52408

Best Alternative to Black Oxide Plating  

June 16, 2009

My company manufactures specialized test equipment in small quantities. In the past we have used black oxide plating on the various steel parts in the equipment. Unfortunately, at least in Northern California, black oxide plating is no longer available.

We have used black zinc plating as an alternative but the price has been high. For example, a 3" x 7" x 5/8" steel rectangular plate is costing us $4. each to be plated in lots of around 100, almost as much as the raw material costs us. In addition, although the black zinc plating looks good, we have occasionally had flaking of the plating, something that was never a problem with the black oxide.

Is there an alternative to black zinc plating that will give us a black appearance but be less expensive than black zinc? The test equipment is always located inside and generally is never wet with water but will sometimes get oil splashed on it.

If there are no plating alternatives that are black in color, is there a more cost effective plating that still has good appearance in a different color (ie silver or gold?).

Thanks,

Paul Pitchener
Product Designer - Brisbane, CA, USA

Hi, Paul. Zinc is the least expensive metal plating, although silver or gold might be a bit less expensive than black. Black oxide is apparently what you need and it is inexpensive, and I would be very slow to move to a more expensive and less satisfactory coating until I was positive that black oxide was impossible to get. Because the quantity is small you may be able to expand your geographical limits if necessary.

Regards,

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

Well Paul I find it rather hard to believe that you can not find anyone to do your bluing for you. Granted there are no plating shops up here in the Great White North that do caustic bluing but there is a good reason for that. The simple fact of the matter is that there is a gunsmith under every rock and bush that are willing to do caustic bluing for under $40.00 per gallon for small parts that require no polishing. The plating and machine shops finally stopped doing caustic bluing. They just could not compete. I would imagine the situation is much the same down there. I just looked at the California Yellow pages and there are 441 listings under guns and gunsmiths. I'm not a gambling man but I would be willing to bet a case of beer that there is a gunsmith within 15 or 20 minutes of your location that would gladly run your parts though for a small fee. I think you would be quite surprised to learn how much bluing gunsmiths actually do for machine shops. Gunsmiths are generally always a dollar short and a day behind in rent. I once made 500 small jackshafts for a local hobby shop that was selling them to little old men and ladies to polish rocks and model airplane parts with. Go through the yellow pages and start calling shops. :o)

Rod Henrickson     gunsmith Edmonton, Alberta, Canada

Try in-house, do-it-yourself room temperature blacking from (1) Hubbard-Hall, (2) Birchwood Casey, or (3) EPI in Madison Wisconsin. If there are others, please forgive me

Robert H Probert Robert H Probert Technical Services Garner, North Carolina Editor's note:        Mr. Probert is the    author of Aluminum How-To / Aluminio El Como

It should be noted that the cold blues are a poor replacement for caustic bluing. They don't offer the longevity of caustic blues. In fact they offer little more than 1/10th the protection of caustic blues. It should be noted that cold blues can be made to last longer with thorough cleaning and heavy waxing of the parts. Also cold blued parts should not be handled with bare hands as the acid in our skin tends to break the cold blues down relatively quickly. :o)

Rod Henrickson     gunsmith Edmonton, Alberta, Canada

Black Oxide is still readily available at many facilities in your general area.

Bill Grayson
Metal Finishing - San Jose