[tegwilym]

I'm still in need of a good idea for a paint boot, but until then I'm doing what I can to keep building. I just got to the part of the RV7 plans where I countersink the upper flanges of the F-704 bulkheads and then rivet the nutplates on.

Question: do I prime these nice looking bulkheads before I put in those nutplates or do I not? Seems that a lot don't prime these, but some do.

Kinda stuck again.

Tom
RV7A - Empennage done
Standard build fuselage started.

 

[wirejock]

Prime

It's up to you. They're alodined. No need for primer and no one will see them.
Leave the nut plates off where the gear bolts on. They are in the way. You can install them later. Had to drill me out to fit the gear towers.

 

[aeroaddict]

Agree with the idea that the carry thru spar, which has been anodized, does not need to be primed for corrosion protection.

BUT, I would prime the c/s holes where the anodize/material has been removed. I just used a rattle can self etching primer and sprayed the flanges to cover the c/s holes.

 

[tegwilym]

Ok that sounds reasonable. Thanks guys! Good idea about the holes, I have used rattle can primer for the empennage, but we are still trying to figure out a good paint booth to do the larger fuselage parts.
I've been working around stuff that needs priming, but I need to get that done so I can actually rivet stuff soon. I'll prime and squeeze in those rivets.

Thanks,

Tom

 

[RV7A Flyer]

Agree with the idea that the carry thru spar, which has been anodized, does not need to be primed for corrosion protection.

BUT, I would prime the c/s holes where the anodize/material has been removed. I just used a rattle can self etching primer and sprayed the flanges to cover the c/s holes.

Or use alodine (for holes of small to moderate size w/ a c-sink, a drop of Alodine will form a meniscus so it stays in place and in contact with the aluminum). Wipe well with a wet cloth after a few minutes, both sides (don't leave Alodine to dry on the part!).

Did this with the gazillion countersunk holes on the spars.

Probably WAY overthinking the whole thing, anyway. I imagine there are probably only a few thousand planes flying around built by people who just countersunk where needed and moved on, not bothering to alodine OR prime the countersunk holes

 

[wjb]

The only priming/additional protection needed is where you countersink the nut plate holes - where there is bare aluminum. The anodized surface is more than protection enough from general corrosion. However, if you plan to paint in inside of the cockpit, consider cleaning and priming the vertical pieces that fasten to the side skins at least from the top of the main section upwards (starting at the base of the triangular section). Parts of this will show in the final cockpit, and some primer here will help with adhesion of the top coat.