Hot Gun Bluing?

I’m considering hot bluing (not cold or rust bluing) the frame, slide, mainspring housing, and magwell on my next build (or maybe Parkerizing). Does someone have suggestions on the process or a solid reference?


@Mosinvirus would be a great resource.



If you have the space, Brownells used to sell

This will give you an idea.

Check out the LEARN tab on the product page and download and read those instructions. I have also attached the files and links here for your convenience.

Here is the Brownells Bluing booklet:
076-200-040_Bluing_Booklet (1).pdf (2.6 MB)

Here is the Brownless article on traditional hot bluing:

And here is the Non-Hazardous Kit info:
076-200-595_Non_hazardous_Bluing_System_Kit (1).pdf (253.8 KB)

Parkerizing is my preference - easier, less setup, better surface for oil retention. However, cannot be done on stainless, whereas Brownells has one hot blue solution formula that will hot blue stainless.

My video showing how I parkerized my 1911 at home.


I also have considered hot bluing but after I researched some of the costs and the space and ventilation for doing it at my home shop I chose to not pursue it at the moment I have both a cold bluing and rust bluing set up now but haven’t begun to practice it as of yet


I had watched your Parkerizing videos with interest and have considered Parkerizing instead of bluing, and still might.

Brownells’ training material is a great idea. I knew they sell (or sold) the equipment, but didn’t think to read their manuals!


The hazardous hot salt bath is a concern. And ventilation together with personal protective equipment, is key.

I’m not sure the costs are that high? Where did you see them adding up the most? The bluing salts only come in big 40# or 50# containers which means I’ll need to have a neighborhood bluing party!


Just the cost of start up alone was enough for me to say no the link mosin dent was 3000 alone
You can diy for way less
I just chose not to pursue that at the moment
I dint have a lot of disposable income at the moment alimony and child support are killing me


@BobRock, people do make their own salt solutions. Lots of videos on the subject of DIY setups. I never personally did any hot bluing.

If i had to blue long pieces - rifle or shotgun size - I would go with slow rust blue because they can be done vertically in steam chambers (PVC pipe for example) rather than boiling tanks.

@Giantspeed sorry about alimony and child support. Been there, done that (though never alimony, thank God). Hang in there man.


Yes, the Brownells big rig is/was very expensive. My plan would be to get pots and pans from Goodwill or Wal-Mart. Since I would only be working on pistol parts, I can get away with much smaller “tanks.”

I, too, am sorry to hear about the alimony and child support and hope they’ll be over soon.


I may go the route of DIY bluing salts after more research on the subtle differences in chemistry I’ve seen.


If you’re only doing a single pistol, parkerizing can be done at home fairly simply. An effective solution can be made up from Phosphoric Acid(Kleen-Strip concrete and metal prep from HD or Lowes), degreased 0000 steel wool, distilled water and some Manganese Dioxide(found on Ebay). You can do the whole thing on a hot plate. I’ve tested the solution I mixed up on several pieces of sanded raw steel with good results. I’m just waiting on getting the frame/slide/grip safety/trigger of my FN 1906 sandblasted.

For bluing, which I will be doing on my CZ75B, all you need is a countertop deep fryer with an enamel tank and salts of your choosing. I’ll be going with Electrochemical Products Inc ‘Ultra-Blak 400-L’. One gallon, more than enough for a single pistol and then some is $17. Oh yeah, buy a candy thermometer instead of relying on the fryers temp setting and WORK OUTSIDE.


EPI also makes a room temperature bluing product that they claim gives a nice grey-black (not blue-black) finish.

Does anyone have any experience, good or bad, with that?


I don’t do a lot of gun refinishing work, but that Insta-Blak looks useful for many things.


The Insta-Blak 333 in particular? No. Other similar finishes? Yes.

Back in my days of spinning wrenches for money I tried all manner of ‘room temp’ solutions on the market to refresh the black oxide coating of my impact sockets and other tools. Nothing held up as well as the manufacturers finish(which itself wasn’t all that great). In the end I simply left them covered in oil and grease to prevent corrosion. IMHO, hot treating is the only way to go.


Is it not just another cold bluing solution?
All of them are done at room temp pretty much.
All of them work, but it is all about the depth of the oxide they form and its ability to retain oil.

I would like to see an unbiased comparison of hot blued and cold blued (using this product) surfaces on the same base steel, using the same oil after the fact, and have them subjected to a salt spray test. As well as abrasion tests and repeated salt spray.


In my experience that is the biggest difference between the available ‘cold’ or ‘hot’ finishes. I haven’t seen a cold method that ever matched the depth of traditional hot methods and therefore didn’t hold up as well to handling.


That is why I prefer slow rust bluing.


I have contacted EPI in hopes of them providing some sort of lab data to support their claims about room temperature bluing:

Insta-Blak 333, a giant step forward in the room-temperature (cold) blackening for iron, steel and powdered metal. It produces a super-deep rich blackness and corrosion resistance equal to hot oxide blackening without smutty rub-off problems of ordinary room-temperature formulations.

It sounds “too good to be true,” and you know what that usually means.

I may still be tempted to try it. A trial kit with their degreaser, activator, bluing solution, and water displacing oil is about $50 and should be plenty to do several pistols. If it works well enough, good. If not, it shouldn’t be too hard to redo the work with another process and only be out $50 and time.


I received an answer back from the President of EPI very quickly. Rather than paraphrase, here’s what he said:

I am a gun owner myself. I would not use Insta Blak 333 for a gun that will be used in the field. I have had some DIY’ers refinish old guns with Insta Blak 333 with outstanding results better than me.

Insta Blak 333 is a conversion coating of Cooper and selenium. Bluing is magnetite Fe3O4 . The Bluing offers more abrasion resistance then Insta Blak 333.

We have two choices for bluing, Kool Blak 225, it is safer no boiling caustic fumes, and the traditional Ultra Blak 400. With E-Tec applied to all three you get same corrosion protection.

That makes me lean toward the Kool Blak 225.