Prop Paint not staying on?

[Expidia]

Had my aluminum prop redone 2 weeks ago. They rushed it through for me at my request, so maybe they did not prepare the surface with the proper primer.

I used it the very next day so even if it was done right I might not have given it enough time to dry.

Mostly used in fresh water.

Either way, when I used to scrape the old prop every now and then I'd sand it to feather the edges and since the spots are bare aluminum I sprayed it first with a little grey automotive primer and after it dried I followed by some matching black automotive spray and it used to work well with my other OEM prop.

Maybe this new Michigan Wheel prop's metal is a different composition cause I can't keep the sprayed on paint on the back of the prop to adhere very well. I did spray it again the night before my last trip the next day and some bare patches are back again.

So I'm guessing my variables are:

1. I need to probably use some type of marine primer for aluminum first

2. I also need to use some type of marine black paint. Maybe, pick up a spray can from the Merc dealer.

3. Allow more time for the touch up to dry before I use it.

Does someone make like a rustoleum product for aluminum that is all in one in the spray can and no need for the primer first?

Any thoughts on how I should be doing a touch up and have the paint stay on the prop?

Note: I have to say iboat's ad's work pretty good. Now that I mentioned the word rustoleum I noticed on the right side of my screen a link to Rustoleums new universal spray paint. Doesn't sound like the stuff I'm looking for but that's pretty good targeted marketing IMO. Says Ads by Google, no wonder why Google's stock price is so high!

Thx

 

[xxxflhrci]

Re: Prop Paint not staying on?

Back when I was using an aluminum prop, I just sprayed it with Walmart 96 cent a can gloss black every now and then to make it black and never really worried about it.

 

[Robj]

Re: Prop Paint not staying on?

I don't think it is a problem with the paint sticking. I think it is just getting worn off from the water and any suspended particles, such as silt in the water. The wear is worse on the leading edge, which is due to the prop cutting through the water. Regardless what paint you use, it will probably wear off the same way. Just the nature of the beast.

Have a great day,

Rob.

 

[Expidia]

Re: Prop Paint not staying on?

Yes, I've seen the leading edge type wear. Especially from the muddy silty Hudson River I frequent.

But this is on the back side of the prop where large areas just peeled off.

I'm sure there has to be some type of primer because paint does not stick to metal on it's own unless it's a special spray like rustoleum.

 

[pduquette]

Re: Prop Paint not staying on?

I've redone my OB with Tempo antifouling paint and primer - specialy made for below water . I didn't do my prop tho. has held up good so far on the L.U. But at $8.00 a can .......

 

[hibbert6]

Re: Prop Paint not staying on?

I had something aluminum to paint recently and the guy at the paint store said to be sure to use an oil-based primer because it sticks to anything. I always thought that all aeresol paints were oil-based, but not so any more. Apparently all Rustoleum products are oil based, though, so try a can of their primer and see if it works. $4.66 at Home Depot.

Dave

 

[Expidia]

Re: Prop Paint not staying on?

Thx for those responses. The only info I found was about retouching Aluminum air plane props.

They say not to use steel wool to feather the painted edges as steel wool's particles can cause a galvanic response with the aluminum.

They say to use aluminum oxide sandpaper instead.

But air plane props don't spend their much of their life under water.

What I do remember is when I wanted to paint my aluminum storm windows and I had to first coat them with this aluminum clear primer solution. The paint was the same as I used on the house which was water based.

I think I'll call the place who painted the prop after they repaired it and see what they use for a primer or if they just spray it with an oil base paint. For only $28 to straighten it my guess is they have a one step spray.

Another article I read said allow 48 hours to dry for the Aluminum airplane prop retouch. I was in the water again before that, so I don't blame the prop repair places paint job.

Even on an auto you can't spay paint on it without using a primer cause paint does not stick to bare metal.

 

[nlain]

Re: Prop Paint not staying on?

On aluminum you are supposed to use an etching primer, you can by that in a spray can at the auto parts house, up until recently I had always used zinc chromate primer only, now I use both before painting with Merc Phantom Black, all spray can, it seems to stay pretty well for me, as long as I stay away from the mud and sand. I always try and give it several days to dry.

 

[Expidia]

Re: Prop Paint not staying on?

Thx for all the responses . . .

I actually picked up 2 cans of Rustoleum gloss black in Home Depot (about $4 a can as the other poster said).
But they don't carry any etching products to use as a primer.

He said the only one they have actually gets mixed in with the paint.

He also said nothing they have, even the Rustoleum product would stay on the prop very well since it's underwater and the silt strips it right off. He said I'd be better off buying the marine grade stuff from a local marina.

I checked online and I see the Tempo products available. I also see the Quick/Silver Mercury cans at $12.99 at West

Quickslilver also makes a grey primer too.

Geez at those prices I'm picturing those long sweeping over spray strokes and watching 90% of the paint hitting the ground . . . Yikes!

I think I'm going to try this posters suggestion "On aluminum you are supposed to use an etching primer, you can by that in a spray can at the auto parts house, up until recently I had always used zinc chromate primer only, now I use both before painting with Merc Phantom Black, all spray can".

Although I did read an article where when they touched up aluminum props on airplanes it didn't take much paint to throw it off balance and cause vibrations.

I'll pick up a can of etching primer at an auto store and a can of the Quicksilver Phantom black and see how it goes before I use the extra layer of zinc chromate.

I called my boat dealer and he said he has the Quicksilver cans, but I know if I drive there it will be some knock off brand. If it is the Quicksilver they probably get $19.99 a can!

 

[lots of boats]

Re: Prop Paint not staying on?

Hi.

Paint and aluminum don't get along very well because nothing ordinary sticks well to oxidized aluminum, and aluminum oxidizes almost instantly. Thats why you etch aluminum with various compounds which all do about the same thing as diluted HCL, or muriatic (sp?) acid, which loves to dissolve all types of aluminum. So you etch it, prime it with something that has no copper in it and paint it, then the silt takes some of it off but, what really kills it are the exploding and imploding bubbles, cavitation, on one side of the prop, pressure on the other side Can't avoid it. I used to send my props out for rebuild, and I would tell them not to paint them, for two reasons. One is that with the paint on you can't see whether the weld is full of bubbles, the other is that the paint gets into those bubbles and makes the second rebuild more difficult. I think that the paint that really stick to aluminum is given an opposite charge from whatever it is supposed to stick to when it is sprayed on, but I'm not sure about that. Cheers.

 

[Expidia]

Re: Prop Paint not staying on?

Thx for that explanation. You are right and now I see why the other poster etched his prop first. I never had as big a paint sticking problem until both props were rebuilt.

So from what you are saying it's because they are already oxidizing and then they are just hitting with black Rustoleum.

I already picked a can of Mercury Quicksilver Black and the same for their Grey primer.

I actually thought about calling the rebuild place and asking them not to paint it cause I know their cob job paint job would come off anyway and it makes sense that it's the oxidation process at work.

I'll pick up some etching stuff. Does this come in a spray can too?
Maybe that was etching stuff that I had to paint onto my auminum window frames before I painted them. It was a clear liquid.

The guy at the Marina shop said just rough it up with some sandpaper first.

Thx for this great explanation

 

[nlain]

Re: Prop Paint not staying on?

It comes in a spray can, check the link below.



http://www.autozone.com/Ntt,etching...m;jsessionid=5E8B6118851D4DCCC2A85BDF23BA8AAD

 

[Expidia]

Re: Prop Paint not staying on?

It comes in a spray can, check the link below.



http://www.autozone.com/Ntt,etching...m;jsessionid=5E8B6118851D4DCCC2A85BDF23BA8AAD

So that looks like it's an all in one solution. Etcher plus "Primer". I might as well return that $12.99 can of Mercury Quicksilver primer . . . right?

 

[nlain]

Re: Prop Paint not staying on?

Automotive bodyshops actually put the etching primer, then primer, then paint. I just painted my lower unit after skeg repair, had some other paint damage so I sanded the whole thing, blew it off with compressed air, wipe down with mineral spirits, blew it off again and started spraying the etching primer, let it dry, put on a coat of zinc chromate primer, then Merc Phantom Black. I want to say that there are instructions on the Merc website on how to paint an outdrive.

 

[Expidia]

Re: Prop Paint not staying on?

Automotive bodyshops actually put the etching primer, then primer, then paint. I just painted my lower unit after skeg repair, had some other paint damage so I sanded the whole thing, blew it off with compressed air, wipe down with mineral spirits, blew it off again and started spraying the etching primer, let it dry, put on a coat of zinc chromate primer, then Merc Phantom Black. I want to say that there are instructions on the Merc website on how to paint an outdrive.

I'll swing by the auto supply store and pick up some etching primer and also the Zinc Chromate primer like some of the other posters are using too.

I have the Quicksilver Merc black in a spray can already.

Thx for these tips and pointing me to the instructions on Merc's site.

Funny, I had to go out to the garage an hour ago and as I was walking by the boat I noticed "all" the paint that I touched up after sanding the back side of the prop is all off again!

Gonna etch the bejeezes out of that sucker now