Hi,
I have a Sugino crank w chainring that I would like to have electroplated black.
I'm reasonably sure the crank is a steel alloy - correct me if I'm wrong.
I'm looking for a reputable plating/polishing firm to do this. Any ideas?
Image attached & thanks for you kind assistance, Jim near Baltimore

Your best bet is to contact a local motorcycle custom shop. Be warned:quality plating is not cheap.

I'm guessing you want this for a fixed gear or single speed right? I believe there is an SR custom crank that looks similar and it black. Also I have seen annodised black campy cranks on ebay. You might get something much nicer in black and in the end payed about the same as you would have to have that one electroplated. That being said you can probably get it plated black. I had a fork plated for $70 CND so a motorcycle parts plater should be able to do it for 50-100 bucks. Oh and they are alluminum not a steel alloy and a many platers will do alluminum. I'm not sure about annodising though. I believe that is something different.

That looks like an inexpensive swaged crank. Don't know if a plater would want to do it because the cleaning and plating solutions would penetrate the interface, causing problems. Also, parts that get plated have to be buffed and polished first and it would not be possible to get into the sharp corners, nooks and crannies, so those areas would look "dirty" and I suspect the swaged joint would "bleed" plating chemicals. If your heart is set on making the crank black, powder coating may be a better idea.

I am a roadie and have no use for a front derailleur - good guess.
I need the outside ring to prevent derailling when upshifting.
You and the other guys have given me some very good advise - thanks.

One thing about that particular Sugino crankset - the 52t outer ring is steel, and is riveted to the integrated pantleg protecter/spider. Keep this in mind when inquiring about anodizing or electroplating.

-Kurt

Follow-up . . .
I contacted my local motorcycle shop and he said he doesn't send stuff out to get plated anymore. The EPA has driven many out of the business, and the rest may "lose" the parts. If the HD factory doesn't make it, he doesn't mess.
Thanks for the note about the chainring; I kinda wondered about having an aluminum chainring.
I may just prep it with alcohol and spray it with Rust-O-Leum.

Typical. Recently one of my friends who works for a valve manufacturer told me a similar story. The company that did their plating shut down -- the owners said they could no longer maker a profit because of EPA demands. Took them a while, but they finally found a new plater -- at MUCH HIGHER cost.

Last update . . . done . . .
Given all the discussion, above, I committed to the Rust-O-Leum, carefully, and it turned out great!
Prior to spray painting, I went over the whole crank with acetone, then with alcohol, then with alcohol a second time taking care to remove fingerprints. Hung by a pedal, the paint was carefully sprayed.
What about nicks and boot scrapes? That's why black fingernail polish was made!
Thanks, again for the helps!

Fine for now, and I know you did a careful job, but you will find that regular spray paint does not stick well to aluminum. I found out. You need to use a special (aircraft) primer that adhears to the AL, then you can spray conventional paint over the primer. Back to your original thought: there's a reason why most AL parts are annodized, that is an electro-chemical process that grows an artificially thick version of what all AL does when exposed to oxygen: makes aluminum-oxide. The annodized finish is "attached" to the metal, the colors are created by adding dye to the chemical bath in which the part is submerged. And best of all: YOU can annodize in your own garage with a couple buckets and a 12 volt auto battery. Try doing triple chrome plating at home, there's a good reason that the EPA is shutting it down, even tho I bemoan that, too. Of course, preparation is still crucial, and practice makes for better results, but google for home-annodizing instructions and take a look. Always use caution and wear eye protection, as simple as it is this isn't for children or drunks...or drunk children.

Point taken. I would never use an "ordinary" spray paint for this application. I used Rust-O-Leum, which (I believe) has an additive that allows adhesion over oxides. True, Aluminum behaves very differently from Iron. Does anyone out there have any experience with Rust-O-Leum over Aluminum?

In my book Rustoleum IS "regular spraypaint", it's just an enamel. Back in ancient times, the "secret ingredient" of Rustoleum was...oil. That's where the "oleum" in the name is from, and it was just an oily enamel that was supposed to keep the water away from the steel, preventing rust. Todays Rustoleum is probably not so oily, but it's not got anything to provide positive bonding to AL, neither does Krylon (an enamel-lacquer hybrid), or any commercial acrylic or alkyd enamels or lacquers such as DuPont Centaur. I had access to a spray booth and a shop that stocked loads of House of Kolor automotive lacquers, as well as polyurethanes, and I painted a few of my own frames after work hours and helped many friends and co-workers with theirs. One guy I did almost all the work on had a Cannondale that was given a very careful prep and very meticulous primer and 2 part finish spray with synthetic lacquer and clearcoat...it looked great when done. About 2 weeks after he had been riding it, he said "dude, it's chipping all over, and I've been taking real good care of it, what's happening to my beautiful paint job?" So I starting by asking the shop foreman, a Swiss gentleman not known for his sense of humor, and he gave me a short lesson about paint on aluminum, most of which I've forgotten (solvent fumes are murder on short term memory and other brain cells) but the jist of it was: "special binding primer for AL".... which I now share with you. That's not to say you won't luck out and get some good results some of the time, I certainly have done, but as often as not you may put in HOURS of labor on a 'Dale or a Klein and be cruely disappointed.