STAINLESS STEEL Blueing (or blackening)

Does anyone know how to "blue" or blacken stainless steel? I know that
from a cold chemical standpoint a mixture of Selenium Dioxides and
Copper Sulfate is the standard "cold blue" formula for carbon
steel....but how does one darken stainless? With chromium in the steel
the copper method seems useless and an acid preferable....has anyone
used chemical methods in stainless with success? What works?
Reply to
my 2¢
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Kinda makes you wonder why stainless steel firearms are usu. left bright, doesn't it?
Bob Swinney
> Does anyone know how to "blue" or blacken stainless steel? I know that > from a cold chemical standpoint a mixture of Selenium Dioxides and > Copper Sulfate is the standard "cold blue" formula for carbon > steel....but how does one darken stainless? With chromium in the steel > the copper method seems useless and an acid preferable....has anyone > used chemical methods in stainless with success? What works? > > >
Reply to
Bob Swinney
Remington used to plate its stainless shotgun barrels with iron, and then blue the iron (early '60s). There is black chrome plating used on stainless, and blackened nickel. Maybe there is more. The last time I looked was 20 years ago.
There is some other treatment for stainless that can produce colors, but I don't recall what it is. In any case, that was for some obscure industrial, or aerospace application.
Ed Huntress
Reply to
Ed Huntress
Stainless steel blackening is a standard service offered by some gunsmiths. It works by converting the chrome on the surface of the metal to chrome sulphide in a hot bath similar to the hot black oxide system used for carbon steel but with different chemicals.
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sells the all the stuff you need to do.
In case you don't want to go into the business, you could use one of the finishing houses such as
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if a gunsmith near you doesn't offer the service.
Randy
> Does anyone know how to "blue" or blacken stainless steel? I know that > from a cold chemical standpoint a mixture of Selenium Dioxides and > Copper Sulfate is the standard "cold blue" formula for carbon > steel....but how does one darken stainless? With chromium in the steel > the copper method seems useless and an acid preferable....has anyone > used chemical methods in stainless with success? What works? > > >
Reply to
Randal O'Brian
How does it hold up to abrasion, Randy?
Ed Huntress
Reply to
Ed Huntress
This has been posted before but Brownells has stainless steel bluing/blackening chemicals. If you've got a one-off, try to find a gunsmith that's already got the setup, it takes some messing with to get it working right and you really don't want to invest in a bluing setup just for a one-off, not to mention the cost of neutralizing the stuff once you're done with it. There used to be black chrome plating as well, haven't seen anyone advertising that in awhile. An alternative would be a powder-coat job in your choice of colors. A method used in the past on Winchester stainless steel rifle barrels was to electroplate the barrel with pure iron and then blue that. Or you could just go get a wally-world can of flat-black spray paint and have at it. That's about all I'm aware of.
Stan
Reply to
Stan Schaefer
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I used to make my own printed circuit boards at home using ferric chloride as the etchant. I have a pair of polished stainless steel hemostats that I used to fish parts out. They are still a dark matte grey after 20 years. I don't know if it was the ferric chloride or the copper in solution or what, but something definitely stained the stainless. The resulting finish is also pretty durable.
Doug White
Reply to
Doug White
I don't have much personal experience with it, but friends say it is about the same as regular hot blued carbon steel.
Randy
Reply to
Randal O'Brian
Back in my aerospace processing days, black oxide on SS was done with a fused salt process. As the name implies, certain chemicals are melted at around 950 F. to provide the blackening environment, not something you want to do in a home shop.
Ed Angell
> Does anyone know how to "blue" or blacken stainless steel? I know that > from a cold chemical standpoint a mixture of Selenium Dioxides and > Copper Sulfate is the standard "cold blue" formula for carbon > steel....but how does one darken stainless? With chromium in the steel > the copper method seems useless and an acid preferable....has anyone > used chemical methods in stainless with success? What works? > > >
Reply to
Ed Angell
If you heat 300 series stainless steel to a red, it will turn dark, almost black, when it cools.
Reply to
Tom Stovall

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