problem in area 106 S/M wings
Ted
Moose N384JP
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During this (messy <grin>) process, I noticed that perhaps as many as 30% of
the mandrels did not break off. I adjusted my pneumatic rivet gun as tight
as it would go. I also ground down the rivet tip on the gun as far as
practical. I even tried a manual puller with about the same % problem
results.
I held up a RV-6403 rivet to a standard RV-1410 rivet. The mandrel on the
RV-6403 rivet was 1/8" or maybe 5/32" shorter than the mandrel on the
RV-1410's. So therein lies the problem (or so it seems).
When I first saw this mandrel issue happening, I got a bunch of scrap metal
and put some 6403 rivets in. Didn't appear to matter whether I was going
thru a total of .060 or as much as .080 total thickness-I still had maybe
30% of the mandrels fail to properly break off. The good news is, on the
tests, the rivet tails appeared to be the same regardless of whether the
mandrel broke off or not. In other words, I'm quite confident that the
rivets are Ok as installed on the tank skin.
Did I get a bad batch of rivets? I don't know. What a pain, though, to
have to go back and [carefully] use a cutting wheel to take off those
mandrels that didn't properly break off.
I posted pictures of the problem in area 106 S/M wings
Ted
Moose N384JP
-----------------------------------------------------------------
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username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
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