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Priming Questions from A Prospective Builder

BTP880

Member
To prime or not to prime?

That is the question at hand, from what I can tell this is a controversial subject. What are your opinions? Is it worth it?

Additionally im looking at building in a 2-car sized detached garage at home, I don't have room for a paint booth without building something (possible). Trying to determine if its worth it to prime and if it is, how I will do so in a reasonable manner. It seams that proper primer with the air gun and all is the way to go but this sounds like a lot of extra cost especially when I would have to build a paint booth.

Any and all advice is welcome!
 
Your answer lies in the 331 threads dedicated to the subject in the "never ending debate" section of this forum.
 
The experiences of folks with corrosion in your area, especially at local airports, will tell you if you need to prime or not.

In a dry area you probably don't. In an area where there's more moisture or industrial pollution, maybe you should.

Dave
 
Prime

You can prime outside (open air no paint booth required).

Agreed. I primed most everything outside in a barn. Interior parts were primed and painted in the barn. Often temps were close to freezing.
Whatever you choose, spray it light. Paint weight adds up quick. Especially in the tail. You only need a thin layer to protect for a very long time. That's why I chose P60G2.
If you prime, buy a good respirator or a Hobby Air positive pressure system.
If you prime, research surface prep. No primer will do it's job if the surface is not properly prepped.
 
Your answer lies in the 331 threads dedicated to the subject in the "never ending debate" section of this forum.

When I looked there originally it showed me that there were only 4 threads, didn't realize you could sort by how far back it went. Now I see that there are more.
 
As others said. Sam has a great web site. I am a fan of primer. There are areas you MUST prime. Most areas are optional.

My advice is pick a good aerospace brand of primer AkzoNobel, PPG, Sherwin-Williams for example. Brand not important, but would pick one with a local distributor you can buy direct. You will need etching and alodine solution as well. You will mix the primer stuff two part, and use a cheap spray gun is fine. The good stuff is expensive, but it will do the whole plane. Rattle can is more expensive by ounce and inferior protection.

Second advice paint in batches. Prime a bunch of parts all at one time. You can prime parts you have not fitted and touch up as required. It will save time. Setting up to prime takes time. Last this is hazardous to health. Wear good breathing protection in well ventilated area. I am not kidding. :eek: (PS you do NOT have to put it on thick)
 
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Additionally im looking at building in a 2-car sized detached garage at home, I don't have room for a paint booth without building something (possible). Trying to determine if its worth it to prime and if it is, how I will do so in a reasonable manner.

No comment on whether to prime or not (I am) BUT if you do prime you don't have to have a booth. I used SW self etching primer that Van's uses and LOVED it! Easy to spray outside and dries really quick. The best advice I have is to build a stand like the one in the picture with chicken wire. Allows the air from spray gun to keep parts stable against the screen. Priming small parts on a solid top will blow them all over the place.

I also like this sprayer from 3M. https://www.amazon.com/Accuspray-16...4?keywords=3m+accuspray&qid=1582312071&sr=8-4 Disposable cups and ends and cleanup is easiest ever! Won't give a car like finish, but it's primer.




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As other said. Sam has a great web site. I am a fan of primer. There are areas you MUST prime. Some optional.

My advice is pick a good aerospace brand of primer AkzoNobel, PPG, Sherwin-Williams for example. Brand not important, but would pick one with a local distributor you can buy direct. You will need etching and alodine solution as well. You will mix this stuff two part primer and use a cheap spray gun is fine. The good stuff is expensive, but it will do the whole plane. Rattle can is more expensive by ounce and inferior protection.

Second advice paint in batches. Prime a bunch of parts all at one time. You can prime parts you have not fitted and touch up as required. It will save time. Setting up to prime takes time. Last this is hazardous to health. Wear good breathing protection in well ventilated area. I am not kidding. :eek: (PS you do NOT have to put it on thick)

I have found these articles that talk about alternatives to alodine:

http://myrv14build.blogspot.com/p/priming.html

http://rvplane.com/priming/

I like these methods as they avoid having to deal with the alodine. Anyone have any experiance with them?
 
I have found these articles that talk about alternatives to alodine:

http://myrv14build.blogspot.com/p/priming.html

http://rvplane.com/priming/

I like these methods as they avoid having to deal with the alodine. Anyone have any experiance with them?

That is why three are +300 threads and 1000's of post. Use what ever you want. However "aerospace" materials and processes have been tested and are well understood. If you spend all your time researching and reinventing the wheel it will take longer to build, Just buy the proper materials and apply per the instructions. Alternative may be adequate but never better. In fact leave it bare clad. Save a lot of time and money (except for aluminum with no clad or where aluminum contacts with steel). There is really no reason to use alternatives, and cost of a few extra $100 on a $80,000 airplane is trivial. Up to you. Time matters. (PS primer has shelf life, if you buy a gallon and 5-10 years to build it will go bad, buy quarts)
 
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Alclad vs not

Any parts made from aluminum sheeting will be Alclad.
Other aluminum material that is from: bar, angle (extruded, not bent), tubing etc. is not Alclad.
My kit has very little blue vinyl used and there are smaller parts without any alloy type identification.
 
Blue Vinyl

Any parts made from aluminum sheeting will be Alclad.
Other aluminum material that is from: bar, angle (extruded, not bent), tubing etc. is not Alclad.
My kit has very little blue vinyl used and there are smaller parts without any alloy type identification.

You mention that you have very little blue vinyl, and if you mean that you have an older kit with the clear vinyl, then it's still the same. .the sheets and ribs are alclad
 
Old kit

You mention that you have very little blue vinyl, and if you mean that you have an older kit with the clear vinyl, then it's still the same. .the sheets and ribs are alclad

Yes mine is an old, actually very old kit, relic from mid 1990's and there is no vinyl at all, neither clear, nor blue, on any of the original parts. And there are no pre-punched holes either! :rolleyes:

I bought some spare Alclad sheet in 2000, and it has blue vinyl. Incidentally, there is filliform corrosion under the vinyl, starting from the edges, whereas the original parts are fine!
 
I'm just using rattle can self etching primer on the faying surfaces, just because of the potential for water to get in there (and obviously on stuff that isn't alclad). But, this shouldn't be a one size fits all approach.

In my case, I split my time between the midwest & arizona, and I've been around enough old midwest airplanes from the 50's & 60's that I don't believe whether I prime or not is going to matter much.

If I lived on the coast where it was going to be in the salt air 24/7 it would be a completely different story and I would prime everything.
 
Just remember, if the part is going to be eventually painted (e.g., skins), the primer beneath should be fresh for proper adherence. Otherwise, it should be at least scuffed or reprimed. :rolleyes:
 
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