I just painted a bike frame (steel) with the steps outline below. However, every glancing contact with a rough surface immediately strips paint from the frame and I can see the metal shining through. This is the second time I've made this experience. I had expected that DIY paint may not look as great as a factory finish, but I had at least hoped to have it be durable enough that I don't need to worry about scratches every time I lean the bike against something.
- Removed one layer of old paint with paint stripper
- Removed second layer of paint (not affected by stripper) with sandpaper. Down to bare metal in many places, but not everywhere.
- Wet-sanding with 1000 grit for the entire frame to make it easier for the primer to hold firm
- Clean with water, dry with towel and air, then use brake cleaner (supposed to leave no residue) and alcohol (the kind you can use for cleaning or making fires or whatnot; 'Spiritus' in German). I was hoping this would remove all grease from fingers and such
- Apply 1-2 coats of primer
- Let it dry for 24h
- Wet-sand frame again with 1000 grit
- Wash, dry, clean again, same as above
- Apply base coat in 2-3 coats, letting it dry for at least 30 minutes between coats (paint is supposed to be non-sticky after 5-10 mins, dry after 20-30 mins, fully cured after 24h)
- Apply several clear coats (same intervals as 9.)
Now I realise this is about the cheapest spray paint you can get, but I had hoped that I did the procedure correctly. The frame has been resting for about 12 hours when I scratched it, but I don't think it'll get much harder, judging from my other frame I painted.
- The alcohol I used for cleaning wasn't good
- I should let each coat of paint dry 24h before painting over it (doubtful)
- Paint is shitty
Where else could I have gone wrong? Here are some pictures of the finish. There are some spots where I wasn't careful enough and it looks like some white powder stains the section, but over all I'm pretty satisfied.
Here is one of the two spots where I touched the frame against a stone wall. It's not well visible here, but it looks very silvery as opposed to gray (the primer color), so I think it's down to the metal.
One shot from the bottom. The gouges are an artifact of insufficient sanding, not of the paint job I think.