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diy black oxide coating

D

ddo

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Oct 29, 2012
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Richland
Was thinking about trying a little black oxide coating at home. Anybody ever done this? Ill start with scrap metal to see how it works and am hoping to get to point of using it to restore a few wedges and putters.

Sounds like the process works with a caustic solution boiling at 275-300 for 15 min or so. Thinkin i can cook it under a hood on a hot plate. Have access to a digital scale and more than enough chemical background, just wondering if theres some practical experience out there.

Anybody have experience with at home finishes like this? Besides black oxide, chroming or anodizing are there any other ways to form a nice looking finish?
 
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nine4gmc

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Mar 24, 2012
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Dallas
In for info, I used to do brush plating but would like to know more about Black Oxide etc.
 
S

slip knot

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Mar 22, 2010
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Texas gulf coast
Look at some of the gun finish's .They do a lot of different oxide coatings. I was looking up some rust blueing a while back and found all sorts of vids
 
Z

zkling

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Jan 23, 2007
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16,939
First off, black oxide is for steel. Anodizing is for aluminum. DO NOT try to color aluminum with a black oxide solution. It will destroy your part.

Yes, I do a bit of gunsmithing on the side. In the firearms community black oxide is referred to as bluing.

PLEASE USE CAUTION this is extremely dangerous if spilled. This is not me telling you how to do it. I take no responsibility.

Basically you want KnO3, NaOH and distilled water. I will have to check my book, but IIRC it is 1 part KnO3, 2 pats NaOH and ~7 parts water BY VOLUME. Bring to a slow boil ~295°F in a NON ALUMINUM PAN.

Make sure part is clean and dry before going into the solution. Let soak in solution till part reaches desired color (~10-45 minutes). Depends on temperature and alloy of steel of base metal. Then submerge in hot distilled water. Remove, oil and let cool.

Note, the depth of blue color is dependent on the polish you put on the steel beforehand. The lower the polish, the blacker the outcome will be. The beautiful blue luster on the old colt pythons and the like was a result from master polishing to a mirror finish.

I just got finished doing some parts this past weekend.

As slip knot said, rust bluing is a more traditional alternative. It produces a better result than hot bluing, but is MUCH MUCH MUCH slower and tedious. I can blue and entire firearm in a few hours with the hot method. With slow bluing I am looking at roughly a week minimum. However it has specific applications where hot bluing cannot be used.

Real chrome plating is a very nasty process. I wouldn't even want to try that at home.

ZRX61, I think what you are referring to is case coloring.
 
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hallboyone

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Feb 26, 2013
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Location
North Carolina
As a matter of a fact, I have done some misc. metel finishes. I am refinishing a gun and I was trying to decide how to finish it. The first thing that i tried was the hot bluing. You can get the chemicals from Home Depot in the form of stump remover (potassium nitrate, I believe) and %100 lye drain cleaner and lastly distilled water. You will have to check the exact ratio's for the ingredients but that is what I used. I made the batch to small so the color wasn't even because the temperature wasn't even either. After that first batch I discarded the idea because it was too complex and caustic. For the gun I actually decided on rust bluing. It is a really a cool process an it is how they did it between 'browning' and hot bluing. Basically you give the steel an even coating of surface rust and then you boil the steel to convert the red oxide (the rust) to black oxide. From what I have read rust bluing is the most durable method of bluing. You might do some research and really look at this website.
http://www.finishing.com/
I've also anodized in my garage. Anodizing is a multistep process that starts out with a thorough polish and clean. Depending on the finish desired you can either go really fine with the finish or leave it a bit courser. No matter what you chose to do, however, a clean, grease free finish is essential. The next step is to place the the aluminum pieces in the in a lye and distilled water bath. This eats the aluminium oxide off the surface so you start out with fresh aluminium. Then what I did was hook the piece up tho the anode of a 6 amp MANUAL charger and the cathode up to another piece of scrap aluminum. both pieced are then lowered into a %15 sulfuric acid bath (battery acid is %30) and the charger is plugged in. Bubbles should start to form over both poles but mainly around the cathode. What is important though is timing. A simple formula to determine the amount of time needed is 720 amp min. per square inch. So if you have a charger running 6 amps and the pieces 12 sq. inches then the piece need to run for several hours. This process creates pours in the surface of the aluminum so when you remove the pieces and dye them the dye has some ware to go. To dye the parts i used RIT dye and put it in hot water. Play around with some scrap until you get the color that you want. The you seal the pours either by boiling the piece in distilled water or you buy a product from caswell made for that purpose. Then you are done. Let me know if you have any more questions and I will try to answer them.

Note: I am not a pro. I am just a guy playing around with some methods of finishes so don't rely on me %100. There is plenty of material out there.
 
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D

ddo

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Oct 29, 2012
Messages
153
Location
Richland
Great answers. Thanks guys. Gonna be enjoyable to use some of the job skills as a hobby. Think i might give it a shot on some old ridgids as well where the paint has flaked off.
 
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