countersinking fuel tank skin

[rwshooter]

I'm about to countersink the tank skin to baffle fit on my 7A fuel tank. Should I go a couple thou deeper to allow for the proseal? It would seem to coincide with the logic of using fuel tank dies. right?

Robb 7A

[Brantel]

If I had it to do over I would.

Several of my rivets on the baffle will need to be shaved before paint due to them being proud of the skin.

[Thermos]

Robb,

Here's one data point...I didn't go any deeper than recommended by Vans. IIRC, the skins are 0.032", which is the bare minimum for countersinking to accomodate an AN426 rivet. My skin-to-baffle rivets actually sit a little proud because of proseal, and I figured that was better than making deeper countersinks.

There's some good information in this thread...

http://www.vansairforce.com/communit...ead.php?t=2322

about your question.

Hope this helps,

Dave

[Flying Scotsman]

I did, and probably would go a little more still if I did it again...can't tell you precisely how many more thousandths, but I did increase the depth a few...

[rwshooter]

Im afraid of violating the .032 rule Dave thats why I'm asking............but if there is proseal in there do you think it would really matter.....

Brian...... I've never heard of a rivet shaver I dont think.......I remember having to sand down a couple of blind rivets on the emp during fiberglass work....they came out just fine.....but they are under glass work..../so no biggie............so if I get some proud rivets, this rivet shaver will take em down before paint?

[allbee]

This is interesting, I dimpled all mine, with proseal on all the rivets. Is this wrong, I don't think so. I know this has been talked about before and I was told this is wrong. But it says in the manual, not the plans, to dimple all tank skins. So I did. It looks good and it doesn't leak. I think dimpleing is stronger and less chance of a crocked hole, or a line in the hole for a leak. I'm not reduing mine, they stay the way they are. I even remember reading one of the tool suppliers having a dimple die for tanks to make the rivet set lower for proseal.

[Brantel]

I think we are talking about the skin to the baffle rivets. I also dimpled all the others.

[mackd]

I didn't on my first tank, and most of the rivets ended up a little proud. I went slightly deeper on the 2nd tank and it came out perfectly.

[sglynn]

I just did my skin holes for the baffle and I made the countersinks so that the rivets were flush or even slightly indented, but after riveting with Proseal, I have many that are slightly proud and I'll have to smooth them off later. You can see them at mykitlog/sglynn

[airguy]

On my 9A, I countersunk the main skins for the baffle rivets in the .032 skin per directions. For my auxiliary outboard tanks, the skin is .025 so I dimpled them with the tank dies. The rivets set beautifully in both, and I will be pressure testing them this weekend. I'll keep all here advised.