Fixin pimples....

[pierre smith]

Okay all you multi RV builders,
Yesterday I looked at a -7 empennage with pretty good construction that may be for sale.

The one elevator has a serious "pimple" on a rib/stiffener on the top skin where a rivet is located. They must not have had the skin tightly down on the backing bar when they rivetted that one and it stands proud, as the Brits say. The entire elevator is closed up. What is the way to fix it, or is there a way without removing the skin. Drill it out and whack it carefully with a ball peen and pop rivet? Ideas?

Thanks,

[vmirv8bldr]

You can try to drill it out, replace with a pop rivet, like a Cherry Max, and then fill the hole in the pop rivet. It will look like the others.

[RScott]

I was told to use a spoon and rock it around on the bump. Haven't tried the technique yet.

[Steve]

I asked the same question of Kent White at the metal forming class at Oshkosh this year. Per Kent, we have 2 problems here, the aluminum is now locally work hardened and access for a bucking bar is now impossible. The fix involves using a slapper bar, made from spring steel, to tap/hit the pimple flush to the surface. The process will go easier/faster if the inside surface can be supported with something. Kent favors a plastic harder than delrin.

www.tinmantech.com

Steve