DIY Metal Blackening


If you work in any manufacturing environment, you will have likely heard of the metal blackening process. What you might not know is that it is perfectly possible for you to treat metal objects and equipment yourself.

With the right tools and equipment, you could be on your way to producing blackened metal. Here we will show you how.

Why Do It in House?

If you own or run a tooling or manufacturing business, chances are you will have a lot of products that need to be chemically treated. This could be to provide an element of aesthetic appeal or to improve their resistance to humidity or corrosion.

Your options would either be to find a company who could batch blacken your products through electroplating or other chemical treatments, or you could do it in house.

Your decision would likely be based upon your production timescales, the likely cost of outsourcing this process, as well as guarantees on quality and finish. It might be beneficial to run a cost or scenario comparison, comparing exactly these parameters.

Hot or Cold Blackening

If you’ve decided to bring your metal blackening needs in house, you have two options. Cold or hot treatment.

A hot treatment makes use of a caustic soda bath, continually at a boil with the use of gas burners. Being anywhere near these baths would of cause be unpleasant as it can be a messy and dangerous process. Most hot treatments have been superseded by cold treatments.

Cold treatments on the other hand make use of warm chemical solutions which are much safer and can be far more time effective. Gloves and eye protection will be required for cold black oxide but it is considered to be a far more desirable solution.

The Process

You will require anywhere between 6 – 8 individual baths. These baths should remain at room temperature and contain;

  • Alkaline cleaner
  • Water
  • Blackening compound
  • Sealant

You will need to physically place each metal object into each liquid bath in turn. The duration required for each stage will vary, but anywhere between 3 and 5 minutes is the norm. The whole process from start to finish should take around 10 to 15 minutes per item.

To automate the process, you could construct a production line where metal objects are placed into these baths automatically. The setting up of this production line will be costly but might pay for itself if you have a lot of metal to treat.

Discharge and Disposal

The waste solution from this process cannot be poured into drains and should be disposed of responsibly. This will likely add additional cost to the process unless you can setup an ion exchange which can remove any harmful particles from the waste solution.

If all of this sounds like too much trouble, there are other solutions. Making use of a metal blackening expert is one such solution which could save you time and money. There are several suitable companies around the country so you should be able to find one which is located near to your workshop or factory.

The benefits of metal blackening are too good to pass up on so whether you DIY or employ an expert, we think you’ll agree that it’s well worth the cost and time.