Fuel tank repair question

Yes, I did it. While working on my fuel tank I dropped the 1.7 lb tungsten bar. I had foam in place against the rib flange but the bar landed in a very small unprotected area adjacent the tabs at the nose section of the rib. It produced a .018? dent outward and a small crater type ding on the inside right on the most fwd part of LE of tank. I was able to massage dent back in and sand/feather out ding on the inside. The end result is an area about 1-1/2? dia skin reduced to approx .020? (original is .032?). The plan is to proseal on a doubler over damage. My question is this ?has anyone done a similar repair, anywhere on the plane, and had issues with it down the road??

Side note: I made up a small piece of the tank section out of .032? material and dropped the bucking bar into it 6 times from the same 21? height. I wanted to try and replicate the damage and try my repair method on it before going at the tank skin. In the process, out of the 6 drops 3 of them punctured the skin badly. I only mention this to make sure everyone is using suitable protection when completing this step. The foam I was using, in hind sight, was not enough.

I did a similar thing on the leading edge skin. Not quite the same dynamic since there's no fuel. I have set it aside while contemplating repair methods so I'm watching this thread.

So I dropped my fuel tank when I was moving it from the work bench last year. Put a nice dent/cut on the edge of the skin. I’ve done a lot of tig welding in my years and thought about doing that but aluminum is challenging. I just tried a practice piece using a aluminum brazing rod with a propane torch on .032. It actually went pretty well. Heated up the skin in about 20 seconds with no warpage. Just smoothed it out with a scotch bright wheel. Going to have a cup of coffee and try it on the real piece. Might be an option for you to fill in the divot.

Aluminum brazed the crack on the edge of my tank skin. Went very well I think.

Well, you've just ruined the structural integrity of the tank by destroying the heat-treatment of the aluminum. And the tank sealant might have been ruined, too. It's unairworthy until the heat-affected parts are replaced. Recommend that you call Van's support when they open.

Dave

Discussed it with my A&P/IA. For the 20 secs and 1 inch area that was heated there was no concern and wasn’t anywhere near the sealant.

Contact Van's. An A&P/AI should know better. The A&P/AI does not know what the stresses are or the fatigue life requirements.

Dave

Looks great and on the edge. I would not worry about the structural integrity of the tank.

Usually, the greatest stress is near the edge. In this case, it's close to the mounting holes. Call Van's support.

Dave

I doubt it

You could fly the plane it’s entire life without a screw in that location with no problem. If you’re talking about heating up the wing spar that’s another story but structural integrity of the tank in that location, I don’t think so. The tank is screwed to the spar, there is hardly any stress on the tank in that area. Is it possible it heated up enough for the proseal to fail, maybe. If it does eventually leak, no big deal. Cut a hole in the baffle and reseal that area.

The owner did a great job repairing it!

Todd, what happened to the link of the pic you posted? Repost it so others can see what you did.

Looks great.
No threat to structural integrity.
Inspect during preflight for any anomaly.

Consensus of 7 builders on my strip.

R