To prime or not to prime, that is the question.

[AX-O]

I don't want this to be a primer war I simply want to know if you primed the ribs and skins on your wings. If you did, would you do it again? Did you use something other than primer? My EAA TA (also aircraft mechanic) told me he likes to see clean alum when doing inspections vice primed. Primer hides corrosion very well. He also told me that primer does not protect the alum against moisture. That it is a misconception. Oh yeah, another question. Why would Van's instructions tell you to rivet the front and rear wing spars to the ribs (part previously primed) before drilling the wing skins to the ribs. Seems like after drilling and deburring the parts, another coat of primer would have to be applied to the holes.

Edit:
I forgot to mention that the TA has an amphibian aircraft and did not prime or protect the inside of his wings.

[bullojm1]

AX-O,

I am building the wings right now and have thus far been using the AKZO epoxy primer. From what I understand, it also is a sealer (i.e. not meant to be topcoated) so it provides a moisture barrier. Other primers such as marhyde, GBP-988, and even the wash primer that Van's uses on its QB kits are meant to be topcoated. I did not prime the skins of the empannage, but I do plan to with AKZO on the wings and fuse.

True, you do have to rivet the main ribs to the spars before you match drill the skins. Then you have to dimple the ribs while riveted to the spar. The manual doesn't say why, but I believe that if you were to cleco the ribs to the spars, level and de-twist the wings, match drill the skin, prime and rivet everything together you might have a twist or some other issue with the wing. Personally, I would rather have a very small bit of a #40 hole without primer than a twisted wing. I think that the rivets squeezed into the unprimed holes will provide a good barrier against corrosion. When you drill out a rivet and pop its head off, the rivet is almost one with the structure.

Just my thoughts, YMMV, etc..

[yakdriver]

I live in a dry climate. The club I belonged to has two 30 year old 182s and there isn't a speck of corrosion anywhere. I am doing very little primingon mine. If I lived near the coast or the northeast I would prime. Don

[TShort]

I primed the wing ribs and all bare structures with AKZO; primed the inside of the LE skins with AKZO. I did not do the main wing skins. These were easy to keep scratch free and are easy to see on inspection. All tail parts are fully primed internally with AKZO.
My thought was to hit everything that I cannot see and inspect easily with AKZO. Skins like the main wing skins that are scratch free I just left bare.

Thomas

[N674P]

Originally Posted by TShort

Skins like the main wing skins that are scratch free I just left bare.

Thomas

On the tail I primed everything with a 2-part self etch primer. I switched to SEM self etch primer, which comes ready to spray in quarts or rattle clans. I also gave up on priming skins, since virgin ALCLAD resists corrosion very well. I am priming parts that I fabricate, or have been subject to radical forming, like ribs.

[Captain Avgas]

Originally Posted by AX-O

I forgot to mention that the TA has an amphibian aircraft and did not prime or protect the inside of his wings.

I highly recommend getting a new TA.

[TSwezey]

Yes, I do want the plane to out live me. It all depends where you live. Coastal areas yes I would/am priming. Middle of the desert I guess not. Not priming a sea plane plain (plane) stupidity.

[johngoodman]

Originally Posted by TSwezey

Yes, I do want the plane to out live me. It all depends where you live. Coastal areas yes I would/am priming. Middle of the desert I guess not. Not priming a sea plane plain (plane) stupidity.

Not necessarily, I have been flying with the Kauai CAP for a number of years and our experience is that primer ain't the ointment of choice. You can't fight corrosion with anything that can't actively stop the moisture from getting into the tiniest crack. I know the new primers are great, but when we get a new airplane (technically seized), we don't care. The ACF-50 bath begins....