Painting steel garage entry door...

[JeffKeryk]

32" garage steel back door. Primered, but was installed maybe 15 years ago. Has some surface rust at the bottom.
I will sand off the rust and lightly sand and clean the rest.
I was thinking of using my clay mitt to maybe get out years of impurities?

I ain't no painter... Should I use a Rustoleum door paint or just a basic satin paint?
Should I prime it 1st or use a paint with primer?

I appreciate your guidance.

 

[PimTac]

If you use the clay mitt then don’t use it on automobiles in the future. I would skip that part.

Ideally the door should come off. That way you can sand and prime/paint the bottom. Bottoms tend to be forgotten. Do you have any way of securing that entrance while the door paint dries?

 

[JeffKeryk]

If you use the clay mitt then don’t use it on automobiles in the future. I would skip that part.

Ideally the door should come off. That way you can sand and prime/paint the bottom. Bottoms tend to be forgotten. Do you have any way of securing that entrance while the door paint dries?

I will skip the clay mitt, thanks. I will remove the door.
I will finish the job early enough, but there is no problem leaving the door off. Maybe a possom or raccoon will steal my prized Snap On 3/8 torque wrench?
I live in a very safe place.

 

[Kira]

Derust, sand evenly and apply Rustoleum Grey Metal Primer. Many call it "clean metal primer".
Then use the color Rustoleum oil base you like. Remember, don't go too far afield with a wacky color.
I'd think a brush (natural bristle) would do for a single "man door" sized door.
Dry day....light sand between coats...get all the powder off with a tack rag or even a light wash with ever so mild soap and water.
Second coat.
The red Rustoleum primer is good stuff for more rusted / less cleaned metal.

 

[KJSmith]

Natural bristle is for latex paint.
China Bristle for Oil base.

Sand it, use a rust reformer, prime it, and paint it.
You can use oil, if you want.
Or, Sherwin Williams has a paint called DTM (direct to metal).
It's a latex made for metal.
I'm sure other brands make a similar product.

Latex is easier clean up. (water)
If the texture of the door doesn't bother you, you can use a roller.
A Pro would spray or brush it.

 

[JeffKeryk]

What size grit paper should I use for surface rust?
What size to lightly scuff for paint? 400?

Thx; I ain't no painter.

 

[KJSmith]

I use an orbital sander and 120.
Unless it's really bad.
If you try to use lower grits, you can see swirls in the metal.
It all depends on how picky you are.