Keeping the frame bare metal
so i recently stripped the paint off of my old KHS Gran Sport road bike. i was originally going to rattle can paint it but my first attempt at painting it failed. i re-stripped the paint but i am realizing i really like the bare metal look and want to keep it. anyone know of any good techniques for keeping the bare metal but without it rusting up? i heard that clear coating it doesn't work because the clearcoat chips off in about a week. i heard one technique works is using a metal polish like Mother's Mag and Aluminum Polish and just apply it monthly. i also heard from a guy in a bike shop that heating up the frame with a torch and then rubbing peanut oil on it also works. has anyone used either of these methods with any long term success?
Rivendell uses clear powder coat on some of their frames.....my guess is they wouldn't if the powder coat chipped off in a week.
Brompton has been clear powder coating some of their frames for several years. Your information regarding clear powder coat durability is out of date.
I was actually hoping to avoid powdercoating: I'm really broke right now and was hoping to spend under $40. But if powdercoating is pretty much the only viable solution then I'll look into it.
You could try using clear coat, with your current budget in mind, and then bite the bullet later if you really like the look and powder coat....I reread your post and you were referring to clear coat chipping..not powder coat..sorry for misread.
If you go this route, I would do lots of coats, follow the instructions on recoat to the letter and then let the whole thing sit for as long as you can stand it before doing the build.
I do know that when I did a full rattle can on my bike (stripper, primer, paint, clear) it ended up costing almost as much as a powder coating would..... check arround and see what the local prices are....I would hope the prices are less in SLO than in the bay area
Last edited by squirtdad; 03-24-09 at 09:37 AM.
Reason: spelling and readability
yeah, that makes good sense. cycling is pretty big in SLO and i would imagine there has to be a powder coat place near by. thanks for the advice.
Dinosaur on wheels
I would think that even if you have a tight budget, that realistically in the long run painting the frame/powdercoating will save time and money in inself... not to mension look better for a longer period of time.. just my two cents
Originally Posted by DISPENCER
Make sure that your surface prep is not cause for a bond failure. Then try using a clear polyurethane vs. a clear acrylic. I don't know of a clear powder that is not polyurethane. You can obtain the clear coat in a can from McMaster Carr. It is their part number 7961T5. An 11 oz. can will cost $4.95 if you purchase less than 6 or $4.45 for a full package of 6.
If your bond is good you should have good success with your application. The polyurethane is more flexible than the acrylic finish.
I used the duplicolor clear coat rattle can from the local kragen on my frame a few months ago and it's holding up fine. I used the polyurethane version, not the acrylic version. I don't know if it's going to last in the long term, but so far so good. No chipping or anything like that.
Do you have some photos? I would like to see how they look.
Originally Posted by lemondzurich
This was the original use of WD40, as a way to prevent corrosion.
I had mine clear powder coated for $AUD40 (about $US25), but I had to do all the prep and masking of threads. I'm pleased with the quality of the job so far.
I sanded mine by hand to 800 grit. If I were to do it again I would go further, maybe 1200 grit,and I would pay more attention to the areas around the lugs. Once the powder coat goes on, scratches tend to show up a bit more than before, so careful sanding and polishing are crucial. I would also pay more attention to the brazing, sanding it more to neaten it up a bit more and polish it to a high sheen. Polished brazing looks like a neat lug lining job, and the extra effort will be repaid.
I can't stress enough how important cleanliness is for a good job. The more the frame gets polished, the higher the likelihood that fingerprints will show, and finger prints will etch into the steel very quickly. I have however considered leaving a single thumbprint as a feature and for identification purposes.
It's worth shopping around for a powder coater who understands your requirements. It shouldn't be an expensive process..powder coaters use clear coat frequently and they should be able to include your frame with other jobs, without extra set up costs.
Also, if I do this again, I would have the frame abrasive blasted first. Mine was chemically stripped, and then they used some sort of powered wire brush which left fine scratches. Most of the polishing was necessary to get rid of those scratches.
IMO, clear powder coat will be the toughest and most durable finish available and give the most bang for the buck. A 2 pack finish is also likely to be pretty durable, but I have no info on its use on bikes. I do know it's used a lot in marine applications and is well regarded in that area. I'd stay away from a polyurethane finish. I tried using it as a rust preventative measure. Polyurethane doesn't stick well to a polished surface, it will peel, and when it does, the whole finish has to be stripped and redone. Spray lacquer can bo touched up, but will probably require dismantling the bike to do so.
Lastly, if I do this again, I may just sand the frame to 800 grit or so, and put some extra effort into sanding the lugs to 2000 grit then using a powered buff to bring up a mirror finish.
I'll be watching this thread to follow progress. I'm currently at the stage of assembly where only the cables and chain have to go on.
Pics WILL follow! Patience,patience...
Edited to add...Squirtdad's idea is a good one i.e. do a clear rattle can job to see how it looks (and to show up any scratches you may have missed) A rattlecan job will be reversible if you decide to powder coat later, but I wouldn't expect the same durability as powder coat.
Last edited by Fidelista; 04-02-09 at 04:20 PM.
I don't have any pictures of the painted frame. Here's one pre-painting:
It looks pretty much just like it though. The clear coat doesn't really do too much to it. Maybe adds a tiny bit of gloss. I can take some closeups if there are specific things you want to see.