Why is painting so hard? Even a simple metal bracket.

[Kurtatron]

I’ve swapped an engine, done multiple timing belts, and even learned to weld, but I have never figured out how to paint.

Oh, I’ve tried, but every result has been a miserable failure. Everything I’ve painted, the coat comes off cleanly with a drag of the fingernail. I’ve used different paints, and primers.

My latest humiliation was a simple piece of scrap metal. It’s meant to hold a brake cylinder to my minibike.

I did not sand the piece because the metal is not smooth to the touch. It’s scrap that was weathered to a rough surface. All mill scale was removed using vinegar. Acetone used afterwards. You can see what the scrap looked like before I cleaned it.

I sprayed rustoleum professional primer. One coat, then waited a few minutes, then a second coat. Precisely as the instructions stated.

I waited five days later. The rustoleum sheds paint so easily with my fingernail. . Why is painting so hard? The paint gods would tell me that I need to sand the surface, but how, oh how, oh unknowable ones are you supposed to know when you’ve sanded enough?

I don’t understand why painting has to be so hard. Is there something that can be done to foolproof painting? Some kind of device that reads the surface texture and states your surface is prepped for paint?

GAAAAAAAAAAH.

 

[slacktide_bitog]

Perhaps the vinegar and acetone prevented the paint from sticking. Is it too humid out there?

Do you have any pictures of your painted piece?

Brush loose rust off with a metal toothbrush, and if the rust is still bad, use POR-15 first, before any other primer or paint. Then, use primer, then paint, then a clear coat.

 

[CDX825]

Spray paint seems to be lacking in quality in recent years. I have been painting stuff for years now and never had as much trouble with spray paint as I have in the last few years.

 

[Lubener]

Doesn't look difficult to me. It's as hard as you make it to be.

 

[97prizm]

I’ve swapped an engine, done multiple timing belts, and even learned to weld, but I have never figured out how to paint.

Oh, I’ve tried, but every result has been a miserable failure. Everything I’ve painted, the coat comes off cleanly with a drag of the fingernail. I’ve used different paints, and primers.

My latest humiliation was a simple piece of scrap metal. It’s meant to hold a brake cylinder to my minibike.

I did not sand the piece because the metal is not smooth to the touch. It’s scrap that was weathered to a rough surface. All mill scale was removed using vinegar. Acetone used afterwards. You can see what the scrap looked like before I cleaned it.
View attachment 345000

I sprayed rustoleum professional primer. One coat, then waited a few minutes, then a second coat. Precisely as the instructions stated.

I waited five days later. The rustoleum sheds paint so easily with my fingernail. . Why is painting so hard? The paint gods would tell me that I need to sand the surface, but how, oh how, oh unknowable ones are you supposed to know when you’ve sanded enough?

I don’t understand why painting has to be so hard. Is there something that can be done to foolproof painting? Some kind of device that reads the surface texture and states your surface is prepped for paint?

GAAAAAAAAAAH.

Try zinc chromate. It's a yellowish coating that aircraft manufacturers use.

 

[Snagglefoot]

Etching primer would be my recommendation.

 

[#18FAN]

Sandblast
2k primer followed by a 2k urethane I’d have it looking like a piece of glass in about a hour.