by Ride_on » 31 Jul 2010 07:33 pm
You are not going to fix that with a touch up brush, although it might look slightly better. The small rust spots you might get away with a limited repair, but it going to end up spotty + lumpy. It might even be rusted through from the inside, which will be more complicated.
Haynes manuals have a basic paint repair instruction usually, but don't explain much about rust prevention. If you leave any rust or pinholes in the metal it will rust through again.
Basically remove all the rust (mechanically+chemically), prime with zinc primer and flat down with 400 wet+dry (wet) until perfect and you can see all the paint layers fading out around the repair spot, more primer and flat down as required. The original paint work has several layers (6 coats?), so you need to get back up to that level of thickness.
Once its nice and flat then mask up and over spray the repair by 50%, in your case it looks like the whole door should be done. Flat down with 1000 wet+dry (wet) and/or rub down with T-cut.
To be honest these days I leave the the main painting to professionals, home safe paint is just not that good. You might get the job done for £100-200.
1980 345 DL_______1987 360 GLE (project car)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7