# Rattle Can or Brush on Self Etching Primer?



## FuzzyGrub (Apr 2, 2012)

I have looked at paints in a couple of hardware stores and have not found any primers that say "self etching". Many say for metal, but don't mention self etching, and claim "rust" preventatives, so suspect they are just for steel. I can get zinc chromate (green stuff) from a marine store, but rather expensive. Surfing Krylon and Rustoleum websites hasn't helped, outside of showing a pic of what the hardware stores didn't have. . Anyone find a reasonable self-etch primer? Does most Wally Worlds carry it?


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## kfa4303 (Apr 2, 2012)

Hi FuzzyGurb. I'm surprised you're having a hard time finding it. It's almost always sold as an aerosol and most auto stores and/or Lowes/HD carry it in stock in the spray paint section of the store. Be sure you're looking for Zinc-Chromate Self-Etching primer. Rutoleum makes a version as do many other companies, but the rand is unimportant. Here's a pic.


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## FuzzyGrub (Apr 2, 2012)

I only stopped at two, usually well stocked, local h/w stores. I haven't tried the large chains (further away) or local auto parts. 

Online, here is what I found for HD: https://www.homedepot.com/Paint-Pri...splay?catalogId=10053&langId=-1&storeId=10051


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## Jdholmes (Apr 2, 2012)

Don't trust the online store for HD...they often don't have the full selection on the website.

Home Depot and Lowes carry it at any of them I have been to. I got mine at Walmart for cheaper, though...I believe it was 4.77 a can.

At Walmart most of the spray paint is kept in the paint dept locked up - it was not with those it was actually with the auto body stuff ie fiberglass repair etc.


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## Proyotehunter (Apr 2, 2012)

That primer works wonders. You can get it at Home Depot with 10% military discount and it comes out cheaper than WM.


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## Jdholmes (Apr 2, 2012)

Or you can get them to price match Walmart and then beat that price by ten percent....with their match and beat policy it should make it even better.


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## PSG-1 (Apr 2, 2012)

The Zinc Chromate made by moeller is probably the best quality out of all the self-etching primers. 

Zinc Chromate is what the manufacturers use when they paint aluminum boats, to promote paint adhesion.


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## FuzzyGrub (Apr 2, 2012)

PSG-1 said:


> The Zinc Chromate made by moeller is probably the best quality out of all the self-etching primers.
> 
> Zinc Chromate is what the manufacturers use when they paint aluminum boats, to promote paint adhesion.



Assume that means, that "self-etching" doesn't mean zinc chromate. Sounds like I have to bring a magnifying glass to read ingredients! 

The Zinc Chromate that I have used in the past, outside of the cost, has held up well on intake manifolds, outdrive, and outboard legs. never any chipping or peeling.


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## FuzzyGrub (Apr 2, 2012)

I see that Autozone carries the Rust-oleum self etching, but the MSDS does not show zinc chromate. It does have a zinc phosphate. The pro version, I linked to above, MSDS doesn't show zinc chromate or any zinc compound.


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## PSG-1 (Apr 2, 2012)

I have used the Rust-O-Leum self-etching primer on a few things, like the aluminum frame for the windshield in my boat, and it has held up, no paint flaking, etc.

But as far as metal that would be in constant contact with the water, I'd spend the extra money and get the zinc chromate. When I re-painted my jetboat about 2 years ago, I bought a quart of the interlux zinc chromate, it was a 2-part mix, and I sprayed it on the boat with the HVLP.

It's important to remember not to put on TOO thick of a layer of primer when doing aluminum, what you really need is a 'fog coat' that faintly covers the aluminum, and feels rough to the touch...this rough texture provides the 'tooth' necessary for good adhesion of paint.


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## Gramps50 (Apr 2, 2012)

I get mine the Restoleum brand at my local WM, it's not in the paint dept but in Automotive with the body repair stuff.


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## FuzzyGrub (Apr 3, 2012)

This will be for new aluminum on interior:







I will be painting it a similiar color to the existing. Something like Rust-oleum Flat Camo Khaki. A light gray primer might be better than a dark green one. I want to get it primed and a couple of coats on it before putting in front and rear decks. 

I plan to sand and wipe down the new alum before priming. I read a number of threads where a vinager solution is used for final wipe down. I assume this is a pre-etching process. Should I do this? If so, what concentration of vinager to water? and is there a amount of time the paint has to go on after the application?


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## PSG-1 (Apr 3, 2012)

Not sure about vinegar. 

I've always used a diluted phosphoric acid to etch, then a good rinse with water. The phosphoric acid chemically changes the surface from aluminum oxide, to aluminum phosphate, and neutralizes the oxidation process. 

If you use the phosphoric acid to etch, you won't even need to do any sanding....which, BTW, sandpaper is made from aluminum oxide, the one thing that interferes with welding, or painting aluminum.


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## FuzzyGrub (Apr 3, 2012)

PSG-1 said:


> , BTW, sandpaper is made from aluminum oxide, the one thing that interferes with welding, or painting aluminum.



Excuse my ignorance on painting aluminum, but are you saying you recommend NOT sanding the aluminum? or was it to absolutly make sure you have cleaned it very well after doing so?


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## kfa4303 (Apr 3, 2012)

Hello again all. To answer a few of your questions; you can use lots of different products to wipe down the hull in prep for primer. Tri-Sodium Phospate (TSP), Acetone, 50/50 mix of water and white vinegar are all good choices and all being organic solvents, ultimately perform the same function of removing grease and other oils from the hull (organic chemistry 101: "like dissolves like"). Also, while it certainly won't hurt anything to sand the new aluminum in preparation for primer and paint, the Zinc Chromate SELF ETCHING primer will do the job all on its own, hence the term "Self-Etching". ZC-SE primer is actually a dilute acid that eats tiny pits into the surface of the metal thus allowing better adhesion of primer and paint. A little goes a long way, so you only want/need a light dusting of primer on the bare metal. Cheers!


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## PSG-1 (Apr 3, 2012)

FuzzyGrub said:


> PSG-1 said:
> 
> 
> > , BTW, sandpaper is made from aluminum oxide, the one thing that interferes with welding, or painting aluminum.
> ...




No, I'm not saying you should avoid sanding. Just a reminder that the material used in sandpaper is the one thing that can cause problems with painting, so, you want to make sure you neutralize it with a good cleaning with a mild acid like vinegar, or phosphoric acid. But as I said, if you use the phosphoric acid, that will etch the metal well enough, you won't need to sand it.


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## PSG-1 (Apr 3, 2012)

kfa4303 said:


> ZC-SE primer is actually a dilute acid that eats tiny pits into the surface of the metal thus allowing better adhesion of primer and paint. A little goes a long way, so you only want/need a light dusting of primer on the bare metal. Cheers!



Yep, like I said, basically just a 'fog coat' of primer, not too thick. Leaving it thin gives the surface the proper 'tooth' for good paint adhesion.


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## FuzzyGrub (Apr 3, 2012)

I picked up the Rust-oleum self etch primer and camo paint at walmart. The primer was hiding in the auto section. 

Well I have to sand the 5200 so will lightly sand all the new alum. A good wipedown and can prime and paint.


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## tdub (Apr 3, 2012)

Use soap with a scotch brite pad, then rinse. After it has dried wipe it down with straight vinegar, let it dry and paint. After painting pull your hull into full sun and let it bake on(I used hunter specialties OD green). That is what I did and no paint has come off yet after almost 3 yrs.


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## BackwaterNH (Apr 5, 2012)

FYI I found the RustOleum etching primer @ Aubuchon Hardware. I've never used it before now, but it appears to work great. As for sanding aluminum I use scotch brite pads. They scuff the surface nicely. That's my .02


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