Blackening Stainless Screw Heads

[sign216]

What's the best way to blacken stainless screw heads?

These are oddball metric, so it's difficult to replace them w regular carbon steel screws.

Maybe acid etch, and then paint or a blackening pen? Idk, what's the board's experience?

Joe

 

[HKGuns]

I usually heat them up to the point where they are naturally blue, then apply cold blue, polishing afterward. Brownells Oxpho blue seems to work decently. But it won't generally be perfect on stainless.

Interested to see what other folks do as well.

ETA: Yes, degrease them first as noted below. I usually use Acetone.

 

[.38 Special]

The first thing I'd try is washing with dish soap and water, and then applying a cold bluing pen. This doesn't always work, but does work a surprising amount of the time.

 

[BBBBill]

Ther is bluing that will work on stainless, but too expensive for the hobbiest to purchase for one or two guns. Oxynate 84 is thw name if I recall correctly.
Probably best to find a smith or refinisher that has that set up in his shop and ship the screws to him to do.

 

[sign216]

HKGuns and 38Spec,
Thanks for your tips for trying cold blue; degrease, heat, and then blue. I'll give that a try.

BBBill,
I checked, and Oxynate84 does blue stainless, but as you said, it expensive. For the professional gunsmith. I might go there if the cold blue efforts don't work well enough.

Thanks to you all,
Joe

 

[sign216]

Post Script: The technique I was originally going to try was acid etching the stainless screw head, and then painting or duracoating over that. Any experience with that idea?

Or try the cold blue after acid etching.

 

[HKGuns]

I've never used Duracoat, I'm set up to do cerakote for small items like the "Ghost Guns" I mill myself. If you actually need it black duracoat may be your best option. If it is a one of a kind screw I'd probably just try the bluing method I describe above. If you have a hundred of them, experiment a little, you may come up with something better.

 

[doubleh]

It would depend on the class of stainless the screw is made from. Acid will do nothing to 316, the class I am familiar with. The only piece I ever saw with etching was a piece of 1" pipe that had long been in service in sulphuric acid and it was small. The 4 classes are not truly stainless, only stain resistant, and harsh enough conditions will damage it. I just use a sharpie to color them. It will wear off of course but is simple to recolor. Duracoat, ceracoat, or even Krylon fusion paint will last much longer if you want to put in the effort. Light sanding will make the fusion adhere better. As paint goes it's one of the tougher ones and easy to apply. Spray it on, let it flash off for several minutes, no longer than thirty, and give it another coat.

 

[sign216]

The Krylon fusion paint is sounding good. Perhaps with a metal etching primer they use for cars. I already have both, so it's an easy try.
Before that, I'll try cold blue on one, since I've already got the blueing. With the degrease/heat/etc, we will see.
If they all fail, then it'll be Duracoat or Ceracoat, but I don't have any, so it'll try the other stuff first.

Thank you all.

 

[Tilos]

The Krylon fusion paint is sounding good. Perhaps with a metal etching primer they use for cars. I already have both, so it's an easy try.
Before that, I'll try cold blue on one, since I've already got the blueing. With the degrease/heat/etc, we will see.
If they all fail, then it'll be Duracoat or Ceracoat, but I don't have any, so it'll try the other stuff first.

Thank you all.

Something I've done to finish screws is coat/paint them in place.
This eliminates the chance of marring the finish during installation.
I use a leather punch to cut a screw-head size hole in a piece of tape, install it as a mask over the screw, and coat/paint the screw head.
That has worked for me,
.

 

[Blue68f100]

I got a kit from Caswell SS Blackening decades ago. It works some what but did have a surprise side effect. On some type of SS it could give you a demascus look, macro etch. Something to consider, I was thinking about turning my SS 1911 black at the time.

 

[sign216]

Tilos,
Thanks for the tip on coating them.

Blue,
I'll keep that kit in mind, if the other methods fail. Thanks