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What purchases and/or training is needed to do black oxide in house?

Our company rebuilds used machinery. We send many parts out several times per week to have black oxiding done to them. We would like to know if this is a process we can do in our own shop. Most of the parts we need black oxiding done we need same day, therefor do not have the time to send out. Can you tell me what needs to be purchased so we can complete this process in our own shop?

Thank you,

Traci Trimberger
- Racine, Wisconsin
2007

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Hot black oxide is a rather straight forward process and does not run into too much grief from the environmental folks IF it is set up and maintained properly. Incomplete records probably cause more fines that boo boo's do.
Commercial equipment and solutions are readily available.
CAUTION: You have to add water periodically and if you add it to a 250F solution, you can have it blow up in your face.
Call or email 2 or 3 vendors requesting complete information on a small black oxide system including tanks, solutions and operations. The more information that you give them, the better the reply will be.

You may choose not to do this, once you find out what the environmental requirements are.

James Watts
- Navarre, Florida
2007

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Traci,

If I were you I would only ever let the experts near a black oxide process, especially if they are already doing a good job for you.

If you really want to set up your own process be aware that you will be introducing very hazardous chemicals into your workplace and that these chemicals will then be used at high temperatures. Also when maintaining your solution you come across a unique number of other hazards.

Add to this the fact that you will have to get licenses to run the process and will then have a hazardous waste to dispose of (the EPA isn't going to let you just wash it down the drain) you have to ask yourself "Is it worth the effort and cost?"

If it is then get the advice of a consultant with experience with black oxide, he/she will be a much more reliable source than taking advice on setting up a line from a free posting site such as this.

My best advice though is to leave it to the experts.

Brian Terry
Aerospace - Yeovil, Somerset, UK
2007

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2007

A few more comments:

A general description of the equipment, processes and dangers is in MIL-DTL-13924 [on DLA] COATING, OXIDE, BLACK, FOR FERROUS METALS and MIL-HDBK-205A PHOSPHATIZING AND BLACK OXIDE COATING OF FERROUS METALS.

Hot black oxide lines normally include hydrochloric acid for pretreatment (and rework), requiring an acid-resistant room & fume scrubbing. Consider using a slower acting but less volatile acid.
Heating is a significant operating cost, but don't be induced into using a room temperature blackening (selenide or sulfide) process.

Two vendors within a 1-hour drive: EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser]. in New Berlin & John Schneider and Associates, Inc. in Mequon. Heatbath and Luster-On Products are additional black oxide vendors. Discuss your requirements & options, decide whether worth doing and, if so, get a turnkey set-up including all necessary EPA, OSHA and process instructions.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.