I have now laid bare a metal frame by following advise in a previous answer. Now I want to remove its white paint coating. I've briefly tried manual sanding (with P180 sandpaper), but this promises only little progress. The sanding is in preparation for painting the frame with a new color. The frame is approx. 60 x 60 cm with its bars' diameters at approx. 3 cm.
What type of grinding machine (for home use) and what type of sandpaper would be best for this task? And how will I know when I'm done before the new painting?
Best Answer
You do not need to strip all the existing paint off, though you can fairly easily with a chemical paint stripper if you want to.
You need only to remove the shine from the existing paint; what I call de-glossing, to prepare it for a new paint coat. You should be able to use the 180 paper to accomplish this, but utilizing successively finer grit paper will incrementally improve the look (smoothness, shine) of the new paint.