Sanding and polishing de-anodized threadless stem
 

While I've been able to find plenty on stripping the anodizing off black threadless stems (oven cleaner worked fine), it's been more difficult to find good advice on giving the stripped part an attractive polished aluminum finish.

I've come across several people who have simply buffed the part with polishing compound...
(see:http://www.fixedgeargallery.com/arti...less4x1000.jpg)

...but I'm looking for a smoother, more mirror-like finish.
(see:http://www.interlocracing.com/stem_irdtange.jpg)

A bit of Googling brought up a site on polishing aluminum spinners for model airplanes (http://www.rccaraction.com/MA/how_to...Spinners_1.asp) that would seem to be relevant to polishing aluminum bike components. It begins with sanding, working from 240 grit up to 1000 grit, then buffing with a Dremel and polish to achieve a mirror finish.

I'm curious to hear if anyone has tried this method, has concerns about applying it to a stem, or has other suggestions for achieving the finish I'm looking for (other than simply buying that IRD stem).

Thanks in advance.

Use whatever lowest sandpaper grit is needed and proceed right on up to atleast 1000 grit wet/dry paper. More grits the better finish. Then get a buffing wheel made of cotton and use tripoli compound and then another wheel using white compound and finally a felt wheel using jewelers rouge. You can omit tripoli but I wouldn't omit the white as some "cutting" is still needed. Jewelers rouge only polishes and does not diminish scratches that other grits leave behind. As for tools
all you need is a variable speed dremel, electric drill, grinder etc.
Easy process. For that I'd estimate no more than 1 hour work and likely much less. You're removing very, very little metal.

Why bother. Won't it just end up oxidized anyway?

Yes and no. If you regularly use an aluminum polish on the part it will stay very shiny. I always use Mothers Mag Wheel polish and it works very well. It is still more work keeping it polished than having it anodized. Good luck.

Tim

I have had great success with working with progressively finer sandpaper all the way to 2000 grit. Your goal in sanding is to remove the previous sanding marks from the coarser sandpaper. They must be completely removed or the scratches will show in the end. It's a lot of work but looks great at the end. Use plenty of water and dishwashing soap. I don't use machine polishing, however, always hand polishing with a fine metal polish, (not rubbing compound or car polish) also a lot of work but if you've done your sanding correctly will turn out to a mirror like finish Usually the polish will leave a protective coating that will protect the alloy for a period of time. Just clean your alloy with the polish when you clean your bike and the mirror like finish will always be there. My Campy Super Record seatpost and the downtube shift levers came without anodizing from the factory in the 80s and still look brand new. They look better than the anodized parts. They are not a big deal to maintain at all. Unlike filtersweep's comment, "Why Bother?" Why bother to wipe after using the bathroom. It will still stink and get dirty again! Bad attitudes like that are annoying on this forum and totally unneeded. I think polished out parts look better than anodized parts although a little more work, but you got to clean your bike anyway. Besides anyone who doesn't care about their bikes isn't going to be polishing out their parts. They probably leave their bikes outside open to the elements anyway, you however probably care about your bike and keep it safely stored out of the elements so it wont easily get oxidized.

Just to add one side note... There are many of us people in between those that require their bikes to be museum pieces and those that store their bikes outside... And we do are about our bikes. I suspect that some people that store their bikes outside are about their bikes as well. :D

But, back on topic. There is some interesting information in this thread, and when I thought about polishing my aluminum, I would have gone directly to the Dremel...

If there are no scratches big enough to see after cleaning the part, is there really a need to use any sand paper? Or is 1000/2000 grit sandpaper so fine that it removes scratches smaller than are visible, but large enough to impact the quality of the finish but still too large to polish out?

I personally don't need a mirror finish, but do like polished metals... Is there a difference in approach between polished and highly polished at the sanding stage? I would think that the effort of final polishing will make an obvious diffrence...

A coat of clear lacquer or polyurethane will help protect the finish from oxidation.

The better the final finish, the stronger the part; small gouges and sanding marks can become stress risers (where cracks begin).

I've used SemiChrome polish for final finishing with good success but any mildly abrasive metal polish will do the job.

I stripped and polished the seatpost and crank on my single speed:

http://community.webshots.com/photo/...68014369jHohCP

I've since done the stem.

Bare aluminum will stay shiney with only occasional application of metal polish if you keep water off of it and never touch it with your bare hands.

I used a pad sander and then fine steel wool and then polishing rouge on a cotton wheel mounted in a drill press. I masked off the part of the seat post that is inserted into the seat tube so it would not be a loose fit.

Thanks for the information so far... it seems like a relatively straightforward (though potentially time consuming) process.


Yep. The stripped part doesn't have a smooth finish... it's very dull and somewhat grainy. My hope is that sanding will improve the surface of the stem, which looks something like this:http://www.fixedgeargallery.com/arti...eniumx1000.jpg


I'm also very interested in this. A mirror finish seems to be achieved through obsessive sanding and a lot of polishing, but how do companies like Nitto achieve that beautiful 'dull-bright', satiny finish?

Satiny is the look of the sanded piece before you go into the polish/buff stage. You can also simply buff the metal with compounds without prior sanding in order to get a nice bright but not quite mirror-like look. It's the removal of all the tiny little scratches/bumps that make the surface flat enough to reflect like a mirror.