What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

primer

S

stamper

Well Known Member
Just starting to work on the rv10 kit I got and my question is I was told vans does have some protection on the metal but is it good enough. I see a lot of people with green primer and even yellow. What is best, do you use a self etching primer, can you rattle can it or is that out of the question. Nothing has been done yet and the tail section is attached to the fuselage.
Any help would be great. Thanks
 
There is a forum entitled "primer wars". People have done everything from nothing to two part epoxy paints. Parts from Vans have nothing, except the spars which are anodized. Quick build parts have a wash primer.
 
Like Bob mentioned, folks have used just a out every option available. Who's right? Ask me in forty years. It really depends on the environment and how protected is you aircraft. I.e. is it going to be a hangar or a ramp queen? Or do you live in a high humidity area or near salt water?

Some of the rattle can primers take awhile to cure. Some can also be wiped off fairly easily with acetone or mek. Some require a top coat to seal the surface.

I primed about 90% of the aircraft with akzo epoxy primer. While this is one of the better primers, it does require more effort to apply since it is a two part epoxy and the safety steps you need to take to apply it.

My thirty year old Cherokee was starting to see significant corrosion issues and I didn't want my son having to go through the same set of repairs when I'm long gone. It's still debatable how valuable the primer will be in the long run. My personal opinion is that I'll be better with it, than without it.

You are going to get all kinds of opinions on this subject. Know that priming will add a few pounds to the aircraft. Then make the decision that allows you to sleep well at night.

Bob
 
another primer story (yawn)

I used skydive out of C170/180/185's a lot, which also got used to fly salmon in Alaska. Every unprimered interior surface had that gray scruff all over it, badly corroded. The salt air no doubt, and Pacific NW winters. I swore as I built my RV that I wouldn't let that happen, so I primered every interior surface with the same stuff they use on DH Beaver float planes for salt-water ops: a two part green epoxy that would practically kill you if you didn't have a moon-suit on when applying it (ok, not quite that bad). By the time I got to the cockpit I was getting pretty weary of prepping and suiting-up to spray the stuff, so I left a few surfaces bare alum (and it looked cool too, see the pic :)

Well, 23 years later and danged if I can see any corrosion on the bare alum, and the DH Beaver float-plane primer paint appears to be indestructible (except where my heel wore through on the right floorboard, but not the left, go figure). Also, I was parked on the ramp for seven years in the Pacific NW - none the worse for wear, it seems.

Moral to the story: If the alclad is in good condition, it will last longer bare than you will. If you want the plane to go on living after you're gone, primer everything.

- Steven
700+ RV3 hours
(another one a few hours ago!)

1xkw7.jpg
 
Thanks for the pic/story Steven..

I agree with Steven about this issue. Most people's plan to use SE primer doesn't take into account that the primer itself etches into the Alclad protection, and the remaining finish is now porous, if left uncoated with paint. The 2-part epoxies are great, but very expensive and harmful to apply in the attached garage of your house.
Almost all the parts Vans supplies are Al Clad aluminum, which used to be all that was ever done in the factory produced certifieds of old (many of which are still flying today, even though they are stored on the ramp). The parts that are steel come powder coated. The instructions call for priming of the very few parts that come "un-protected" from the factory, so you will know what needs attention. The alclad holds up well if you are careful to protect it during the build process. IMHO, by the time my RV-10, with all it's beautiful Alclad surfaces, needs corrosion treatments, it will likely be grandpa's old obsolete homebuilt (i.e. neat to look at and fly occasionally, but not as fast as the ???? in the hangar next to it...). My $0.02 on primer.
 
....Almost all the parts Vans supplies are Al Clad aluminum....


Only true for the sheet material. Most (all?) of the angle material supplied by Vans is not alclad...
 
Yup. Extruded parts are not alclad, but several things like J-channel and Z-brackets, stiffeners and such, which look like angles but are actually made from sheets are alclad protected.
 
stamper said:
Just starting to work on the rv10 kit I got and my question is I was told vans does have some protection on the metal but is it good enough. I see a lot of people with green primer and even yellow. What is best, do you use a self etching primer, can you rattle can it or is that out of the question. Nothing has been done yet and the tail section is attached to the fuselage.
Any help would be great. Thanks
Click to expand...

I'm not going to recommend a primer but I'll make some general comments.

Builders who make no attempt to prime their projects will often tell you about the old unprimed Pipers and Cessnas. What they NEVER tell you is that both Piper and Cessna now prime all their new aircraft with two pack epoxy based on their experience with major corrosion problems with the early models.

The annual cost of repairing corrosion on aircraft literally runs into the billions. It's a MASSIVE problem for the aviation industry. But many amateur builders adopt the philosophy that they wont be holding onto the aircraft for that long so the corrosion will become some-one elses problem if it arises over time. In other words they're building for their own limited flying life rather than the potentially unlimited flying life of the aircraft.

Even Vans, who are known to be careful with a dollar, apply a primer to all of their QB kits. It's not much of a primer, but it's something.

It is obvious that builders who apply a decent primer to their aircraft are intent on building to the best of their abilities. On the other hand, builders who use no primer may be motivated by many factors including impatience, penny pinching, laziness, or simply a complete lack of knowledge about the effects of corrosion on aluminium. But whatever the reason, you can be virtually guaranteed that, having used no primer, they will encourage you to do the same. It obviously makes them feel better if they're not alone. ;)
 
Was watching a doco on the Ferrari factory (I think?) before paint they would dip the whole chassis in a protective solution, a big bath. I bought a SB kit, acid dipped then alodine then primer. Pain in the *** but content that the beast is protected.

Question, is it possible to dip the quick build fuse to get rid of the alclad then alodine & prime? Has anybody done this?
 
"...On the other hand, builders who use no primer may be motivated by many factors including impatience, penny pinching, laziness, or simply a complete lack of knowledge about the effects of corrosion on aluminium. But whatever the reason, you can be virtually guaranteed that, having used no primer, they will encourage you to do the same. It obviously makes them feel better if they're not alone..."

Not necessarily disagreeing with you on primer but implying people that choose not to prime their airplanes are lazy, cheap, impatient, or lack knowledge is uncalled for. There are thousands of decisions in building your own a/c, and just because some don't agree with your opinion, they are wrong?...Really?

Yes, after reading as much as I could and deliberating a lot, I chose to prime with the same stuff Van's uses on the QB...I did call Van's to get their opinion, too. They asked if I was building an airplane to last 40 years or 80 years. I guess that about sums it up...
 
I primed everything other than the interior of the fuel tanks on our RV-10. Maybe I got lazy, impatient or forgot on thr RV-14, or maybe I plan on keeping it in my heated hangar and would like to keep the weight down on this one!!! Not jumping on anyone just stating a different opinion.
 
Airliners

I've seen pictures of corrosion on an ATR-42 so bad that you could put your hand straight through a bulkhead in the wheel well. It's also a more corrosion condusive situation than most RVs will ever see.
 
Ron B. said:
I plan on keeping it in my heated hangar and would like to keep the weight down on this one!!! Not jumping on anyone just stating a different opinion.
Click to expand...

You may keep it in your heated hangar or you may live in the middle of a desert. But when you sell that aircraft to some-one who lives on the coast in Florida or who flies to the Caribbean on holiday your short term objective will become their long term problem.

I think it just comes down to a basic philosophy. Are we building aircraft simply for our own short term goals or are we building aircraft that will reflect well on the Experimental category decades into the future. In other words are we building aircraft to stand the test of time through numerous owners and varying environmental conditions.
 
I guess that's why they call it "primer wars..." I was just giving my opinion.

Suggesting that those who choose not to prime are damaging the reputation of homebuilts, is like suggesting that those flying around without a cool paint scheme, leather interiors and glass panels are doing the same thing. I totally respect those who choose to prime, and recognize that, if done correctly, it can certainly extend the life of an airframe for several generations.

Heck, if I had unlimited money, an unlimited labor force, and ONLY cared about corrosion protection, I might order my crew to fay-seal everything, install dehumidifiers & drains, build a giant humidor/hangar, and 2-part epoxy prime and paint all surfaces with the colors of my choice. Perhaps I'd even add graphics INSIDE the airframe so it'd look cool during annuals! :D

However, the many variables that affect this choice (and it IS a choice) led me to my particular decision, which is right for me.
 
I thought I did point him that way in post #3, but I didn't use the exact title.

One thing not mentioned is the availability of ACF50 and Corrosion X, which weren't around 40 years ago. Used regularly, I think they can make a difference.

And, for the record, I did prime. But if doing it again I think I would not. Without a permanent booth it just takes too much time. And then I always managed a few scratches anyway. And polluted the environment too.

BTW, I don't think you should refer to anyone who builds his own RV as lazy.
 
What the heck here is my pennies worth. I primed all parts where they mate. example: where the skin rivets onto the ribs i primed the rib flange and the skin. My thinking is that there is where most corrosion begins, holes are drilled and there is no alcad protection on those edges of the holes. I did this throughout the entire build. We do, as a group, take good care of our airplanes. I think my airplane will be fine after I am long gone. The lifespan, to me, is as long as a person wants it to be, by taking care of it.

This is only stating what I have done. I am happy. So now, I hope you do what will make you happy too!!

bird
 
Thanks for all the comments. The person who I bought this kit from did not primer the tail section, the fiberglass top is not on yet. I will primer everything I can. the tail section is not going to be much fun now but will do my best. Has anyone used the zinc chromate out of a spray can. I know a lot of airplane machanics in Alaska use this stuff. I guys they just scotchbrite and then spray it on. Anyone out there have any experience with this stuff.
 
For what it's worth, imho, the paint won't stick adequately if you just scuff and shoot.
I scuffed; de-greased (dish soap); mild etch (vinegar, as recommended by paint shop); warm water rinse (water should sheet, no drops); self-etching primer (I used automotive SEM); then rattle can chromate (which I only used at overlaps). I tried skipping steps, and the paint came off.
 
BobTurner said:
BTW, I don't think you should refer to anyone who builds his own RV as lazy.
Click to expand...

Presumably you are referring solely to the small percentage of individuals who actually build an entire aircraft from scratch and get it flying. If that is the case then I agree with you.

However it has been estimated that only 20 to 30% of RV builders who start with the empennage ever complete the aircraft. At the moment there are roughly 500 incomplete projects a year coming up for sale on VansAirforce alone. Clearly, many builders are big on dreams and ambition.... but small on persistence. ;)

As for spraying CorrosionX inside your aircraft. Well, it's a second rate solution for protecting an aircraft that was not properly primed in the first place. As others have noted it seeps out of faying surfaces forever making future painting very problematic. It also collects dust and dirt inside the airframe.
 
You must log in or register to reply here.
Back
Top