[Epsound]

Guys,

I have read many of the existing threads that give great advice and opinions on pros and cons of how drilling out rivets may or may not compromise the structure.

In my case, I have a skin that was put on before me and has not been completely riveted. (This is on the top to the wing and one on the fuse) Where the existing rivets are, the dimples are over done and rather unsightly and would require filler to get anything near a smooth finish for painting. Put it this way, one opinion of the work was that it was done by a ?hack.?

Before I go and buy new skins, my initial idea is to;

1. Drill-out and remove the skins
2. With a gentle hand and a soft (rubber hammer maybe) smooth our each over-dimpled hole and try to bring the skin back to its original flatness.
3. Re-dimple each whole
4. Re-apply to the frame and give the skin new rivets.

My question is, by doing this will I be creating 'hot spots' in the location of the new dimples? Or, if this is done carefully and methodically, will I maintain acceptable structural integrity?


I know there are stark contrasting points of view coming this way but please know that I am ok with that. I am grateful any advice.

Thanks for your input.

 

[Andrew M]

My experiance

on production aircraft has taught me this. When a rivet swells inside a dimpled hole, the hole expands a little. Every time a rivet is drilled out, the hole gets a little bigger. The holes can be brought back down to nearly the diameter by re-dimpling, WITHOUT first flattening. Dimpling stretches the metal and unstreching (shrinking) it is not a good idea, especially if it is going to be re-dimpled. Do the underlying structure as well.
This swelling poses a problem when one or two rivets need to be replaced in a panel, because it becomes difficult to rework both pieces in assembly. It can be done, however the cure is usually worse than the fix.
If you can get the skin material locally, would not hesitate to smash them all flat and use it to drill a new skin. Leaving the two pieces clecod together, cut to within about a 1/4" of the edge then use a pair of straight smooth snips to cut to size. When you are only removing 1/4" or less of material, it rolls out of the way and you can use the edge of the old sheet as a guide. Practice first.

 

[Walt]

Trouble is you don't know why the underlying structure is like, if its also over dimpled than putting on new skin won't help and may even make things worse

I definately would not flatten and redimple a whole skin, doing one or two holes won't hurt anything but not acceptable on a whole skin panel.