Howdy
I've got an old Cinelli stem I had to put back into use for the clamp diameter, so I could do a bar swap.
The stem has some nasty gouges and I'd like to glean some advice to remove / reduce them.

My thinking is to start with 120 grit emery clothe, and work my way to finer grit until it matches the rest of the finish.

Before I completely bugger the thing up, anyone ever do this right? If so, how?

nasty gouge picture
another nasty gouge picture

Thanks.

I remember these 1/A stems had a satin finish. Anodized? If you do anything with sand paper, you will have to do the whole stem to match the finish. Start with 400 grit minimum. Scotch bride green would be best to match the contours of the stem and then move up to 600,1200. This is tricky since you are moving toward a situation of repolishing the stem.

My retailer side says you need to replace the stem or sand/polish down those scratches to prevent stress risers. My rider side can show you a Cinelli stem with a far worse surface that I've used for over 10,000 miles. Andy.

Howdy, again.
I had an old, dingy SR stem in my parts bin, so I decided to go at it with 600-1000-1500 grit paper
SR_1 / SR2 / SR3

I thought it didn't come out horrible, so I took my CRS emery clothe to my Cinelli stem gouges (then MED, then FINE, 600, 1000, 1500).
CIN1 / CIN2 / CIN3 / CIN4

The gouges are pretty much gone. There's a faint one left on the front of the stem.
But as you can see, I took off some kind of coating. I don't know if I sanded off anodizing or just a normal patina from 20~30 years ago.
Anyone know for sure?

Regardless, closing the loop on this question, in case anyone was curious.

OP; Probably being overly sensitive. Those minor scratches are not bad enough to elevate to "regular gouges". However your approach to mitigating them is solid. Just don't remove too much material.

On the more serious side, I see a big spacer being used in the headset. A fat spacer in the stack on a threaded fork is somewhat unusual. Fork probably been replaced and not trimmed correctly to fit the head-tube length. Likewise, a Cinelli stem like this is basically a racer oriented stem for riders who like to have them bars down low for minimal wide resistance. Your configuration is way up high. Highly recommend a close check to make sure the minimum insertion warning line on the stem is not above the top of the stack...your concerns about the stem being weakened by the gouges adds to the potential concern. Just make sure you are riding safe. A stem breaking even at low speed is a nasty gouge guaranteed and on the other stem of importance...

/K

it's probably the anodizing layer. i've done the same thing a couple of times. they say the alloy will oxidize and it does. but in real life it's not a game changer, IMO. aluminum oxide isn't as durable as say titanium oxide, but it ain't like iron oxide.

[MENTION=320646]ksisler[/MENTION] - Thanks for the good warnings.
Yes - I was careful not to sand off the max-height line. I do have the stem maxed out.
The head set it some kind of generic thing I've never seen before, so I doubt is it's original. (I got the frame for free a bunch of years ago).
I'll talk to my LPB about the fork/head tube, see what he says.

Fwiw anodizing is not hard to strip off and replace. A battery charger and diluted sulfuric acid are all you need to anodize. You could easily experiment with
some scrap aluminum that you anodized then sanded in the same way as you have already done to see how a repeat anodize on the scrap looked to see
whether you would want to remove the rest of the anodizing before reanodizing. A google on anodizing should point the way and sulfuric acid is used in some
drain cleaners. Oddly the lye variety drain cleaners will strip off the anodizing but unless used carefully will etch
the aluminum, not cosmetically good, necessitating a buff and polish to recover the nice Cinelli look.