Fuel tank bracket pop rivet problem

The good news: I finished up my first fuel tank today.

The bad (?) news: when I pulled the AD42H pop rivets that attach the Z brackets, on about a third of them the stem broke off inside the rivet gun, instead of at or inside the rivet. This left more than an inch of the stem sticking out. I figured my old trusty rivet gun must be having a problem, so I ran out and got a new one. The new one grabs the stem a bit lower and when I re-pulled the rivets the stem broke off lower, but still not at the rivet head. I'm convinced the rivet is actually pulled, so I just cut off the stems with my Dremel tool cutoff wheel.

Anyone else had this problem?
I'm going to call Vans in the morning to see what they have to say about this.

Dennis Glaeser
7A Wings

Rivet stems

Dennis,
Yes, from what I've read it's a common problem. I finished my first tank a couple of weeks ago and I had just one break off high. I got lucky I guess.

Mark

Tank Pop rivets

Thanks Mark. Where did you read this as a common problem? I did a quick search (here and Matronics) and didn't find anything - but my search wasn't exhaustive by any means.

I just spoke to Ken at Vans - he said no big deal as long as the mandrel broke off somewhere and didn't pull through. He said you could even just leave the mandrels sticking out (as long as they didn't interfere with anything of course). He said those are just commercial grade rivets - nothing special or structurally critical.

So, back to our regular programming (drill, deburr, dimple, rivet - repeat) on the rest of the skins.

Dennis

Hi Dennis--I just asked the same question about a month ago and got some good responses...

http://www.vansairforce.com/community/showthread.php?t=2934&highlight=mandrel

Good luck.

Pop rivet mandrel

Thanks Steve! I didn't think to search on 'mandrel' - would've answered my question before I asked. Strange behavior for a pop-rivet.

Dennis

DGlaeser said:

Thanks Mark. Where did you read this as a common problem?

Dennis

Click to expand...

Dennis,
I'm not sure where I read it, probably right here. But I do look at a lot of builder web sites too.

Sounds like we are at about the same stage of building.
Keep going!

Mark