What kind of primer for bare aluminum?

[CPM]

Hello folks.
I have my rescued jon boat stripped and waiting for refinishing.
There is some of the factory finish left around rivets and inaccessible crevices.
I would like to spray both the primer and topcoat.

I've done quite a bit of searching here and elsewhere and it seems to come down to 3 options; epoxy, self-etch and zinc chromate.
Any info that I can find from the forum search seems to turn up threads that are fairly old so I suspect their may be new info on the market.
I think self-etch is out because it may lift whatever paint is still left.

The boat will only be used in fresh water and trailer kept.

I don't want to imply that cost isn't an issue but I like to spend my money and labor once. So quality and performance is my main concern.

Please advise.

 

[AShipShow]

Good quality zinc-chromate is the best option however hard to get for a diy person since chromate will give your kids 7 extra fingers... That being said you can still get it in small quantities, and you may be able to bribe your sherwin williams to get you some... Not saying other things won't work, but zinc chromate is the industry standard for priming aluminum...

 

[CPM]

Thank you. I have a full face respirator and my reproductive days are behind me.
What would be the next best option if I can't get the zinc chromate? Epoxy?
Am I correct that the self-etch may lift the little bit of paint still there?

 

[gm280]

Thank you. I have a full face respirator and my reproductive days are behind me.
What would be the next best option if I can't get the zinc chromate? Epoxy?
Am I correct that the self-etch may lift the little bit of paint still there?

Zinc chromate is the best. The military still uses it today for anything being paint that is aluminum. And that is because it does what it is suppose to do very well. However, there are other methods that work well also. Either of your options will work. And to the best of my knowledge, self etching primers won't lift old paint or primer. That is if they are solidly adhered to the surface already. Any slight peeling should be faired out before priming.

Just remember this, the prep work is the absolute best way to have an amazing finish. You can't do a so so prep job and think the primer and top paint will hind anything. So if you are looking for a really nice finish, now is the time to do the real work before shooting even the primer coat...

 

[archbuilder]

I use Dupont Varapirme, you can get it at automotive paint supplies, works excellent. That being said, depends on where you live. I suspect that in some states you won't be able to buy it unless you are a body shop. It is fairly pricey, but stick tenaciously. I use automotive paints over the top of it, but suspect it will work with most oil base paints.

 

[archbuilder]

by the way it is self etching, never had a problem with over spray it lifting old adjesent paint, but there is always a first! You only put it on areas that are bear, then seal or prime over that. You can also spray top coat over it in most cases.

 

[CPM]

Thanks for the replies.
I tried my best to talk a local industrial marine coatings Sherwin Williams into selling me zinc chromate but I got the brush-off.
I ended up using Rustolium self-etch primer with pretty good effect. Even though I put quite a bit of effort into removing most all of the factory coating, leaving behind only what refused to come off, the primer did end up lifting just very small amounts of the factory finish that was left behind. I solved that by hitting those spots with a small wire brush and getting bare aluminum in those spots this time. I spot primed those areas and am now waiting for the rain to stop so I can do my top coats. I hope I don't regret it but I plan on using Rustolium "professional" oil base. Hunter Green.
I'm leaving the underside of the hull bare aluminum since it'll see fresh water only. That's okay isn't it? Bare aluminum in fresh water?