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RV-12 so do I prime or not ?

Cdenora

Cdenora

Active Member
IM so sorry to post this stupid question , but I kneed to know as I have read yes and no answers and its not clear to me I live in a low humidity environment but would like at least the minimum protection to guarantee the best results , and If I sell the plane I would not like to be limited by the corrosion resistance , want to keep it light to.

Im about to start my kit and im totally confused , what would be the minimum ?
 
The MINIMUM is the parts that are not alclad. In the instructions tell you where to prime. Check out section 18 of the manual for instance and it tells you to prime the flaperon brackets.

Everything else is an optional "improvement"
 
common thing to see in a rv12

so other than the specified sections that must be primed, what would be the common thing to see in a kit like this ?
 
Alex Edwards said:
The MINIMUM is the parts that are not alclad. In the instructions tell you where to prime. Check out section 18 of the manual for instance and it tells you to prime the flaperon brackets.

Everything else is an optional "improvement"
Click to expand...
so other than the specified sections that must be primed, what would be the common thing to see in a kit like this ?
 
Some have primed every piece and the inside of the skins. The outside will get primed if painted. We primed parts that overlapped in the structure. As far as the interior section of the cockpit, primed almost all of it since it will get touched and walked on. Not a big deal if you get the carpeted interior. We used SEM self etching primer from a spray can. It has held up well for 2 years of flying now. Minimal prep. Anything that is going to be visible once your done should be primed/painted for protection but as the argument goes.... That's optional.

Also used corrosion X on the finished product in the wings and tail section. A little goes a long way. It's a spray can style application.
 
The minimum is what the plans require, but the minimum to guarantee the best results depends on what you mean by `best results'. A brief on-line VAF poll I did when I started my build suggested that about 50% of RV-12 builders do no more than the minimum required priming, 25% primed overlapping surfaces, and the remaining 25% primed everything. The results might be different for other RV's, and it might also reflect the observation that most RV-12 builders are getting on in years and probably figure that the plane will outlast them anyway, so the time saved by not priming could be better spent flying. :D
 
My Cessna, unprimed, is 59 years old. It's spent most of its life in the dry states, but a handful of years, single digits, near the ocean. It has some light corrosion where there are lap joints. For example, between stiffeners and skin. Not all of them, though.

I'd say that a single layer of prime on one of the mating surfaces of a joint would be sufficient to guard against that. Perhaps on rib flanges.

On the other hand, judging from the number of people priming every last part, that must have some perceived desirability. And that's what I'm doing on my RV-3B, simply for resale value.

Dave
 
Section 5 on primer says it all. Personally - I've found that it at least adds 33% to the build plus the weight. Not recommended by someone who's doing it. My Cessna is a 35 year old FL plane that has held up well with Corrosion X. Do not apply Corrosion X until after it's been painted.
 
The three 12 projects I've done have not been primed other than where the plans specifically call out primer. These specific call-outs mostly regard parts formed from other aluminum alloys.
 
waterboy2110 said:
... Personally - I've found that it at least adds 33% to the build plus the weight ...
Click to expand...

I'm priming everything with AZKO and I'm sure it has added at least 33% to my build time. However, I also plan on selling the -12 that I'm building soon after I get the flight testing done. I think having a fully primed interior will add value for a potential buyer living in a humid or coastal environment.

If nothing else, the AZKO green looks really cool. :)
 
I was being conservative at 33%. Basically I assemble everything twice and clean it 3 times. By the time I'm actually pulling rivets I know the parts intimately.
 
Priming

waterboy2110 said:
I was being conservative at 33%. Basically I assemble everything twice and clean it 3 times. By the time I'm actually pulling rivets I know the parts intimately.
Click to expand...

The estimate is probably right on. I'm priming all inside parts too. Scotch brite every surface, clean, prime. Easy 30%.
 
Just passed 700 hours in the build log - 100 hours of that is prep and prime with Akzo. My percentage is probably a bit low as a first time (read slow) builder. I wouldn't do it any other way, however. Well worth the effort IMO.
 
wirejock said:
The estimate is probably right on. I'm priming all inside parts too. Scotch brite every surface, clean, prime. Easy 30%.
Click to expand...

Yeah, I confirm this too. Prepping, cleaning and priming all interior surfaces was about a third of my build time. Would I do it again? In Arizona, probably not, maybe just overlapping/touching areas. In Florida, absolutely!
 
Thanks to all of you I have decided that I will prime all the interior and even go an extra step and paint all that is visible as I think it will have better view and resale value to it, Im in no hurry to finish ( of course I just started )
 
how do you prep for primer ?

how did you guys prep for the primer ? I was told to wash the parts with a soap that would remove any oil or grease , dry well and then directly prime is this correct ?
 
Prep

Cdenora said:
how did you guys prep for the primer ? I was told to wash the parts with a soap that would remove any oil or grease , dry well and then directly prime is this correct ?
Click to expand...

That's almost as loaded a question as which primer. I would start with the manufacturer recommendations.
I prime with Sherwin Williams P60G2 and use a product they recommend. I clean off blue vinyl residue with laquer thinner, debur, scotch brite, dimple then clean with AeroGreen 4110. It was recommended by Sherwin Williams and it's environment safe. I'm sure others will comment with their preferred method.
YMMV
 
Scuff the surface thoroughly with maroon Scotchbrite, wash using a mild dishwashing liquid, rinse with running water to remove all traces of detergent, allow to dry thoroughly and prime.
 
It is probably better to wash first then scuff and then wash again so you don't spread around oily finger prints and such
 
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