WOW, this is the first night in a long while where I didn't have any fuel tank work to do.  No sticky, gooey tank sealant to play with...  I MISS IT ALREADY>>  NOT!!!!  After playing with tank sealant for the last couple weeks, it made spraying ye old epoxy primer a piece of cake.  I used to think that epoxy primer was a hassle but it is nothing when contrasted to the pain the A_S tank sealant is.

I had decided some time ago that I would prime all interior surfaces on the plane.  The issue of priming is still a highly debated activity.  The only penalty for priming is weight.  For the large skin surfaces of the wing, I sprayed the minimum amount of primer to give me good coverage (good practice all the time, right?).

Here are the top wing skins just waiting to be riveted on the wing PERMANENTLY.  Could it be???

Below is the wing walk doubler.  This was sprayed on both sides.

On the wing, the there is an inboard and an outboard skin.  The outboard skin overlaps the inboard skin and is riveted together on a rib.  Where these skins overlap creates a "bump" in the skin.  To minimize this bump in the skins, Van's has you make what they call a "scarf joint".  The scarf joint is where you file or otherwise grind down 3 to 4 inches along this overlap (at the edge) to create a taper in the skins.  This minimizes the visual representation of the bump where these skins overlap and meet the fuel tank on the main spar.

I took a 1" unitized scotchbrite wheel in the die grinder and took down the edge of the inboard skin.  I also took material off the bottom of the outboard skin (I did not remove as much material on the outboard skin).  Where these skins were tapered, I sprayed some epoxy primer for corrosion control.  A fair amount of material ended up being taken from the edges of inboard skin.

Now on to the main spar you need to countersink a bizzilion holes yet.  I made a test coupon out of 0.032" scrap aluminum by drilling a #40 hole and dimpling it.  I set my microstop countersink depth and went to town.  Majority of these holes need to be deep enough to allow the leading edge and wing skin to sit flat on the spar.  However, under the inboard side of the wing, where the tank sits, there is one hole for each rib flange that needs to be countersunk only deep enough to allow a AN426AD3-3.5 (or 3-4?) rivet to sit flush with the spar (I am still looking for this in Van's instructions at the time of this log entry).  So you can't just mindlessly countersink all the holes to the same depth.  Well, you could, but those that sit under the tank skin will just sit a wee bit too deep.

To restore some amount of corrosion control on the newly countersunk holes, I just took some Alodine 1201 and a Q-tip and dabbed some Alodine in the holes.  After a couple of minutes I thoroughly wiped the Alodine out of the holes and took the air gun and blew any excess Alodine out of the holes (I took precautions to not spray Alodine in my face and eyes).  Think SAFETY!!!

I thought the holes looked really good when I was done and they should have adequate corrosion protection with just the Alodine conversion.

I went and reviewed Van's instructions and it stated to take a sharp deburring tool or countersink cutter and "touch-up" the holes on the rear spar.  Remember that these holes are first dimpled with a squeezer.  When I dimpled these holes, I thought that the squeezer didn't make a very "crisp" dimple like it does on thinner material.  The rear spar is 0.040" thick which is fairly thick for dimpling.  At any rate, the "touch-up" called for by Van's is only supposed to remove a small amount of material.  Van's says that this will make the wing skins fit better.  I already had the microstop countersink setup for countersinking the main spar, this was a fairly quick operation to "touch-up" these holes.  The countersink didn't seem to remove very much material, but the holes look alot better.  Tomorrow, I am going to use the preval touch-up sprayer I bought from Wicks Aircraft Supply.  I am curious to see how well that sprayer applies epoxy primer.