[hyankov]

I am restoring/converting my wife's bicycle. It's a white aluminum frame. There are multiple scratches and scuff marks. What is the most effective, fool-proof way of fixing that? It doesn't need to be perfect, just better.

I'm leaning towards white nail polish.

Here's an example:

 

[Loll]

Yes, or model shop paint. You will likely have to buy a few before you find the perfect match. On the way home pick up a small and a fine brush from the art store.

 

[jannmayer]

White nail polish is your best bet. White paints generally don't cover dark markings very well, but nail polish is thicker and should work fairly well.

 

[hyankov]

Am I supposed to sand it, before or afterwards?

 

[Steel-Onions]

White Enamel radiator/bath tub paint, cheap and tough

 

[jannmayer]

Am I supposed to sand it, before or afterwards?

If the scuffs are rough, I would sand it enough to smooth it out. I'd also consider sanding lightly to clean the surface, but I don't think that's critical.

I don't recommend sanding after touching up the paint. The nail polish will be thicker than the surrounding paint, so you're likely to take paint off around the touchup before it gets much smoother.

With a nail polish touchup, I'm happy if the spot no longer jumps out at me. It will always look like a touch-up when you look right at it.

 

[hyankov]

Could I use a 2X paint+primer spray directly on it? With minimum prep beforehand? Anyone done this?

 

[jannmayer]

Could I use a 2X paint+primer spray directly on it? With minimum prep beforehand? Anyone done this?

You can do this. You'll need to mask around the areas you are touching up. Since spray paints are rather thin, you will want to sand it down a bit beforehand. With any kind of painting, your results depend on how well prepared the surface is.

 

[Loll]

Could I use a 2X paint+primer spray directly on it? With minimum prep beforehand? Anyone done this?

That, in my bias opinion, is trying a bit too hard on something that is not worth much. Even on a so call dentist salary bike, model paint or nail polish is about the furthest to logically take it, unless there is an unsightly scratch that bugs the heck out of me, then I would consider taking the repair further.

But if that is your hobby and you already have all the available parts and tools in the garage, go for it.

 

[JKA]

Just put a Band-Aid on it. It will heal if you leave it on long enough.

 

[Cleared2land]

Consider them scratches more like 'Badges of Honor' and go ride.

 

[006_007]

White electrical tape.

 

[Travolta]

white nail polish

Yes. Or if you got some spare white acrylic paint, use that.
Buy several shades and try it out first. Otherwise, thats your best and cheapest option.

Nail polish has a wild variety of colors and effects so even metallic or matte paint touch up jobs are possible.