Can't untwist tank ribs

I'm wondering if this is normal? I can not untwist the twist in the tank ribs. I have fluted them, and if I lay it down on the bench, one corner of the rib will pop up. I can press down with a finger on each corner and it will lay flat against the bench, but as soon as I lift a finger, a corner will pop up.

No matter what I do with the fluting, there is still a twist in the rib. Does this matter? With much moaning, groaning, and swearing, I am able to cleco them to the tank skin. I suppose the skin holds them without the twist, but I just want to make sure this is ok because right now I'm ready to take a sledge hammer to the **** thing.

That is fine as long as rivet holes are lining up and clecos go in fairly easy. Keep at it...it is really worth it!

Sometimes the face of the rib has bulge in it. You might try laying a straight edge down the length of the rib to check. If that is the case, don't worry about a little twist when the rib is laying on the table.

As Wayne says, keep on working.

Ok thanks-I'll presss on...

Just fitted mine today and had the same issue. The fluting actually made it worse but was necessary cause the fit was so tight. I found working on the top side first and putting in clecos in the first few leading edge holes and then flipping it over and putting a cleco in the most aft hole worked pretty well. I had to then tap the sides of the rib lightly with a dead blow to help the rivet holes into alignment and it worked like a charm.
My only problem was apparently I was sent an extra interior rib and not sent outboard rib. Doh! This is the right tank, the left one is done so I haven't gotten anything mixed up. Now I've gotta wait a good solid week for the rib to arrive. So it's on to something else for now.

Twistin' the night away

I had the twist as well. The holes lined up but, clecos were a tight fit. I used a dead blow hammer to tap (and I mean just a tap) the ribs into position. When final drilling, cleco every hole except the one being drilled. Replace the cleco and move on to the next hole same procedure.

Sweet! I hope to finish up this left tank today and have it fitted to the wing.