What is Do-It-Yourself Cold Blacking? | DEAI NEWS
Sign in / Join

What is Do-It-Yourself Cold Blacking?

A recent method combines a proven cold blacking process with an ion exchange filtration unit to overwhelm any opposition to blacking your own parts. Let’s take a look at the trend to bring blacking into the workshop.


Metalworking shops encounter a wide range of issues-many which impact the main business of cutting metal. One of the main issues is proper finishing of workpieces by blacking. For a long time, the only blacking option availableforworkshops required running a hot oxide line. With the increase in environmental regulations and concern for worker safety, this caused many workshops to remove in-house blacking in favour of sending the work out.

Then, in an effort to please customer demands for quick delivery, zero-defect quality standards and to qualify for process certification programs such as ISO 9000, lots of workshops brought previously out-sourced operations (like blacking) back home to maintain control and internal cold blacking hasnow become the system of choice for many workshops. Businesses that have set up blacking lines using the cold process have found the system safe and regulation compliant. Bringing the process home has let these shops take direct charge over part delivery schedules and the finishing process.

What is blacking and how does it work?

Blacking is a finishing process that chemically coats the surface of a ferrous material. It establishes a durable barrier against humidity and corrosion. Blacking is mostly done in a batch operation and is usually less expensive than other options such as painting and plating.Blacking uses a chemical solution that holds to the surface of machined metal (in all crevices). It forges a porous base that bonds chemically with the workpiece surface.

Aside from the aesthetically finished look, the black deposit on the workpiece is in reality the means to hold a sealant, which is the business end of blacking and what it’s all about. Ever hear about a chemical blacking kit?

Why do blacking yourself?

Let's pretend that your workshop has a requirement to blacken parts. It could be for protection from corrosion, to coat a finished surface, but preserve dimensional accuracy, or just to make the part look good. You will have two choices for applying black oxide to workpieces--out-source or in-house. Control is the question. Most contract blacking outfits build up large batches of work so as to maximise equipment utilisation. Thismakes the process more profitable, because large batches make running the line more effective.

The problem for you is that delivery of your work can take days or even weeks, depending on where your jobs fall in the vendor's schedule.It's tough for a shop to meet its delivery schedule if the delivery schedule for work sent out is variable.

How Is It Applied?

There are two methods used in applying black oxide. The oldest is the hot oxide method. It's been around for 60 odd years or more. Cold blacking is the second method and, as the name implies, but works at room temperature.

Cold blacking is definitely here and set to stay.

Leave a reply