Best Alternative to Black Oxide Finishing

A. Hi B. Zinc plating can be done in bulk in plating barrels, and this is the least expensive plated finish. It is available in clear-blue, yellow, or black.

A potential issue however is that it will surely require hydrogen relief baking after plating, and it is also possible that your components are too hard (too sensitive to hydrogen) for plating. Mechanical plating or dip-spin zinc-rich 'paints' are another possibility but they may be too expensive.

Is the black oxide coating unsatisfactory in some way?

Luck & Regards,

A. Hi Bryce. Hopefully a reader can help you solve the inconsistency problems in the black oxide process, but realistically, as Larry Durney explains in his "Trouble in Your Tank" [affil link to info/book on Amazon or on AbeBooks], it is very difficult for a reader to help a plating shop with you and I as middlemen because it violates most of the rules of troubleshooting, including "Walk the Line" and "One Boss" :-)

Black oxide has very little corrosion resistance, and most of that is from the oil or wax you use, so maybe trying some changes there will help.

It sounds to me like zinc plating with black chromate is a worthwhile upgrade, but maybe zinc-iron plating with black chromate would be better since the color is more robust (sorry, I don't know if it's more abrasion resistant). Personally I think you should look at that "shipping in bulk" and see if it can be improved.

Luck & Regards,

A. 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,

A. 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)

A. Try in-house, do-it-yourself room temperature blacking from (1) Hubbard-Hall, (2) Birchwood Technologies [a finishing.com supporting advertiser] (3) EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser] in Madison Wisconsin. If there are others, please forgive me

---

! 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
June 30, 2009

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

A. Hi Suraj. We need to know the application and the environment for a thoughtful answer, but zinc electroplating is inexpensive, corrosion resistant, and poses less risk of burns.

Regards,