Hot bluing in bay area?

[sierratangofoxtrotunion]

Anybody know of a place in the bay area (preferrably east bay) that can do hot bluing in-house? Not I take him my parts and he sends it out to Timbuktu and I get em back a month later... but rather he has a shop and he does it there, or maybe its some company and they do a lot of different plating stuff or whatever and also do hot bluing?

[sierratangofoxtrotunion]

buuuuump?

[Wyatt]

Yes, a number of places do "Balck Oxide" and it is cheap but you must take note that the acids used to strip and activate the metal for blackening could affect the temper.

[m24armorer]

I haven't torn my tanks down yet, what are you looking to get done.

BTW, Wyatt how did you come to this conclusion?

[Wyatt]

Which conclusion?
Black Oxide Mil-C-13924 is the process of what is commonly called "hot bluing".
http://docimages.assistdocs.com/watermarker/transient/2B5636F400374EEC9EE97BF89F129682.pdf see paragraph 3.10 I have seen failures and I have seen the prevention of them.
Ask me how I know? :ninja:

[huskydog]

American Blueing Company 510-799-4998

Located in Rodeo (Near San Pablo and Richmoned)

[metalhead357]

Which conclusion?
Black Oxide Mil-C-13924 is the process of what is commonly called "hot bluing".
http://docimages.assistdocs.com/watermarker/transient/2B5636F400374EEC9EE97BF89F129682.pdf see paragraph 3.10 I have seen failures and I have seen the prevention of them.
Ask me how I know? :ninja:

Makes SOME sense but then again...wouldn't the hot tank have to exceed 500 degrees before you need to worry about temper?

[Wyatt]

It's not the black oxide tank that causes potential , it is the HCL which can cause hydrogen to become trapped at the grain boundary. Relief is performed by a low temperature bake for ~3hrs.

This is how i understand the mechanism, it works for me as i perform the process quite often. Do as you like, I don't like to take chances and will do what i can to prevent failure.

[metalhead357]

Ok, that makes a little more sense, I was thinking the temp alone would cause the tempering problems.

[Wyatt]

Makes SOME sense but then again...wouldn't the hot tank have to exceed 500 degrees before you need to worry about temper?

I give you the military specification and it only makes SOME sense? :)
Lol, it's cool. I've been working with metals for a long time.

[metalhead357]

I give you the military specification and it only makes SOME sense? :)
Lol, it's cool. I've been working with metals for a long time.

LOL! no offense meant, I just worked in metal a LONG time ago, but never coatings/processes, finishes, etc. I was thinking Hot tank....Too Hot:confused: NOT trying to impune yer' experience; just trying to get info from it;)

[Wyatt]

:grouphug: None taken.

[m24armorer]

Yes, a number of places do "Balck Oxide" and it is cheap but you must take note that the acids used to strip and activate the metal for blackening could affect the temper.


I have never ever used a acid bath to strip or activate anything that hit my tanks in 25 years. If you want to dip someones Weatherby for the process you use, fine.

Mine go's like this:

The Basics of Black Oxide MIL-C-13924]

Class 1: Alkaline oxidizing. For wrought iron, cast and malleable irons, common carbon, and low alloy steels.
Class 2: Alkaline oxidizing. Use on certain corrosion resistant steel alloys tempered at less than 900°F
Class 3: Fused salt oxidizing. For corrosion resistant steel alloys which are tempered at 900°F (482°C) or higher.
Class 4: Alkaline oxidizing. For other corrosion resistant steel alloys.

What is it?
Black oxide is a conversion coating, formed by a chemical reaction, produced when parts are immersed in an alkaline aqueous salt solution operating at approximately 290 degrees F. The reaction between the iron of the ferrous alloy and the hot oxide bath produces a magnetite (Fe3 O4) on the actual surface of the part. It is also possible to oxidize some non-ferrous metals under suitable conditions to form black oxides. It is possible to apply black oxide at room temperature, however it is not possible to achieve all of the benefits available from the "hot" oxide process. The cold black oxide process routinely shows color variation from part to part and the black material frequently rubs off in your hands. The cold process does not meet military or automotive specifications. Therefore the remainder of this information addresses the "hot" process.
How is the process performed?
The five basic steps for the black oxide conversion coating are clean; rinse; black oxide; rinse; supplementary coating (after-finish). If rust or scale is present on the part, additional steps such as acid pickling or alkaline de-scaling may have to be added before oxiding. Neutralizing and/or further rinsing may be necessary on assemblies and parts with blind holes to eliminate "flowering" or bleed-out. Black oxide cannot be produced over plated parts (zinc, nickel, chromium, cadmium, phosphate). The plating must be stripped prior to the black oxide process.

You never (at least me) acid dip anything. Surface rust if present is removed very carefully by hand.

[sierratangofoxtrotunion]

Huskydog: thanks for the lead in Rodeo. I already go to Oakland for a zinc/yellow plating on other stuff, and Rodeo is actually slightly closer.

Wyatt: do I read it correctly that one can blue (black oxide) cast iron as well?