What to do about the primer on this rear spar

So my wing kit was started by a different builder. He built this rear spar.
Its primed in just some self etching rattle can stuff i don't really care for.

I just ordered 2 gals of akzo

What do you guys think i should do with this. Im afraid to take the primer off with acetone because if its gets between the two pieces it might eat the primer between the parts thats are already riveted. Im obviously not going to buy a new spar nor am i going to drill out all this work and take it apart.

Any thoughts on how I can shoot this with it being half primed already?

MEK and a plastic brush should take it off. You're going to have to etch and/or scotchbrite the spar prior to the Azko. I etch and alodine, but, you know...primer wars.

Prime

Personally, I would scuff all of it with maroon scotch brite, scrub with Bon Ami and grey scotch brite, rinse well and shoot it. But that's just me. YMMV

Primer sticks well to primer. Lightly wipe with acetone or some other degreaser (final kleen is another product), scuff with scotchbrite, and give it a squirt.

I wouldn't do a thing. The primer used is more than adequate and when you paint the wing you will prime for the color coat including that area. No need to spend more time.

Thanks for all the replies. Really appreciate the ideas.

fl-mike said:

MEK and a plastic brush should take it off. You're going to have to etch and/or scotchbrite the spar prior to the Azko. I etch and alodine, but, you know...primer wars.

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How is that working out for you? I know some people that have tried that. I have heard the akzo has a tuff time adhering to the alodined surface. Is that not the case? I have a gallon of alodine in the shop. I was considering trying it. Its an old gallon but was told that if its been stored out of sunlight it should be ok. If the parts turn gold they are good to go. If it doesn't turn gold throw it out. I have a gallon of alumiprep to try however i was eye balling that Prekote stuff spruce sells.

My concern is taking that primer off with a chemical like MEK or acetone and some of the chemical seeping between the parts that are riveted. Compromising the primer between the parts.

Im considering just scuffing the primer on there with a scotch brite and spraying the akzo on top. That way I'm not compromising the parts inside. I live in colorado but there is a chance i could move to a costal city for a job. I don't want to turn down a good job because my airplane is not primed well. I have shot the stewarts water based primer and trust me I'm not thrilled with having to prime either. I would love to be using rattle cans for time savings I'm just afraid if i have to move to florida someday we will be screwed. Im only 30 and planning to have the airplane a long time. I need to build it to last. So although i hate the idea and the work load, akzo it is for me.

I'd leave it.

Only prime new pieces.

Dave

Leave it alone and build-on! Actually no primer at all is fine.

Mel said:

Leave it alone and build-on! Actually no primer at all is fine.

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Especially considering you live in Colorado.

I used self etching SEM rattle can primer on my plane and seven years and 700 hours later it looks as good as the day I painted it.

I wouldn't try to remove it and just build on.

Just an opinion,

Robert that gray primer actually looks really good on there. I'll second what Bill said about it's quality and durability. I have used many different brands of rattle can primers on my RV-7 and the stuff I sprayed on 10 years ago is still looking like new (my fav.. is SEM self etching). The wing is so labor intensive I think you will get SICK of the extra work of applying the Akzo. It's really good primer but after talking to a few friends that used it on their RVs, they say they wouldn't go through all that again.

leave it

Leave it alone.
That looks like my "favorite" rattle can primer SEM self etching.
SEM is not cheap and the ease of priming out of a rattle can will quickly
become your favorite way of priming.

The stuff on there is actually a napa product. It lays down very smooth it seems and its reasonable strong. If you rub a bucking bar on it however forget it. Its coming off.

It reminds me of some car that someone botched some body work with in their driveway

If i knew 100% i was staying in CO i would 100% use the rattle can method. I have done both types. I shot the stewarts one part which was a ton of work and also the rattle can. The work load as you all have mentioned is much different. The rattle can stuff sure is quick and easy. I would be interested to see a plane painted with rattle can primer that lives on Seattle or florida.