Paint for aluminum?


Well-Known Member
It seems paint does't like to adhere well to aluminum. How does one best go about painting it so that the paint sticks and holds up? Project in mind is that old Herters model 39 powder measure I asked about reservoirs for. Our local farm store hassome implement paint that looks pretty close to the original shade of green.


Well-Known Member
He means acid etch the surface. A good prep for etching aluminum is phosphoric acid. You can buy it in any autobody supply house. Not dangerous to use. But it does have a funky smell that if it gets in your nose will stay there for rest of the day. Do it outside. It is also a great product for removing surface rust without hurting the base metal or any paint. I've used it for years to de-rust motorcycle gas tanks.


Notorious member
Naval Jelly is no good for Aluminum. Use Ospho or a self-etching primer for steel, available in rattle cans and works on Al too. Might be able to use CLR to etch, IIRC it contains mostly phosphoric acid, but double check that.

The best method to prepare aluminum for paint by far is to anodize it. Anodizing passivates the surface so it won't ever corrode and bubble under the paint and provides a very toothy surface for paint adhesion.

If you don't anodize, acid etch and paint then seal the paint with car wax and buff so the paint pores are sealed and the metal won't corrode under the paint as quickly.
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Well-Known Member
Is this what we used to call naval jelly?
There used to be a product made by the same company called Aluminum Jelly. It was basically phos acid in a jelly form. Have not had a need since I bought a gallon of phos acid. Not sure if they still make it. Google it and you'll find out.


Halcyon member
I use phosphoric acid for cleaning/sharpening/reconditioning metal hand files.
The cheapest way to buy it, is go to a farm store and ask for Milkstone remover. It's fairly high concentrate, you will probably will need to dilute it for etching alum. You will probably want to do a neutralizer bath (baking soda water) afterward.


SE Kansas
I've had good results from Cerakote; last project was a 22 receiver.


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West Central AR
You know what has lots of phosphoric acid in it and eats everything eventually ? See urban legends also .
Coke a cola .


North Central Arkansas
I've had good results from Cerakote; last project was a 22 receiver.
I'm sold on Cerakote. Jobbed out my SS Marlin 1894 in dark grey. Place called Fit 4 Duty, in Kansas, IIRC. Holds up really well. That's been over twenty years ago. I don't think they're still in business.

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Tomme boy

Well-Known Member
Don't use naval jelly. That is paint stripper.. Go to an auto body supply house and get some Dupont 225 and 226. one is a cleaner and the other is the etching compound. This was the #'s when I sold it years ago. They may have changed them since then. If you really want the paint to stick use the 615. It is a self etching primer that works better than everything else out there. I have tried them all when it comes to autobody use.


Resident Half Fast Machinist
Getting paint to stick to aluminum was one of the first hurdles that needed to be overcome by the aircraft industry when it transitioned to aluminum skin aircraft.

Anything we make from aluminum that needs to have any finish other than natural we get ceramic coated. A friend of mine runs a metal finish shop, he does it in all sorts of colors, we usually stick to black. Once done it's almost impossible to wear thru, we've had it done to machine tools and stuff subject to wear and it has held up really well. If anyone is interested I'll send you his contact info.