I've noticed today that a bit of the paint on my passenger door has flaked/chipped off approximately 1mm wide (possibly from a clumsy passenger or spiteful pebble) and it looks like a bit of rust is starting form.

Also, while inspecting this small ship, I found on the inside door sill a half-inch rust spot forming under the paint.

My question is are there any quick solutions to keep the rust from getting worse or should I take the car to a body shop this weekend for some spot treatment? After reading through "Black_SC's" thread about his recent rust problem I'm not taking this lightly.

 

well if you want to do it good then, you'll need sand paper maybe like 800 grit, 1000 grit and 1200 grit, primer, paint (same colour as your car, you can get it matched) lacka(donno how 2 spell it the stuff that makes your car shine) , sand down the rust so its bear metal, then use higher grit each time and with 1200 grit use with water, once dry spray a coat of primer, then sand it with 1200 grit with water, wait till dry, then primer it again, then sand it again, then spray paint it (same colour as your car), sand it(with 1200 grit and water), then spray it, then sand it then spray lacka and sand if need then buff(with a buffer) or just wax your car or something should look like new

thats what I did, I'm not a professional .. but my car looks like new and you can't even tell i did it but i did, moral of the story rust isn't there and it looks great.

 

While the other reply is good for a do it yourselfer I think this entirely depends on the color paint you have. Some are harder to "touchup" than others. I know Pearl specifically is difficult but the other metallics are also a challenge. I would assume some of the non metallic colors are a bit easier to match. This is not an easy job if you are a perfectionist alot of prep work etc

I am not sure what OEM paints were made from in the 90's but I believe none are lacquer based. I think most are water based with clearcoat as finish.