Correcting a dimpling screwup

Thermos · Post by **Thermos** » Mon Mar 17, 2014 4:23 am

Hi all,

When dimpling the upper forward fuselage skin - the one in front of the canopy - I inadvertently grabbed my #4 dimple die set and dimpled 7-8 holes on the aft edge of the skin. Fortunately, I realized my mistake before I did the whole edge!

The dimples are well-formed, but they're just a little too deep for a -426 rivet so I'm not sure the rivets would set properly. I'm considering taking my pneumatic squeezer and flattening those dimples ever so slightly. Or, I've seen Vans recommend using some JB Weld to fill in over-countersunk holes. Replacing the whole skin would be an option, but I don't think it's necessary.

Any other thoughts on how to overcome this?

Dave

leffler · Post by **leffler** » Mon Mar 17, 2014 7:04 am

Vans will recommend just flattening them, then use the correct dimple. You do need to watch for potential tears and/or cracks.

Trust me, you aren't the first to do this. You shouldn't have any issues. Just don't repeat the process in the same hole again.

Post by **bullojm1** » Mon Mar 17, 2014 7:40 am

Dave,

Van's always give the advice that you can re-dimple once and not have it cause excessive weakness. I don't know if you even need to flatten the malformed dimples before you re-dimple them to AN426's. If it was me, I would intentionally dimple a scrap sheet of aluminum with #4's and practice different ways to correct it.

dpansier · Post by **dpansier** » Mon Mar 17, 2014 7:44 am

Dave,

I did the same thing in a few holes and did the following:
I duplicated the incorrect dimple in a scrap piece of Aluminum and re-dimpled with the proper size dimple, I found it corrected the problem nicely with no cracking and with the minimum reforming of the metal.

Give it a try on a piece of scrap to see if it meets your standards.

captain_john · Post by **captain_john** » Mon Mar 17, 2014 5:40 pm

First of all, edge roll that aft edge before you go any further!

It has a propensity to catch on the canopy when you open it!

Why not just use 1/8" rivets instead in those locations? Nobody will ever notice.

CJ

Vlad · Post by **Vlad** » Mon Mar 17, 2014 6:34 pm

captain_john wrote:

Why not just use 1/8" rivets instead in those locations? Nobody will ever notice.

CJ

I am with John rivet 1/8 it will be painted anyway