Letter 033

How to finish stainless

-----

Greetings from the Northwest,

I'm trying to find some information for a friend at work on how to finish stainless. We do a lot of custom fittings, rails, bow tubes, etc. Is there any quick and easy way to bring the material to a high polish?

We've been sanding to #600 and buffing. My friend Tom has heard about electropolishing is it feasible? Would appreciate your thoughts.

Dan Britts

Probably no 'quick and easy way', but electropolishing may be faster and easier, and it will give you a more corrosion resistant and all around better product.

You need to find a job shop that offers electropolishing of stainless steel to do some sample parts for you to find out what happens. So check our Directory of Jobshops, or spend some time with the Yellow Pages calling plating shops until you find one that offers electropolishing.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Electropolishing in general is a fairly tricky operation requiring racking, specialized equipment, strongly acidic solution, a lot of expertise, etc. But if the production volume is high, it may be well worth the expense of setting this up. Cheaper options would be mass finishing, such as vibratory with appropriate media (good for small parts), etc. On that and other processes you can get a lot of useful information from the MFSA.

Another option would be bright dipping (chemical polishing), but this process generates a lot of acidic waste.

"PlaterB" Berl Stein NiCoForm, Inc. Rochester, NY

The least complicated way is chemical polishing of the stainless steel.

Many of the major chemical manufactures have the technology to accomplish the polishing with very little difficulty. Electropolishing is good, but very difficult to master, requiring a major capital investment and the solutions are pretty nasty!

Richard Zuendt
- Garfield, New Jersey

-- We are a company in California that deals with a lot of stainless steel products. We have recently developed a new product that is an investment casting made of 316 Stainless. I explored electropolishing as a possible finish for this part and found it to be very impressive. We have two parts that are approximately one pound a piece (very sizable parts). I sent these parts out to be electropolished and they turned out fantastic, almost a mirror like smooth finish. Remarkably, there are quite a lot of companies in the west that will do electropolishing and as far as cost it seems to be much cheaper and easier than chrome plating. Evan Boyd -- Dan: We offer a free sample service to qualified buyers, and you will find an "RFQ" form on our web site for a free estimate of the capital cost. We provide a complete service for the chemicals, equipment, and process know-how required. We also sell the "Hydrite" line of chemicals mentioned by one of the respondents to your letter. Chemical polishing may be an alternative to electropolishing in some low-end applications, but the finish is generally not acceptable for boat parts or other products requiring a "mirror finish". If you want a general look at electropolishing without obligation, consider attending one of our seminars in Charlotte. You will receive a broad education in the process and a valuable reference manual for developing your application. A summary of the seminar topics is listed on our web site. Regards, Ed Bayha Metal Coating Process Corporation Charlotte, North Carolina, USA