Painting Aluminum

TantoTrailers

Well-known member
Looking for opinions here. What is the best combination of primer paint and coat for aluminum parts that are going to get some love taps from gravel and small rocks coming off my tires? My fenders and tongue channels are alum and I painted them myself but they took a beating on a recent trip. Is there some paint that is more flexible like plastidip? I want a glossy finish to match my diamond plate and doors but I know I’m being picky. Any help would be greatly appreciated. I’m not trying to be a pavement princess and I know some battle scars are cool but my OCD is going nuts with the dings when the rest of it looks great.
 

F350joe

Adventurer
Rustoleum enamel has been impressive for me, the spray cans are kinda idiot proof too. I painted my flatbed and a few boat parts with it, it’s tough. Krylon is also very tough but has a more rubbery texture. As you probably know, you need an aluminum primer, and need to scuff it up pretty good. Some sort of rhino liner type paint will work but is more expensive and I don’t know how it works on aluminum.


 
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Vandit

Observer
As you probably know, you need an aluminum primer, and need to scuff it up pretty good.

👆 x2

I've painted quite a bit of aluminum lately and the Rusto Pro Series Aluminum Primer that F350joe mentioned has worked out great for me too. I scuff everything first with 80 or 100 grit then blow it off with air. Wipe down thoroughly with acetone or something like Duplicolor degreaser/cleaner. Then hit it with a tack cloth right before hitting it with the primer. I followed the directions on the can closely and the adhesion has always been good and has always taken the topcoat nicely.

After you've primed you can really topcoat with whatever you want, but if you want a nice, durable, gloss or semi-gloss finish it's going to be hard to beat Rustoleum Oil Based that comes in quarts (gallons too if you need a lot). It's oil, but because it's oil it levels out really nicely (but be careful if painting vertically because it will sag if the coat is too thick) and leaves a smooth, really durable finish that's easily washed or wiped down. You can get it at any of the big box stores and it's cheap.

It's been my experience that the Rusto oil based resists scratches and chips really well provided you give it the full recommended cure time before beating it up. However, if you do get deep scratches or chips you will see any touch ups you try to do. If you plan on doing regular touch ups then I'd probably recommend using some sort of spray. Rusto also makes a "professional" grade spray in gloss black (comes in a silver can like the alu primer) which is also pretty good, but not as durable in my experience as what comes in the quarts.

If you end up using something else that works out well be sure to let us know. Good luck!
 

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TantoTrailers

Well-known member
So Rustoleum enamel is what I have used with both primer and without and the primer does help but its not like the pieces that were done at the manufacturer. Im debating just taking these parts to a shop to have powder coated cause I truly hate paint....not my strong suit. I can build it to last through whatever I can toss at it but I cant paint it that way haha. Im also going to rig up a nice rock guard for the truck when going off road.
 

Vandit

Observer
I agree. Any DIY paint job is certainly going to be less durable. It just can't stand up to the industrial, epoxy, or baked on coatings that the manufacturers put on. If you have the option to powder coat then that should provide a nice maintenance free finish for a few years.

If you decide that durability is more important than having a smooth glossy finish then you could look at raptor liner. I got a few DIY kits of it and lined the rockers and fiberglass high top on my van. I've been very, very happy with the durability. After some tedious masking and proper prep it was actually really easy to apply and I'm happy with the final result. So far it has been totally scratch and chip resistant after 18 months. The only downside for your application would be that it has a texture and is not a glossy finish. But with everything, there's trade-offs.
 

rlrenz

Explorer
One ambulance manufacturer (Crestline) as adopted powder coating for their body panels. Probably a little overkill for our projects, though....
 

TantoTrailers

Well-known member
Trying to find a good powdercoater who isn't charging an arm + leg around me is not easy! Seems like everyone is high end around here...I live 40 mins west of Chicago so if anyone has a hookup let me know!
 

Third

Member
For smaller parts, you can always purchase an old oven from Craigslist, etc.

Fire off your own powdercoating in the back yard.

*you don't want to use the wife kitchen oven, trust me ;)
 

shade

Well-known member
Have you considered spray-on Monstaliner? It's a durable coating that should work well for your application, and you can re-apply as needed. I don't see aluminum prep mentioned specifically on their installation guide, so you'd probably want to investigate that further.

The main downside to using this type of coating is that it's a pain to deal with if you need to weld after application.
 
Spraymax 2k rattle cans are awesome. I’d start with their epoxy primer then their “hot rod black” and finish with the “clear glamour.” You’ll be about $60 in the three cans but it’s cheaper than a gun and compressor. If you have extra clear it’s also really great for restoring your headlights. Wet sand with 600 then 1000 and then hit them with a couple coats of the clear.
 

Alloy

Well-known member
Anodizing will be the most durable.

Don't use any kind of rubberized coating. It traps moisture and will cause the aluminum to corrode.

Powdercoating is durable but touching it up later is difficult.

An industrial paint system with an epoxy primer is easier to repair but it will cost more.
 

86scotty

Explorer
Because no one has I'll go ahead and mention Plasti-dip. Yes, it's cheap and yes it's cheap but it's very effective and looks good. More advantages are that it's 100% reversible if you decide to try something else and also you can touch it up very easily. It melts/sticks to itself.

I am curious about the corrosion statement above. It's not a problem I've had but I'm in a mild climate.
 

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rlrenz

Explorer
Because rubberized coatings do not chemically bond to the metal, moisture can get under the coatings. Years ago, Ford used to spray a rubber-based sound deadener on thebottom of their cars. Moisture would get under the coatings and form large, water-filled bags. The coating ensured corrosion. It is no longer used.
 

Alloy

Well-known member
When coatings fail moisture can become trapped under the coating.

Over time some water may evaporate but the impurities (salt) are left behind so the concentration of impurities increases which increases the corrosion.

With heavey coating it is difficult to see the areas of failure due to the thickness of the coating.

It will happen with powder coating but the coating will breakaway before the pitting gets really bad.

I've was on an aluminum boat that had moisture trapped under the 4yo truck bed liner on the deck. Owner didn't realized there was an issue until we cut an area open and he saw what was happening to the aluminum underneath.

I've seen an aluminum toolbox spayed all around and mounted on the front of an equipment trailer. The box looked good on the outside but on the inside there was holes from corrosion around the bottom. The aluminum was literally sitting in a salt bath.

Last year I saw a 3 year old truck box with a spray in liner that had to be redone. Instead of ordering trucks with a liner the dealer was spraying the liners. It took 5 days to strip the box. As the coating was peeled (it shouldn't) off one could see water under it but there was no corrosion. The saving factor in this case was the quality (type/prep/application) of the factory paint.
 
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