Black Oxide Coating
 

I have some parts that I'd like to do in black oxide. I've never done this before. Anyone have advice?

Make sure they are clean. The parts will look better if they are media blasted.

Ok. All parts will be bead blasted first.

Would you have any idea why I can not post any threads?
The administrator is not returning my emails.

Assuming you mean black phosphate, it is very easy. It has been a while since I tried it but basically I think I just added some solution and boiled the (bead blasted & clean) parts in a mesh strainer. Then hit with WD40 after to remove any moisture.

Yes. I've just always heard it referred to as black oxide. It's really etching not coating I guess. The way they treat fasteners to inhibit corrosion.

Black oxide and zinc phosphate are two different finishes.
I do this for a living. just wanted to clarify. There is no zinc in a black oxide coating, it is a ferrous oxide applied to the surface.

I don't think most hobbyist are actually applying a real black oxide coating since it's rather involved for a garage setup. Most are using various types of "blackening" processes which give the look but not the depth of protection of real black oxide coatings.

The coating is not a durable coating, without oil it will rust.
I use Eastwood's zinc phosphate paint, it looks factree, and is more durable
than oxide. You can oil it for that factree sheen.

I've used a dark Manganese coating to imitate black oxide. Looks passable but isn't as dark as proper black oxide.
I only coated the barrel in this photo.


https://forums.maxperformanceinc.com...9&d=1625610059

Been using the Black Oxide plating solution from Caswell Plating for a while now and parts have turned out great. Like painting, it's all in the part prep work. You will have to remove the rust by media blasting or other method. The trick to getting the parts to look good is buffing the parts with a brass or wire wheel, giving them a shiny sheen. Also clean them with a solvent and rag before dipping in the solution. They go into the plating solution no more than 5 minutes. They get rinsed off, air dry but then you have to spray an anti-rust type coating on them, which actually gives the parts a deeper black sheen. Good luck!

Here is a suspension component I did in zinc phosphate (TOP) much lighter in color than Manganese.

I get my zinc phosphate and manganese phosphate from this guy: https://www.palmettoenterprisesparkerizing.com/

https://forums.maxperformanceinc.com...0&d=1625610347

I used Shooter Solutions Rugged Gun Blue to replicate the black finish on fasteners but not sure it's available anymore (web site says it is temporarily down). It came in a kit with the solution and an oil. Like Dataway's example, there are other inexpensive "cold bluing" products readily available online (Brownell's, Blue Wonder, Van's) but I haven't used them.

https://www.ktgunsmith.com/rugged_gun_blue.htm

If your fasteners are rusty, overnight in Evapo-Rust will work miracles and is very safe.

I did NOT bead blast but would typically soak the fasteners in a concentrated solution of Drano overnight to clean. Obviously, wear gloves and some eye goggles..

If your fasteners are plated, you'll need to strip the plating first... these cold bluing products only work on bare steel.

The bluing (blackening) process was simple, fast, and delivered a very uniform and black finish.

The oil in the Shooter Solution kit was some type of "air hardening" or "drying oil" that left a heavy film. You could use Linseed or Tung oil which both harden to a varnish that will be more durable than a gun oil or similar lubricant.

Zinc or Manganese phosphate is a decent middle ground between cold bluing/blacking and factory type coatings .... but it does still involve some chemicals and heat. The parts pictured above had to be "boiled" in the phosphate solution. Had to build a special SS trough for the barrel. Typically bead blasting is the only way to get them clean enough and present a proper texture for the process to take nicely and hold oil in the future.

If you search YouTube there are many good videos for black oxide coating, very helpful for me to see the process, materials and supplies suggested.

A few I really liked on how to chemically phosphate bolts, the first being rather long but very informative, the second a update, the third is newer.

https://www.youtube.com/watch?v=iOciisXubsk

https://www.youtube.com/watch?v=rEtgrwhR4Qg

https://www.youtube.com/watch?v=TFfJwNvK1iY



Frank

Evapo-rust is impressive! I need to try vinegar. Have read a few times that it works too.

I'm gonna order some Caswell black oxide solution. Thanks for all of the good info!

black oxide
 

I think that the phosphate coating is also known as Parkerizing. Billk