Bicycle Mechanics - Sanding down old paint

Hi All,

I'm in the process of bringing new life to an old frame/fork. I'd like to strip it down to the bare metal and repaint it. Does anyone have any experience in that area?

I've got a power drill and a dremmel tool, but that's as advanced as I get. Would a paint removing chemical be better than a mechanical removal?

Thanks!

If you are preparing an aluminum frame the rules are very different from a steel one.
For steel:
A wire wheel in a drill, (or a 4.5 inch wire wheel in a grinder) is very fast and effective. Sanding will be good for open areas. Dremel bits can be handy for braze-ons and joints.

For aluminum alloys:
Do not use the wire wheels. They will marr the surface dramatically and the metal will contaminate the aluminum. Only use wet/dry(black) sandpaper when you sand, as the others can contaminate the aluminum pores. Scotchbrite plastic abrasive wheels in a drill work decently. Chemical strippers are preferred for the larger portions, due to the lack of abrasion.
Even with the chemical stripping you will need to clean the edges and details with some sanding or scotchbrite.
To prep either clean it very thoroughly with acetone after the process, to degrease it.
Aluminum will have to be primed with a special primer called Zinc-Chromate. NAPA has it usually. Coat it just enough to be opaque, then paint normally.

If you're thinking of throwing paint on it yourself, I wouldn't bother stripping them down to the bare metal. Partial sanding, even down to the original primer should suffice.

I have had more problems from old paint lifting under new paint than hassles in stripping all the way. I go all the way fresh, saves the worry later.

I used good ol' elbow grease and sandpaper on my dragster frame, but that took fuggen ages. On a different frame i used a combo of electric sander (for the larger parts of the frame), a heat gun and scraper (it quite literally peels away :) ) and sandpaper for the fiddley joins. You could try paint thinners but I found it did bugger all when I tried it.
If you're not up for some hard work, a quick and easy method is to find a place that can sandbalast it for you. Try your LBS, some places offer sandblasting and/or frame painting.
Good luck.

Sandblasting on steel is the fastest way to go, if you can find a place with a cabinet large enough.
On aluminum, do not use sand. They would use either plastic pelets or glass grit. True sand will cause silica contamination in the surface and the paint will not adhere propperly.

Hi All,

I'm in the process of bringing new life to an old frame/fork. I'd like to strip it down to the bare metal and repaint it. Does anyone have any experience in that area?

I've got a power drill and a dremmel tool, but that's as advanced as I get. Would a paint removing chemical be better than a mechanical removal?

Thanks!Use a chemical stripper.

I agree with sydney, unless scratched\ rusted. Why damage a perfectly smooth surfaced tube?
Once you've made scratches..you have to sand them out with finer and finer papers -they show under new paint.

Oh, if you get all the paint off, clean the metal of hand oils, etc before painting primer.
Only thing I've used, (worked o.k) Lepage Poly-Superstrippa.
3 coats 1/2 hour between.