Cold Blue - Spraying?

Not sure if you could.

The way I would describe it is that it does stain the metal, but in the way watercolor would paper...

I think it's only good for small spots.

I’ve had much better luck with Oxpho over the years. Bare metal is best for matching consistent color.

Skylerbone said:

I’ve had much better luck with Oxpho over the years. Bare metal is best for matching consistent color.

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Same experience. The paste blue by Oxpho works much better

After I used it once the Birchwood Casey was tossed out.

It's a chemical treatment, not a stain or paint, so you need plenty of the liquid for it to work.I puddle it in scratches, or immerse small parts.

Many of the Stars — esp the small parts — are very hard or a funny alloy or otherwise don't take cold blues very well. They are middling common in war zones these days, and unlike other older pistols (russian, high powers, etc) when they get to e.g. the Idlib custom shops are more often plated or Cerakoted than re-parked or re-blued.

Be sure it's well degreased before starting either way.

I sand blasted and parkerized one. It was easier than I thought. Like stated above, the frame is harder than the slid and it took a little longer.

wmgeorge said:

Got a Star BM on order and wondering if the cold bluing from Birchwood Casey could be sprayed on with a good quality air Brush? I have used the liquid blue before with a brush and as I recall it went on kind of streaky.

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Apply each layer with a fresh cotton ball or a clean cotton rag piece, not a brush.
You are distilled water-rinsing and steel-wooling it after each application, right?
I heat both the piece and the bluing liquid to make the process go faster (about 120 deg).
I'm guessing the cold blue liquid will ruin your air brush.

Apply with the cotton ball as mentioned. Then rinse and dry and card each coat with 0000 super fine steel wool. Wipe with degreaser (the steel wool is slightly oily) and apply the next coat of cold blue. Repeat up to 3 or 4 times. If it's still blotchy after that then it's an issue with the metal.

As mentioned already it's a chemical reaction, not paint or stain or coloring. So put the airbrush down and step away....

If you want fast deep penetration of the cold blue clean & heat the metal parts. I use boiling water to heat the parts. Not too hot just hot enough to be hard to handle & you need to coat the metal fast by putting it in thick ziploc bags then dumping the whole bottle over the parts, zip the bag closed & shake to cover it fast. It may take a few times in the water to reheat & put back in the bluing solution to get it dark enough.
After you get it the color you want rinse it in water then put it in a clean gal ziploc bag & totally coat it with a good quality gun oil. Keep it coated for at least 12 hours so the pores of the metal can absorb the oil.
Here is a picture of a PSL receiver I did with cold blue.

I haven't found any cold blue that's better than oxpho, but it's still no hot blue or rust blue.Easy to
use though.

BCRider said:

....(the steel wool is slightly oily) ....

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Yes, thanks for the reminder. Or rinse the steel wool in acetone before use. Oil stops and "fixes" the blueing process.

Hmm, can you use wool daubers instead of cotton balls?

Don't see why not.

gobsauce said:

Hmm, can you use wool daubers instead of cotton balls?

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That is how I got the best finish; I believe that the ferrite in the steel wool helps catalyze the reaction, and using steel wool to apply also opens up the surface of the metal a bit. At least that was my theory as to why it worked so well…

wmgeorge said:

Got a Star BM on order and wondering if the cold bluing from Birchwood Casey could be sprayed on with a good quality air Brush? I have used the liquid blue before with a brush and as I recall it went on kind of streaky.

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I used the Oxpho cream and applied it with a Q-tip to the worn areas of my recently acquire Star BM. I used non chlorinated brake cleaner to degrease first. It worked very well.

Before


After


BTW, I love this little pistol

I’ve had much better luck with Oxpho over the years.

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For sure!

A gunsmith here sprays Oxpho blue. He has some other techniques that I don't know but they give a very good finish.
I don't know how durable it is vs hot blue, none of the post-Incident refurbs he did for me get a lot of wear, but they LOOK good.

This one had zero original finish, just surface rust. It’s survived 10 years or so of range use by multiple kids and adults but no real woods carry. Oxpho finish.

Edited to add: the “gills” on these rifles act to expel gas and gunk from the action, exposing this area to far more cleaning from me. While reliable, mine prefers to see no more than 300 rounds between cleanings.

BCRider said:

Apply with the cotton ball as mentioned. Then rinse and dry and card each coat with 0000 super fine steel wool. Wipe with degreaser (the steel wool is slightly oily) and apply the next coat of cold blue. Repeat up to 3 or 4 times. If it's still blotchy after that then it's an issue with the metal.

As mentioned already it's a chemical reaction, not paint or stain or coloring. So put the airbrush down and step away....

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D-grease the steel wool.
I usually put it in a glass jar with paint thinner and then shake well.
It can take a couple tries to get it clean.
Set the paint thinner aside in another jar.
The oil from the steel wool should separate out and you can pour off the now clean thinner.
I use a toaster oven or heat gun on smaller parts.

I was looking at my small spray set last night.
A lot of aluminum parts in there.
Blue chemicals tend to eat at aluminum pretty badly.
If you really want to try spraying, you may well need to replace parts in your spray gun with steel.
Probably a higher nickel type of Stainless.