Best way to paint aluminum?

Kevin Q

Kevin Q

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I'm getting ready to paint a bunch of new parts including Savvy Sliders and bumper along with UCF rear bumper. I wanted to hear best practices for DIY. I already bought the Rust-Oleam Self Etching primer. I sanded the UCF bumper and just need to grind down a rough edge. Next I was going to clean with Acetone. 3-4 layers of primer, 3-4 layer of Satin black.
 
Clean/scuff it up with a maroon Scotch Brite pad, wash it clean with some sort of degreaser(aluminum is very dirty material), then wipe it down with alcohol or acetone before applying your primer. Once the primers down its just a matter or spraying your top coat.
 
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Being that I work in aviation, i'd go the zinc chromate route if I was topcoating bare aluminum.

https://www.amazon.com/dp/B000N8LR24/?tag=wranglerorg-20

One thing to note (at least I have to down here in humid Texas) once you prep the aluminum you shouldn't dilly dally around before putting the primer on. Like don't let it sit overnight and spray first thing in the morning, you've already started contaminating the surface by letting it sit. Again, another extreme aviation thing but still.
 
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I agree. As soon as you can put a coat of self etching primer. I like the weld-thru primer as it really bites into the metal.
 
Thanks for the tips so far guys. Being in the industrial safety field I am thinking that I will skip the ZC Primer.

@jeepins Cool picture with the Warthog. They used to be stationed at the Willow Grove Naval Air Base near my old house. They would fly very low over our house all the time. Really cool to see.
 
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jeepins said:
Being that I work in aviation, i'd go the zinc chromate route if I was topcoating bare aluminum.

https://www.amazon.com/dp/B000N8LR24/?tag=wranglerorg-20

One thing to note (at least I have to down here in humid Texas) once you prep the aluminum you shouldn't dilly dally around before putting the primer on. Like don't let it sit overnight and spray first thing in the morning, you've already started contaminating the surface by letting it sit. Again, another extreme aviation thing but still.
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I second the zinc chromate route.
 
kmq102 said:
I'm getting ready to paint a bunch of new parts including Savvy Sliders and bumper along with UCF rear bumper. I wanted to hear best practices for DIY. I already bought the Rust-Oleam Self Etching primer. I sanded the UCF bumper and just need to grind down a rough edge. Next I was going to clean with Acetone. 3-4 layers of primer, 3-4 layer of Satin black.
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Follow the directions on the product you are using. Aluminum forms a protective layer of aluminum oxide almost instantly upon exposure to the normal atmosphere. The thicker that layer gets, the more it becomes a bond breaker.
Prep and then scuff the aluminum right before you hit it with the primer.

Ease all the edges with a file or sandpaper. That will help the paint roll around the edge better and not give it a place to start peeling.

Aluminum is not really a dirty metal. The aluminum oxide just shows up as very dark gray to black when it is rubbed off due to the very fine particle size.

Do not spray too dry, everyone sprays too dry because they are afraid of runs and then the paint looks like crap. Also with self etching primers, you need to get a heavy enough layer that etching can happen. If it dries too fast from being too thin, it won't etch.
 
jeepins said:
Being that I work in aviation, i'd go the zinc chromate route if I was topcoating bare aluminum.

https://www.amazon.com/dp/B000N8LR24/?tag=wranglerorg-20

One thing to note (at least I have to down here in humid Texas) once you prep the aluminum you shouldn't dilly dally around before putting the primer on. Like don't let it sit overnight and spray first thing in the morning, you've already started contaminating the surface by letting it sit. Again, another extreme aviation thing but still.
Click to expand...
We don't paint aluminum. We don't even let our automotive painter paint aluminum. We take all of our aluminum down and have a ZC primer put on at the powder coat shop.
 
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2K epoxy does a good job of sealing followed by base and clear.

Sliders 1.jpg


sliders 2.jpg


Edit: get some tack cloths so you can lightly wipe it down between each coat.
 
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mrblaine said:
Follow the directions on the product you are using. Aluminum forms a protective layer of aluminum oxide almost instantly upon exposure to the normal atmosphere. The thicker that layer gets, the more it becomes a bond breaker.
Prep and then scuff the aluminum right before you hit it with the primer.

Ease all the edges with a file or sandpaper. That will help the paint roll around the edge better and not give it a place to start peeling.

Aluminum is not really a dirty metal. The aluminum oxide just shows up as very dark gray to black when it is rubbed off due to the very fine particle size.

Do not spray too dry, everyone sprays too dry because they are afraid of runs and then the paint looks like crap. Also with self etching primers, you need to get a heavy enough layer that etching can happen. If it dries too fast from being too thin, it won't etch.
Click to expand...
Can you explain what you mean by "do not spray too dry". I've seen this said in other places but I'm not sure what is meant by it.
 
Wesrj86 said:
Can you explain what you mean by "do not spray too dry". I've seen this said in other places but I'm not sure what is meant by it.
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Don't be afraid to lay down the paint wet after your first coat otherwise it'll look grainy. Run about 25psi with a gun with 1/4 overlap for three coats. Harder to do with a can. Probably more coats. Doesn't have the fan that a gun has. This skid was done with rustoleum in a quart container.

20200714_021215.jpg


20200714_033533.jpg


20200714_033431.jpg
 
IMG_2932[1].JPG


Mocked up the bumper just to check fit. Will drill out the holes and paint the cross member. Tomorrow I'll paint the steel part and see how that goes. If all is good I'll carefully paint the Aluminum shell.
 
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Dry just means not enough product is laid down to be able to flow together. There will be a wet film thickness listed, find the Tech Data Sheet online if it is not shown on the product. You can get a mil gage at most paint stores for like 5 bucks if you are unfamiliar with finishing. Good thing to learn on, you'll recognize the "look" of 6 mil vs 10 mil pretty quick.

As Blaine stated follow the specific instructions for that product. Finish has it's own schedule and it doesn't care a bit about yours. They will vary.


You don't need more primer than is required to give you a smooth base. It's goal in life is to get the base material in a condition to accept a top coat and that's pretty much it.

And as stated above, clean between each coat, dust will build up in corners and ruin your day as you watch it land in your last pass.

My 2c.
 
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As is usually the story of my life...2 steps forward, 1 step back. Today I tried to mask off the bumper and paint the D rings body color. The spray can was very different and I mistakenly didn't trial it. First spray went on heavy and sagged. I tried to wipe off but it is messy. Should I let it set for 24 hours then sand and start over?
 
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