I'm pretty sure you can't paint over egg stain without prep and primer. If you are a novice at touch up work I would suggest leaving it to the pros.

4 oz won't cover much of the roof panel either.

 

One of those "if you have to ask..." moments.

 

Woody, let’s see a picture of the egg spot, please .
do you mean egg sized or egg yoke and white , burned into the paint!

 

You're making me hungry now talking about eggs...

 

It's not buffing out.
I know better than to try first that's why I'm asking. There are many spots on the paint elsewhere that need attention and hard water spots that will kind of come out with a clay bar. Paint overall needs a detailed buffing by a professional. The egg spot well there it is. At the passenger front door area of roof.

 

I'm not sure why you would call it an egg spot, but I'd say that trying to figure out the issue via a photo is pretty much nigh on to impossible in this situation.
It could be a stain of some sort, or IMO thin paint wearing through. Regardless, take it to a profession and ask what they would suggest to remedy it.

Under no circumstance consider repainting it yourself. It will be way too easy to make a bad situation worse.

It's one thing to trying to fix a few rock chips etc., but totally something else to address an area repair like that.

 

It's an egg spot because when I picked it up from buying from on-line auction pieces of the white egg shell stuck by the white to the roof.

Agree with your opinion whopper, let the pros handle it. Or leave it be.

 

Are you sure the spot was NOT there prior to finding the eggshell pieces ?

Cause it kinda looks like thinning paint, but the pic rez makes it hard to give a better opinion.

 

Egg stain will actually etch into the paint, I've dealt with it before. It can change the color of the paint in odd ways.

Prep is usually take it down to bare metal and start over again, or it will effect the new paint. At least that's what we did back in the day... (egging cars was a halloween thing in the stone age)

 

This is due to dust.
The previous owner did not clean the dust after preparing the surface for painting. At first, the paint looked decent and the new buyer did not notice any flaws. Over time, the paint began to swell and crack. Judging by the risks under the window, someone tested the detected damage and fell into despair.
Well. nothing new...
... and nothing critical.
you (Americans) love to do it yourself, and that's good,
but sometimes the consequences of unprofessional painting are depressing. So I see one of these sad results.
But again, there is no big problem.
How would I act in such a situation - I would just take the gate off the hinges and take it to a professional. If, after a thorough inspection, something like this is found on other parts of the body, the whole car should be repainted by a professional.
But, as I understand it, you plan on repainting yourself.
Then like this:
1. Let the color be picked up by a professional in a specialized store, they have computers and mixers. You will need a body part for the sample, usually a gas tank flap. By the way, it is very difficult to remove it, strong rivets for working with a drill machine and a drill with a tip for metal;
2. treatment of the entire front surface of the gate in order to tear off the old paint. Use a grinder. In places of bends sandpaper and fingers. Try to keep the residual layer across the entire surface. It should not be that somewhere you see a thick layer of old paint, and bare metal on the ribs.
3. Primer / waiting for the primer to dry / painting with the first coat / again drying / second coat of paint + drying / if a third and fourth coat is needed (but this is unlikely) / final drying of the paint / varnishing / inspection and longing that again nothing happened / acceptance decisions to go to a professional to redo everything.
But seriously, the work is difficult, it requires special skills and a special tool. There are requirements for a painting room. It will take a bunch of additional materials and chemistry.
Judging by the picture, the previous owner has already tried his skills, The result is before your eyes.
If you still decide to fix the paintwork yourself, you are a real fighter and I sincerely wish you success. Preview numerous videos on the Internet, purchase and prepare everything you need. The most important thing is to find a couple of old hoods in the trash and practice this.
To paint the gate you will need: 250 grams of enamel complete with varnish, a tank of primer, 3 types of sandpaper, covering material and masking tape, solvent and degreasing liquid, dry cleaning wipes, hand grinder, airbrush with compressor, various others little things. It sminimal set. I recommend to remove the gate before painting - for the convenience of work. Before painting, lay the gate at an angle or horizontally on a workbench or table - this way you will avoid unnecessary streams of paint. Do not be lazy to remove the door trim, this will save you money.