fuel tank rivet size

[billdianne]

I'm just starting to rivet the fuel tanks (rv8). The rivet size callout is for an426ad3-3.5 but they look a little short. What is everybody's experience been
with this. Has anybody gone to a -4 or is the-3.5 the rivet of choice?

Thanks,
Bill

[David Johnson]

Originally Posted by billdianne

I'm just starting to rivet the fuel tanks (rv8). The rivet size callout is for an426ad3-3.5 but they look a little short. What is everybody's experience been
with this. Has anybody gone to a -4 or is the-3.5 the rivet of choice?

Thanks,
Bill

Did you use tank dies to dimple the skin and ribs? If not, and you didn't give the C-frame some really good whacks for each dimple, your rivets may stand just a scosche proud of the skin and make them seem too short on the inside.

I did not use tank dies, but whacked the heck out of the c-frame for each dimple. The 3.5 rivets worked fine.

Dave

[Guy Prevost]

3.5's looked a little short to me too. However, I talked to a local builder that had to rebuild his tanks because he used 4's and then clenched them over while shooting them. He couldn't tell at first because of all of the ProSeal making them hard to inspect.

I used 3.5's on mine and they worked great. The shop heads on some are a tiny bit short, but 90+% of them are perfect. I did use fuel tank dimple dies.

YMMV,
Guy

[Rick6a]

Originally Posted by billdianne

......The rivet size callout is for an426ad3-3.5 but they look a little short. ......Has anybody gone to a -4 or is the-3.5 the rivet of choice?.....

I used -4's on the fuel tanks and almost everywhere else -3.5's are called out. I do not experience the clinched over rivets many people seem to report. I would guess that on average, maybe 5 in a hundred are unacceptable but I have no hesitation in drilling out a bad rivet and reshooting it. Often referring to my rivet gauges, I even replace rivets that are too flat or flush rivets sitting proud. In the case of fuel tanks....wet sealer can be troublesome when shooting rivets but is a non-issue since I use the method described in the following thread.
http://www.vansairforce.com/communit...ead.php?t=7602