NOT A PAINTER

[Amata Bene]

Hope everone had a good Thanksgiving.
Like the title says I know little to nothing about painting, most of my experience comes out of a rattle can. You can see in the pic what I'm going for. I just want a bright aluminum look not polished. I have decal the print shop made for the large flat area then a few coats of clear.

I painted painted the V-covers with a coat of self etching primer then 4 coats of Dupli-Color engine enamel with ceramic. This was a couple 3 weeks ago. Came to the shop today to get in some personal work while the sun was shinning and get home before 11++ pm. I thought all was going well till it wasn't. Started the sanding with 120 then 220 then final with 320. Notice on the first one the paint chipping/flaking off at the edges. Thought maybe the 320 was to aggressive to start so, I started the second one with 220 then the 320. Same thing.

What do I need to do to remedy this. Should I put them in the blast cabinet and start over with a different paint. Or, can I just use the same paint and do the sanding while it's a little soft not a 3-4 week cure time. Thanks for any advice.

 

[Syleng1]

Blast them clean and start over.
Use a primer made for aluminum like the green etching primer (light coat) allow to dry then a light coat of the paint you are using primer then the paint. All allowing to dry fully. Then sand off the spots you want with a fine sand paper. Then wait the recommended dry time for recoat. When that happens use an automotive engine clear over the tops.

This method has worked for me for years as I love that look. Just my 2 cents.

 

[ch1ll]

That sucks, looks good from a distance.
Did you wipe them down with a pre paint cleaner?

I agree with media blasting them, it will rough up the surface and give the primer something to stick to. Die-cast is way too smooth of a surface, even with self etching primer, then wipe down with self said pre paint cleaner.
Clear coat always turns yellowish cloudy on me after a while you may want to use a heat lamp to cure it.
And I would try using a piece of sandpaper glued to a block of wood instead of a sander.

When I paint, I use products all from the same manufacturer, cleaner, primer and paint. The only thing I hate more than painting is repainting after it doesn't turn out well the first time.

Didn't even know there was special primer for aluminum.

 

[Amata Bene]

That sucks, looks good from a distance.
Did you wipe them down with a pre paint cleaner?

I agree with media blasting them, it will rough up the surface and give the primer something to stick to. Die-cast is way too smooth of a surface, even with self etching primer, then wipe down with self said pre paint cleaner.
Clear coat always turns yellowish cloudy on me after a while you may want to use a heat lamp to cure it.
And I would try using a piece of sandpaper glued to a block of wood instead of a sander.

When I paint, I use products all from the same manufacturer, cleaner, primer and paint. The only thing I hate more than painting is repainting after it doesn't turn out well the first time.

Didn't even know there was special primer for aluminum.

I did blast them first. Got them used for like 75 or something, not real pricey, wasn't over a 100.

 

[Amata Bene]

Prep work was - Blasted then wiped down with acetone. Etching primer applied, 1 coat. Allowed to dry then the color was sprayed in lite coats and maybe 30 min between coats. Last coat was wet to the (my) eye.

 

[Amata Bene]

I don't recall if the primer was Duplicolor. I have to swing by the parts store and see. That could have been part of it. I've run into issues with combining different brands of rattle can paint before.

 

[ir3333]

a long time ago i sand blasted a pair of original valve covers to restore and sell. After thinking about whether or not some sand was trapped under the baffles they ended up in the scrap bin.

 

[jos51700]

It's the DA. It is pulling the paint off the corners as it rotates.

Hand sand, only, in the direction of the fins.

 

[4spdragtop]

I would start with finer sandpaper, 500? Maybe spray with adhesion promoter IF its hi temp?

 

[RustyRatRod]

I cannot STAND self etching primer. It's NEVER worked for me. I use Rustoleum filler primer now and have had good success.

 

[ch1ll]

Did you blast with glass beads or walnut shells?

Blast them with aluminum oxide or coal slag. That will rough up the surface, glass beads and the such, not much.

 

[RustyRatRod]

Did you blast with glass beads or walnut shells?

Blast them with aluminum oxide or coal slag. That will rough up the surface, glass beads and the such, not much.

I have GREAT luck with 80 grit glass bead. I've used it for a long time. I JUST got done blasting and painting all of Vixen's wheels and they turned out quite good for a old redneck.

 

[harrisonm]

It's the DA. It is pulling the paint off the corners as it rotates.

Hand sand, only, in the direction of the fins.

Totally agree with hand sanding. I did not see where he said he used a DA. Maybe I looked over it. But you are RIGHT! DA is NOT the way to go on a project like this.

I cannot STAND self etching primer. It's NEVER worked for me. I use Rustoleum filler primer now and have had good success.

I have never used self-etching primer. Every whole car paint job I have ever done was stripped to bare metal, bare metal scuffed with 80 grit on a DA and then a few coats of epoxy primer. Further coats of primer stick to scuffed/sanded primer just fine.

I have been powder coating for about 20 years now, and I have done a lot of valve covers, but in the past, I have done them with paint.
Here is how I would do it: Blast them down to bare aluminum. I use medium grit crushed glass. I have found that it leaves a perfect surface for paint or powder coating; not too rough and not too smooth. Then I would use the Rustoleum Automobile rattle can primer that @RustyRatRod mentioned. It is lacquer based, it fills blemished very well and it is easy to sand. I get it at Wal Mart for about $7 a can. It is pretty much the same as the lacquer base Duplicolor primer sold at car parts stores but a lot cheaper. I'd spray a light coat followed by two medium wet coats. I always wait at least 10 minutes between coats to give the solvents time to evaporate. Then I wait a few days to make absolutely sure all of the solvents have evaporated. Then I would wet sand the entire valve cover with 320, 400 and 600. Then, using 320 wet and a sanding block, I would sand all the primer off of the top of the fins, letters and that big rectangle in a straight linear fashion from end to end. Do not sand these places in a circle or side to side. If you do want paint on that rectangle, then sand it with 320, 400 and 600 like the rest of the valve cover. I would use a scotch brite pad to get in tight places like in between fins. You can use wet sandpaper that has been folded over several times to make it about 1/16 - 1/8" thick. Then paint them. Always make the first coat a light coat. Do NOT go for full coverage with the first coat. That is an invitation for runs. Then you can go with medium wet coats. Then I would let the paint dry for at least two days before sanding the tops of the fins etc. I would do that with 320 grit wet sandpaper on a sanding block going in straight lines end to end like mentioned before. By waiting several days and wet sanding in straight, end to end lines, I can pretty much guarantee you it will work out fine.
BTW, here is a pair of VCs I did for my Barracuda with powder.

 

[ir3333]

what don't you guys like about self etch primer? Isn't it for tiny exposed bare metal spots before basecoat or sealer?
I have never had a small bare spot that needed it so have never used it?

 

[harrisonm]

what don't you guys like about self etch primer? Isn't it for tiny exposed bare metal spots before basecoat or sealer?
I have never had a small bare spot that needed it so have never used it?

I don't dislike self-etching primer; I have just never used it. I have always had really good luck with using a DTM epoxy primer on the bare metal. Then, filler work can be done directly on the epoxy primer. I guess a guy gets used to what works for him.

 

[ir3333]

i agree. There are so many products now it's mind boggling and the quality is very high. Just learn how to use the product properly.
The only primer i use is CRE, from start to finish...from bare metal to final prime.

 

[Demonracer]

One of the reasons that the paint chips away is that the valve covers are used. Being that aluminum has porosity, They have absorbed the oil mist under the hood. Powder coaters bake aluminum pieces to burn off this residual oil. I blasted some valve covers, soaked them with acetone and let them air dry for 5 days. I then baked them in a toaster oven at 200 degrees before painting and sanding. They turned out very well and still look god 12 years later.

 

[barbee6043]

One of the reasons that the paint chips away is that the valve covers are used. Being that aluminum has porosity, They have absorbed the oil mist under the hood. Powder coaters bake aluminum pieces to burn off this residual oil. I blasted some valve covers, soaked them with acetone and let them air dry for 5 days. I then baked them in a toaster oven at 200 degrees before painting and sanding. They turned out very well and still look god 12 years later.

I agree. Demonracer has a valid point.
And I will add this comment. If you read the tech sheets of several or so auto paint co. they can comment on the use of self etching primers, that is the use of a certain primer (like epoxy) on that before any topcoat. The self etch has an acid and that enters into the equation. But I rather dislike Dipli Color for decades. You would be surprised to find some laquer derived spray bombs out there. Best bet is always a topcoat mixed at the auto paint store and a $30 HF gun. Costs more but fewer issues.

 

[harrisonm]

i agree. There are so many products now it's mind boggling and the quality is very high. Just learn how to use the product properly.
The only primer i use is CRE, from start to finish...from bare metal to final prime.

I looked up CRE primer, and all I found was CRE epoxy primer. Do they make more than epoxy primer? I was wondering if you used epoxy primer for everything.

 

[1WildRT]

Primer designed for aluminum....
https://www.amazon.com/So-Sure-TT-P-1757-Chromate-Primer-0084-348/dp/B0F7HQRL2N/?tag=fabo03-20

That said I agree sand in line with the fins... I also agree as much as I like my blast cabinet you gotta be damn careful blasting stuff that could potentially introduce blast media inside your engine...

And yes, cooking the covers to remove oil from the aluminum isn't a bad idea... Don't let Momma know you used her oven.... (She'll probably figure it out on her own)

Spray bomb etching primer that really works well..

https://www.amazon.com/U-POL-0741V-Acid-Primer-Aerosol/dp/B006HFM5YG/?tag=fabo03-20

 

[ir3333]

Yes CRE is Epoxy. It is also high build and sands easily. Unlike 2K urethane high build primer which can continue shrinking for months it is finished shrinking in 3 days. I like it because it dries reasonably glossy and you can see your bodywork! You will need a 1.7 tip. The high end shops use PPG VP2050. Word is it is nearly identical but more expensive. Many shops are using the high build polyesters instead of skim coating but i haven't tried any of them, you need a 2.5 tip.

 

[Amata Bene]

A lot of good advice and ideas, thanks. I'm going with a complete do-over. Like my ol' man said "The road to success is paved with failure". I do no not think there was an adhesion issue, as I'm having to be verry meticulous as I blast them to get complete removal.

I believe my downfall was using a DA to sand the tops. I am going with the wet hand sanding on this attempt. I'm pretty sure that will give me the results I'm looking for. I like the idea of from @harrisonm of sanding primer from the raised areas before moving on to the color.

Thank again for all the advice.

 

[70SwingerGuy]

Ill reiterate what @barbee6043 said, you need an intermediate primer between your self etch and your topcoat, self etch isnt made to be topcoated directly, its meant to adhere to metal and have a primer sprayed over top of it. I also agree with what @jos51700 said, sand it by hand, dont use a DA, its too aggressive for those small areas.

 

[Bodyperson]

I looked up CRE primer, and all I found was CRE epoxy primer. Do they make more than epoxy primer? I was wondering if you used epoxy primer for everything.

CRE is an implement primer. Not tested for highspeed auto use.

 

[MOPAROFFICIAL]

Hope everone had a good Thanksgiving.
Like the title says I know little to nothing about painting, most of my experience comes out of a rattle can. You can see in the pic what I'm going for. I just want a bright aluminum look not polished. I have decal the print shop made for the large flat area then a few coats of clear.

I painted painted the V-covers with a coat of self etching primer then 4 coats of Dupli-Color engine enamel with ceramic. This was a couple 3 weeks ago. Came to the shop today to get in some personal work while the sun was shinning and get home before 11++ pm. I thought all was going well till it wasn't. Started the sanding with 120 then 220 then final with 320. Notice on the first one the paint chipping/flaking off at the edges. Thought maybe the 320 was to aggressive to start so, I started the second one with 220 then the 320. Same thing.

What do I need to do to remedy this. Should I put them in the blast cabinet and start over with a different paint. Or, can I just use the same paint and do the sanding while it's a little soft not a 3-4 week cure time. Thanks for any advice.

Use a soft block sander and go the direction of the fins next time...