Painting out drive

[1979 Quartermasters]

Went to the paint store to pick their brains about painting my out drive. They recommended this stuff. Also he said i will need to strip all the pain off with this stripper he recommended. He also said both products were safe on aluminum. This is a re branded version of Por15, if you guys are familiar with that product.



All opinions welcome.

Thanks,

Ken

 

[1979 Quartermasters]

Sorry, the pictures aren't very good. The products are KBS Coatings, Rust seal. The stripper is called KBS Coatings, Strip Paint Remover. Has Marine on the label. Directions state both products are safe for aluminum.

 

[tpenfield]

My rules on re-painting outdrives . . .

1) Don't take off any more paint/primer than you have to.

2) Use a primer that is made for underwater use on aluminum. (Like Interlux Primecon)



3) Don't spend a lot on the topcoat paint. A can of Rustoleum Black (for Mercury) will do fine.



I don't think you have the right stuff, particularly that rust seal stuff . . . aluminum don't rust.

 

[1979 Quartermasters]

Thanks Ted for your response. I said the same thing about aluminum not rusting. They said it was developed for applying over rust to seal it off to stop the oxidizing process. Point is it will adhere to the aluminum in a permanent way and seal it off. Its a polyurethane. I'm no chemist, but thought this might work. It's also self leveling and very shiny. Isn't the propose of the special primer to promote adhesion?

Ken

 

[1979 Quartermasters]

Just wondering if some could look into their crystal ball and tell me what the worst case scenario would be if I coated this drive the way they are suggesting. I have used this product before, just not on aluminum. It worked very well. It sticks like you wouldn't believe and is very durable. In fact, if you get it on your hands, you have to wait for it to wear off. Don't ask me how I know. lol

Ken

 

[1979 Quartermasters]

Could some one explain the purpose of the "primer made for under water"? I'm just wondering if using this paint system will harm the the drive, or promote corrosion, etc. If its just an " adhesion" issue I might be willing to try it. Every year, at the end of the season, my pressure washer blows a lot of the paint off. I'm quite sure that won't happen with this stuff. Also, I can use a little more aggressive cleaners to clean it.

Ken

 

[tpenfield]

The Rust Seal stuff is primarily geared towards the restoration of iron-based metals (steel). I have not seen anything in their product information that is specific to aluminum in an underwater application.

So, you are sort of going alone on this one. Not sure anyone on the forum could specifically answer your question. Let us know how it goes.

FWIW - I used Interlux Interprotect EP2000 on my outdrives, eventhough it is primarily used as a barrier coat for fiberglass and was specifically targeted as an outdrive paint. However, the paint was recommended for use on aluminum as an adhesive primer and is an epoxy-based paint. So far (3 years) it has worked great.

It just seems that the base paint that you have chosen is more of a rust sealer rather than an aluminum primer. It probably won't harm the outdrive, but who's to say it will protect it either :noidea:

 

[1979 Quartermasters]

Thanks again Ted.

 

[1979 Quartermasters]

Well I don't know if anybody other than Ted cares about my little adventure, but I will share my progress anyway.

I used a chemical stripper and it got most of the many layers of paint off. I then used a brass wire wheel to take the remainder of the material off. I know your not supposed to use a steel wire brush on aluminum, but the brass one is ok, right?



Ken

 

[StingrayMike]

that's shiny!!
Just remember as soon as the aluminum is bare, its starts to get corrosion, so if it sets, you should lightly resand, wipe down, then prime.

I know that steel wire wheels are bad, but in my experience, brass worked. I redid my entire outdrive as well, all down to bare metal using brass wire wheels and sand paper, didn't have any paint issues for 3 years (sold the boat, so not sure after that)

 

[Scott Danforth]

Use a proper zinc chromate etching primer

POR15 doesnt stick to aluminum, why would a knock off of it stick to aluminum

 

[1979 Quartermasters]

Thanks Scott. The fellow at the paint store said if prepared properly it would stick and also it says on the can that it is for aluminum. I have been back and forth since I bought this stuff and can't make up my mind whether I'm going to use it. I think I'm off to get proper painting supplies today.

Ken

 

[Scott Danforth]

I had POR 15 come off in sheets and it was properly prepped by blasting.

good luck.

the best thing out there is a zinc chromate primer. even the Moeller rattle cans work better than POR 15 on aluminum. we use a 2-part low VOC metal-lock primer at work for aluminum

 

[1979 Quartermasters]

Ok, I'm convinced. I don't have the experience or tools to use those 2 part systems. Rattle cans it is. Is it any help to apply clear coat out of a rattle can?

Ken

 

[Scott Danforth]

most moeler kits come with primer, color coat and clear top coat. it doesnt hurt.... it also doesnt help other than to make it shiney

my suggestion

zinc chromate primer (either spray on or brush on) this could be moeller, interlux, SEM, PPG, axalta or other. this will stick to the aluminum. these primers are self-etching
primer surfacer/sealant (either spray on or brush on) - this will seal the zinc primer and make a good base for top coat
rustoleum paint with hardener (either spray on or brush on) - this is a cheap, and robust top coat

 

[1979 Quartermasters]

Thanks Scott.

Ken

 

[Scott Danforth]

BTW, rustoleum black is the same color as PPG's 9000 black which is Mercruy Phantom black

 

[1979 Quartermasters]

:thumb:

 

[tpenfield]

Zinc Chromate is the way to go, some of the stuff at the marine stores is Zinc phosphate . . . not as good.

 

[1979 Quartermasters]

Thx. In that kit I bought, there is an etching liquid called Power Blast. Would it be a good idea to use that before the Zinc Chromate?