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.

 

[Bighouse]

Hand sand gently.

 

[dadsbee]

Get them shined up... paint again and then take a towel wrapped around a dowel and wipe the tops with lacquer thinner.

 

[Sam69sat]

Maybe incompatibilty between the etching primer and enamel? Is the self etching primer still adhering to the aluminum on the edges that chipped? The duplicolor engine enamel page shows Gray Engine Primer on the primer tab.

Engine Paint| Duplicolor

Complete your next automotive paint project using Duplicolor Engine Paint

www.duplicolor.com

 

[Amata Bene]

Hand sand gently.

That was my first thought. I may go that route.

 

[Amata Bene]

Maybe incompatibilty between the etching primer and enamel? Is the self etching primer still adhering to the aluminum on the edges that chipped? The duplicolor engine enamel page shows Gray Engine Primer on the primer tab.

Engine Paint| Duplicolor

Complete your next automotive paint project using Duplicolor Engine Paint

www.duplicolor.com

That is how I did the block. Talked to a fella at the parts store who "claimed" to be a painter and said I should use the etching primer because it's aluminum. Again that's why I love my dogs, they don't claim to know nuttin but when it's time to eat, sleep, or s##t and if somebody's at the door.

 

[fesser]

The problem could be the etching primer, regardless of what the store employee said. I have used various etching primers over aluminum (boat stuff) and most, if not all, of the etching primers say that they are not to be top coated with paint. They need a primer, over the etching primer.

 

[Bird 426]

Looks like it pulled the primer, adhesion issue. Blast with glass bead. Acid etch would be best. Not sure if I would primer it, would need to scuff it before paint. I would tape it, cut excess off with an exacto or razor blade, you may have to do the paint in more than one step. That paint probably isn't the best for the job. You may get to do this more than one time, it takes mistakes and trying something different to get the results that you are happy with. You can polish or scotchbrite it after it's painted. POR 15 would be a good choice for paint.

 

[Coelacanth]

If the orange paint is flaking off while sanding it, it looks like it didn't bond properly to the valve covers. As Bird 426 said, it's an adhesion issue, you need good surface prep before painting. When you re-do it, use a sanding block instead of hand sanding so you know you'll be sanding the raised areas flat, and not have your hands/fingers dipping below into the valleys.

 

[dadsbee]

Get them shined up... paint again and then take a towel wrapped around a dowel and wipe the tops with lacquer thinner.

Like so...

 

[Bird 426]

Both #9 and #10 work. It just takes practice, trial and error. Block sanding is good, go fine, and with water for lubricant.

 

[Amata Bene]

Prep work - Blasted with aluminum oxide then blown off and wiped down with acetone. Painting - Etching primer applied, 1 coat. Allowed to dry then the color was sprayed in lite coats, maybe 30 min between coats. Last coat was wet to the (my) eye. Sanding was done with 6" IR orbital sander roughly 3 - 4 weeks later AKA today.

 

[dadsbee]

The orbital was your pitfall. As I noted earlier I would have done the sanding FIRST and wiped the top clean with lacquer thinner... but in this order the sanding should have been done with the paper wrapped around a piece of 2 x 2 wood and straight back and forth the length of the cover.

 

[MarPar]

I've used this little guy with much success

Micro Hand Sanding Block Kit, 3.5” x 1” Pad, Hook & Loop Backing, 40 Sandpaper Sheets, 5 Each 60 80 120 180 220 320 400 600 Grit - Woodworking Sander

Micro Hand Sanding Block Kit, 3.5” x 1” Pad, Hook & Loop Backing, 40 Sandpaper Sheets, 5 Each 60 80 120 180 220 320 400 600 Grit - Woodworking Sander

tcpglobal.com

 

[kiwigtx]

Like so...
View attachment 1955068View attachment 1955069View attachment 1955070View attachment 1955077

You read my mind and posted first ....that is the easiest way to do the job ^^^^

 

[rickseeman]

On the engine in my avatar I sanded the flat spots first so it would be easier to shave them with a razor blade after I painted them. I started shaving after an hour of drying. (Not fully dry.) All I can think of for you to do is reblast and start over. It took all day but I'm happy with the results.

 

[Bird 426]

There's another way, I like the razor blade idea too. All suggested here will work.