Metal door has chipped paint. Can't sand it smooth

Have you tried stripping paint with a gel stripper. If that doesn't work perhaps using Hammerite rust priming paint. Gives it a hammered finish which might camoflage the uneven surface due to rust,

itHI Wanda, Do you know what kind of paint the door has been painted with previously that has chipped? You could use a brush-on paint stripper gel or liquid. It would be easier to do if you take the door off to work on it. AND be sure to work in well-ventilated area or outside is preferable as the paint stripper (depending on the brand) can be really strong smelling and toxic.

If you don't want to use a stripper you could try a heat gun. It gets really hot and you can move the gun along with a metal paint scraper and gradually remove the paint that way.

I think either way it might be a messy job. And to possibly prevent chipping from happening again, be sure that the door is totally clean after you remove the old paint - use TSP to get rid of any residue on the door. You could lightly sand also then prime and paint. Depending on which way the door faces (does the sun hit it), ask the paint store what they suggest. I favor latex primers and paint so that it is low VOCs and easy clean up compared to oil based paints.

Good luck. Just take your time to get the best finish.

If it is big use car bondo.

Actually any size chip for a bondo - just read the labels to find the right product. Bonds is great because you can sand it smooth before painting.