I have a older bike that the stem has worn paint. The paint LOOKS good but does not protect fromt rust which I found out after cleaning it up a little and having some surface rust come up on the thin parts.

Can someone tell me what kind of flat clear coat I can use on it to protect from rust but keep the original look? Link to specific brands and type would be majorly helpful.

The original paint is flat black with decals in good shape. So the clear needs to be flat for sure.

Can I just use a scotch brite to prep it before spraying?

Scothbite is a very irregular grit - bad juju!. 600 grit wet/dry sand paper is the way to go.

Why does your cleear coat have to be matte, aesthetics?

The thing is, if you have rust in the pitted paint, just painting over it will not stop the rust growth.

Watch out that the solvents in the clear coat (paint) do not soften the decals and cause them to lift.

Yeah the original part is a matte look. It flat black paint on it originally which I am looking to maintain.

The paint is not bubbled or anything. It is not pitted either. It is just thin in some parts.

I'll just reiterate, all it takes is one single piece of large grit in a Scotchbrite and you can ruin your entire paint job.

Flatting agents can be added to any paint to give a matte finish.

For the types of finishes I am most familiar with, you are usually better off using gloss clear coat and treating the finished surface to suit your needs. Gloss usually has a highest concentration of resin.

Another way to get a matte finish is to paint with clear and then sand using that same 600 grit wet/dry sandpaper after painting. You will be able to achieve a uniform luster to the surface.

Another way to get it is to use ground punice and mineral oil as a slurry to break the sheen on the surface.

What material do you plan to use as your clear coat?