Weight of Primer

[BrianP]

Hi Everyone. I just finished unboxing the emp/cone and wing kits. Planning to start construction soon. Trying to decide if I should prime? Does anyone know what portion of builders do this? Any idea how much weight it adds to the RV-10?
I live in central Canada not near any salt water and the plane will park in a heated/dehumidified hangar. Might fly to Vancouver once or twice a year where it will likely park outside fairly near the ocean. Any thoughts or suggestions?

Thanks

 

[bertschb]

If you do a search on priming, you'll find enough posts to keep you busy reading about priming for a couple days. Literally. I've spent several days reading on the topic and like you, I'm not near the ocean and my plane will be in my hangar - and I'm still undecided! I may end up flipping a coin. Good luck!

 

[wirejock]

Hi Everyone. I just finished unboxing the emp/cone and wing kits. Planning to start construction soon. Trying to decide if I should prime? Does anyone know what portion of builders do this? Any idea how much weight it adds to the RV-10?
I live in central Canada not near any salt water and the plane will park in a heated/dehumidified hangar. Might fly to Vancouver once or twice a year where it will likely park outside fairly near the ocean. Any thoughts or suggestions?

Thanks

I calculated it for my 7A with P60G2.
Difficult to get exact numbers because the weight change on small parts is so little, but the parts I weighed gained basically nothing. P60G2 is very light. Epoxy would be significantly heavier. If you can get ft², it's simple to estimate.

 

[BrianP]

Maybe a better question to ask would be if anyone has ever seen corrosion in a non-primed RV?

 

[Dustyone]

Yes, RV-14A 140hrs 5yrs old

This aircraft had a landing mishap that required the belly skin to be removed.
Aircraft was stored and built in-land Australia.
The foam trapped in condensation moisture.

Water leaks or wet carpets will do the same.

Not the corrosion 2" above the floor on the electrical conduit stand-offs

Any primer, even rattle can primer like Rust-Oleom would help a lot.

 

[Ron RV8]

MDRA inspection form has a tick box for "corrosion protection" or words similar...

Be prepared to justify not priming...

I ended up priming faying surfaces which ended up overspraying most of the surface between...

 

[Mel]

This aircraft had a landing mishap that required the belly skin to be removed.
Aircraft was stored and built in-land Australia.
The foam trapped in condensation moisture.
Water leaks or wet carpets will do the same.Not the corrosion 2" above the floor on the electrical conduit stand-offs

I would be hesitant about comparing "foam induced" corrosion to lack of primer.

Not exactly apples to apples!

I've been an A&P for almost 50 years and can tell you that corrosion is pretty rare inside unprimed general aviation aircraft.

 

[PaulvS]

I think it's worth corrosion proofing at least the faying surfaces because moisture can become trapped there and also the alclad protection has been removed due to the rivet holes and the sheared edges.

As an indication of added weight, it took 6 litres of zinc chromate primer to fully prime the inside of my RV-6A, which is obviously smaller than a -10. If half (or more) of the paint was solvent that evaporated or ended up as overspray then the added weight would be around 3 kg.

 

[Tommy123]

I have worked on plenty of corrosion on Boeing and Douglas aircraft that were fully primed, everywhere. Any aluminum parts that are constantly subjected to fluids will corrode no matter how much primer you apply and I very much doubt any homebuilder is going to get Boeing results on primer application in their garage.

 

[jack202020]

I started my empennage kit in February and read the arguments for hours... switched back and fourth a few times. I eventually decided not to prime (mostly). I prime any non-alclad material, and I'll be priming the interior areas that will be hard to inspect. But that's just my decision/opinion as new builder, in a sea of the never ending argument...

To answer your question about how many builders do, in my research I found this thread. As of right now, 86% of votes indicate that they did prime.

 

[EMacGill]

I recall primer adds about 10 lbs.

As mentioned by Ron_RV8, you must build to Canadian standards.
- any closed in sections which can't be visually inspected must be "treated against deterioration" eg primed
- fuselage, wings, control surfaces, must be "protected from environmental deterioration" eg primed

I recall the Inspector being especially concerned the lapped joints and counter-sunk holes were primed.

Contact the Minister's Delegate for Recreational Aviation (MDRA) for specific guidance.

 

[planenutz]

Maybe a better question to ask would be if anyone has ever seen corrosion in a non-primed RV?

Yes. Eventually, always.

Any aircraft located in a coastal environment is very susceptable. Having spent a lifetime as a maintainer removing corrosion from both inside and outside airframes I would take the added weight of some primer 100% of the time.

 

[Everwild]

I'm using AKZO and this is the listed dry film weight

.0093 lbs/ft2 at 1 mil

Now the trick is to figure out how many ft2 you have

I'm priming, but it does add a considerable amount of time and work to the build if you are taking your time to do it right. Prep, scuff, degrease properly and then spray. A guess is it's adding about 10%-15% to my build time and minimal cost in the grand scheme.