Best Primer and Paint for Stern Drive?

E

E350

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Really interesting article on galvanic corrosion:

https://en.wikipedia.org/w/index.php?title=Galvanic_corrosion&action=edit&section=5

Which made me smart enough (I think) not to prime the sandblasted bare aluminum bell housing and transom plate with red oxide primer!

So any suggestions on an aluminum primer?

https://www.amazon.com/gp/product/B006ZKMKSO/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

https://www.amazon.com/gp/product/B000GTIRAU/ref=ox_sc_act_title_1?smid=A3TXPR136ODXQ&psc=1

I will likely top coat it with Valspar Tractor and Implement Paint with Enamel Hardener which I am very familiar applying and have excellent results with outdoor equipment. But again, any suggestions?

https://www.amazon.com/Valspar-4432...MY49PJYGJQ67EKEMQ&qid=1560616929&s=automotive

https://www.amazon.com/Valspar-4625...2VTZVF1996PJ3JD36&qid=1560616966&s=automotive
 
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Searay240sd

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Google zinc phosphate primer. That's what I have used on my outdrive in bare spots and then coated it with outdrive paint. I never had an issue.
 
San_Diego_SeaRay

San_Diego_SeaRay

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People recommend zinc phosphate a lot, so I imagine it does a good job. However, I've had very good results with two part epoxy primer. I buy it on ebay (type keywords DTM EPOXY PRIMER). I buy the T-REX Speedkote stuff...cuz it's cheap. The stuff is awesome on bare metal, and does an incredible job of SEALING. Which is exactly what you want from your protective coating.
 
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Searay240sd

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That is the sea hawk paint that I have been using for years. I have 0 problems with it adhering to my bravo 3 drive. My boat stays in salt water for about 6 months. Great paint.
 
Scott Danforth

Scott Danforth

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moeller paints available right here on iBoats. order the zinc primer, order the top coats, best you can do with a rattle can
 
San_Diego_SeaRay

San_Diego_SeaRay

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E350 said:
San_Diego_SeaRay: I have never sprayed epoxy before, but I would like to try. You use the second one? Do your spray it? I so what size tip and do you thin it?

And what do you recommend for a top coat for aluminum like the stern drive?
Click to expand...

Yes. I use the 2nd one (link). But I'd bet the other one you linked to would work great as well.

For a top coat I used the Restoration Shop AU Acrylic Urethane Quart Kit from TCP Global. Again, because it was the cheapest. Mine was kind of a first time experiment, but it's holding up very well. I'm not a painter so looking back I made some mistakes. One mistake was that the primer sealer I used (that you linked to) is not meant to be sanded (despite the ebay description...primer sealers should not be sanded). It will gum up your sand paper. And all of the scratches will defeat the purpose of a sealer anyway. From what I understand you're supposed to apply a primer filler/surfacer afterward and then sand that down and remove the sealer imperfections that way.

Second mistake I made was not applying a few coats of Acrylic Urethane Clear Gloss. As it was, because the sealer couldn't be sanded and my gun was shooting it with a heavy orange peel texture (I used a 1.8mm tip - I should have thinned it but I didn't), the topcoat layed down with orange peel texture as well. I *think* a few coats of gloss on top of the top coat would have improved that. Again, I'm not a painter so I can't say for sure. Yes, you can thin the primer with the appropriate reducer that the ebay vendor also will sell ( SMR_0075 per the ebay description or they might recommend an alternative if you ask them). The Acrylic Urethane gets reduced w. a Urethane Reducer.

By the way, I should add that I painted a transom assembly, not a sterndrive. I still have to find the time to paint the sterndrive. I'm definitely going to use the same materials, just use the filler primer between the sealer and top coat next time. Probably will use a Urethane Primer like this one.
 
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E

E350

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Thanks Scott Danforth for your reply! San_Diego_SeaRay: I am pretty new to spraying with a gun too. But I've been using this gun with the 1.4 tip for everything and it lays down a smooth finish once you get it adjusted spraying on cardboard and get used to it. At $29 full price and less with a 20% off coupon, it is fantastic!
62381_W3.jpg

https://www.harborfreight.com/20-oz-...tor-62381.html

I have been winging it with how much thinner and hardener I mix in and was still having good results until I painted the bell housing last night. I always save the In-N-Out Burger paper cup which I mix the paint in to see how fast it sets up, and it is still liquid so I didn't put enough hardener in and I used too much thinner so now it will take a while for the paint to cure.

I ordered these measuring cups so I can be more consistent in my mixing:
71j85NvaUEL._AC_AA100_.jpg

https://www.amazon.com/gp/product/B0...3Q8UAUTT&psc=1
 
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San_Diego_SeaRay

San_Diego_SeaRay

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E350 said:
Thanks Scott Danforth for your reply! San_Diego_SeaRay: I am pretty new to spraying with a gun too...
Click to expand...

Well it sounds like you and I are pretty much like minded thinkers. I used the $10 Harbor Freight gun. I think it has a 1.8mm tip.

Regarding thinning, I see people recommend 5-10%. But then you watch a YouTube video and they thin it like 20%! In the fiberlgassing world, when you thin the resin too much, it makes it structurally weaker when it cures. Not sure if this extends into the epoxy/urethane paint world.

Adding too little hardner is not the worst mistake. I can top that. When I was spraying the top coats, I accidentally added the Epoxy hardener instead of the Urethane hardner for one batch. That was fun... :facepalm:

By the way, exactly what paint are you using?
 
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E350

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Top coat paint is Valspar Tractor and Implement paint black:



81zfvRGYJhL._SL1500_.jpg




https://www.amazon.com/Valspar-4432...MY49PJYGJQ67EKEMQ&qid=1560616929&s=automotive

With this as hardener (not sold in California, must buy on the web):

817fvY9HuEL._SL1500_.jpg


https://www.amazon.com/Valspar-4625...2VTZVF1996PJ3JD36&qid=1560616966&s=automotive

You are supposed to use VM&P Naptha for thinner but it is illegal in California (so I just ordered some on the web) and I used a substitute recommended by the paint store. My guess is that the substitute sucks. I have used Acetone as a thinner before for this paint and it worked fine. I probably should have used it yesterday instead of the recommended substitute.

It is 84 F so it is hardening nicely in full sun.

BTW, if I knew how to make the images smaller I would...

I will post up another thread on gelcoat/urethane or epoxy for deck restoration. I hope you will contribute.
 
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