View Full Version : Hot blueing at home?

June 1, 2011, 07:31 PM

Is there a process I can do at home on an outside burner that will result in a "blue" (not black) finish on a 1911 slide? I'm looking for something like the Colt royal blue.

Thanks for any guidance.

June 1, 2011, 11:20 PM
It takes a good blueing smith to do that, I very seriously doubt you can do it yourself.

June 2, 2011, 06:17 AM
It IS possible to do a bluing job yourself--even hot tank bluing--but there are some things you must be aware of:

1. The equipment to do it properly is expensive. Brownell's does sell a complete bluing outfit--but the beginning equipment will set you back at least $900 or more.

2. In a bluing job, metal prep and proper flaw removal is EVERYTHING. You'll need more tools for that, so bargain in another $600 or so--at the very least.

3. You will find it VERY difficult--if not impossible--to duplicate Royal Blue. The original Royal Blue was known as carbonia bluing, and I believe it involves the use of arsenic.

4V50 Gary
June 2, 2011, 08:06 AM
Buffer wheels. You need a grinder that has buffer wheels.

Bluing tanks. You'll minimally need four of them: degreaser, bluing, neutralizer and then a rinse tank.

Space. You need your buffer in a space that if you lose a piece and it goes orbital, it won't take out the fish tank, a window or damage your car. You also need it clear so you can find the orbital piece once it lands. You also need space for the tanks. Oh, you also need clean water that doesn't have any minerals because the minerals will affect the salts. You also need gas (or propane) with which to heat the tanks and a good concrete floor that is coated to prevent the salts from eating up the floor. You also need a central drainage hole for any liquids to run down into.

June 2, 2011, 08:27 AM
If you do all the polishing prep work, many gunsmiths will do the bluing for a discounted rate. From what I've been told, the polishing is the hard part... Anyway it wouldn't hurt to ask around...


June 2, 2011, 09:20 AM
I don't think you would need to spend $900.00 to get everything you need. I've done hot blueing at home and had good results. Since you are only doing a pistol slide you will only need small tanks.
Ditto the prep work! I usually start by stripping the gun down and cleaning everything with a good degreaser. That's followed by a long rinse. Then into an acid bath (I use muratic acid) to kill the old blueing. Another long rinse and you can get started. At this point you should have all white parts with a dull finish. File, sand, machine and polish the parts to get the finish you want. What you see in the white is what you will get when blued.
Now you have to clean everything again. Every spot of oil, wax and grease must be removed. Wear cotton gloves. Any mistake here and you blueing will not look good.
You must use the time and temp recommended for your blueing to the letter. The fumes can be terible but contamination is easy if you do this outside. The pros use vent hoods. You will have to make some choices here.
Once the blueing is done you will neutrilize and then oil the parts.
Now you will be disappointed. The color will not be the same as the original finish. It will be good, but not like the original.
An other method is rust blueing. This requires a LONG time to finish. You allow the parts to slowly rust and card them each day. In about a month you will have a deep blue finish very much like the original. The problem here is that you can contaminate the parts and ruin the finish or let the rust go too far and ruin the finish. I've never tried this method, only read about it.
Black oxide (the finish you say you don't want) is a lot easier. With a nicely polished gun it gives a glossy black finish that is hard to beat for the backyard gunsmith.
Many of the older deep blue factory finishes can not be duplicated today. EPA regulations have put an end to them because of the gasses that are released.
Good luck with your project.

James K
June 2, 2011, 12:01 PM
Most of the color variation is the result of the degree of polish given the metal. But that Colt Royal Blue was a proprietary process that AFAIK has never been duplicated by anyone else.

As to Carbonia blue, it is not a DIY process and not feasible for any home workshop or even gunsmith shop. Back in 2007 on this site I wrote:

"The way S&W did Carbonia bluing (note the "i") was to hang the guns in racks in a revolving drum in a gas furnace that was heated to over 600 degrees and had the Carbonia chemicals put in. The process was part of the heat treatment, which is why it could not be repeated. Guns sent to S&W for refinish were hot tank blued. If true Carbonia bluing is used by restorers, I would be somewhat concerned about refinishing guns using such a high temperature process, but I guess those guns will be for show, not use.

The guns were not buried in bone dust and there was no oil quench, just normal cooling; there was no mottling and no color other than the old S&W blue. Carbonia bluing is extremely durable and long lasting, not at all like heat bluing which is only a thin color on the surface. Like other finishes, the polishing has a lot to do with the final appearance, and can be anything from a shiny black to a "brush blue". (S&W's trademark hammer and trigger case coloring was done in a cyanide bath with air bubbling, not by any charcoal or bone process.)

Contrary to what has been written, Carbonia blue was not developed by S&W and was not proprietary. The process was developed by the American Gas Furnace Company, which rather gives an indication as to how it was used. Since it is a trademark for a specific process, not just a generic term for case hardening or bluing, I have capitalized it here."


June 2, 2011, 01:51 PM
Many thanks to all. I may call Colt and see if they'll do it.

June 2, 2011, 06:59 PM
There is an excellent article on this subject in the Shooting Times that came today ! Belgian Blue is the ticket !

June 3, 2011, 07:10 PM
Colt Royal Blue is not a process like Carbona, it's a standard hot salts blue that's done after the metal is given the finest possible polish job.

Royal Blue was known inside the Colt plant as "the Python finish" because that's the first gun it was used on.
The only difference between Royal Blue and the bluing done on a standard Colt like the Detective Special is that the Royal Blue is polished to an extremely fine finish by a master polisher using very large, very hard polishing wheels.

There was an old saying that while other makers guns were being shipped to the distributor, the Python was still in the plant being polished.
Colt still does the Royal Blue, and they refinish guns to like new appearance.

If all you want is one slide re-finished, by far the cheapest way to get it done is to send it to Colt.

James K
June 3, 2011, 08:41 PM
Colt, like other factories, not only used hard wheels, but used shaped wheels. For example, a wheel might be shaped to exactly match the contour of the bottom of a revolver, trigger guard and all. That way, it was necessary to make only one pass to polish that entire area.

For a shinier finish, a gun could be polished on a smaller wheel with very fine grit, or even on a linen wheel with only a fine powder. But a high polish does not always add up to a blue (instead of black) color. In fact, the opposite is true because the blue color comes from light diffraction in very fine "scratch" marks. With just the right grit, you get a nice blue color; with finer grit, the color tends towards black.

I strongly recommend that anyone doing hot tank bluing experiment with different grits and different polishing techniques on scrap material before starting on a gun. There is a learning curve and it is a steep one.


June 4, 2011, 06:30 PM
And metal is totally unforgiving of slips.

June 10, 2011, 01:56 PM
Thank you all for your help and advice. I sure appreciate this forum!

T. O'Heir
June 10, 2011, 08:26 PM
"...central drainage hole for any liquids to run down into..." Um, no. You don't want any of the toxic chemicals going down any drain.
In addition to the expensive equipment, you need a room that has no other ferrous metals you care about in it. The bluing salts get into the air and will cause a layer of rust on everything ferrous.

July 10, 2011, 10:00 PM
This may be your best option for hot bluing at home<http://www.brownells.com/.aspx/pid=1105/Product/NITREBLUE_reg__BLUING_SALTS>. You will still need buffing/polishing equipment, degreaser, heat source,specialty thermometer and 1 gallon bluing tank.

James K
July 11, 2011, 09:19 PM
I do NOT recommend hot tank blue as a DIY project, and certainly not for one or a few guns. The cost has already been mentioned, but also it is VERY DANGEROUS. You are fooling with caustic salts at a high temperature. One splash can burn through to the bone before you can even think about it. You need protective gear like a heavy rubber apron and boots, goggles, gloves, a heavy cap and face shield. And a lab type douse shower that will dump gallons of water in seconds. And a place for that water to go.

Hot tank bluing in your kitchen? Some people claim they do it and it is easy. I hate to call folks liars, but they are certainly either misleading others or taking great risks with their own safety (or they literally don't know what they are talking about).


July 30, 2011, 07:40 PM
. One splash can burn through to the bone before you can even think about it. You need protective gear like a heavy rubber apron and boots, goggles, gloves, a heavy cap and face shield.I've done hot salts bluing since the mid 1970s and yes it can leave a nasty burn but I seriously doubt it can go to the bone. I have all of that PPE stuff but it stays hanging on the hooks in the shop(to darn hot to wear).Hot tank bluing in your kitchen? Some people claim they do it and it is easy. I hate to call folks liars, but they are certainly either misleading others or taking great risks with their own safety (or they literally don't know what they are talking about).
Stove top bluing is definitely a BAD idea! Not from a safety standpoint but because of the damage it would do to the stove and anything else near by. As for price,a complete set-up costs about as much as a quality gun safe.

James K
July 30, 2011, 09:07 PM
Hi, Jimmyray,

I have seen what happens when someone splashed caustic salts on himself, and it is not pretty. Please don't leave that safety gear hanging up, use it. I know it's hot, but getting boiling salts in your face and eyes is far worse.

Just to show how things can happen, I had a good friend who did a lot of bluing before OSHA, EPA and insurance rates practically killed small shop bluing. He had a habit of bluing M1911 magazines by polishing the outside, dunking them in a degreaser and tossing them in the tank. That worked OK; the spring was not affected and it saved a lot of time in tearing down the mags.

But one day he did that with a BHP magazine, not realizing that the follower is aluminum. The aluminum dissolved in the tank and the spring let go just as he was bending over the tank. He was, thank God, wearing goggles so his eyes were spared, but his face was scarred for life.

Again, PLEASE use protection.


July 30, 2011, 09:31 PM
I DO wear neoprene gloves,especially when adding water to the solution. It tends to get "reactionary".

Alex Johnson
August 4, 2011, 11:54 PM
I can think of many reasons that I would not venture into hot salts blueing at home, but you might give Belgium blue, or a traditional slow rust blue a try. In my opinion these are both better looking and more durable finishes in the end anyway (with the edge in durability going to the slow rust blue). In the end it is your metal preparation that is going to mark the difference between a high quality blue and a low grade one. I polish everything by hand and forget about buffing wheels.

July 6, 2012, 07:00 PM
". . . . . I've done hot blueing at home and had good results. . . . . ."

Dear dlb435,

I do need to blue my old airgun, so far I have search the good working bluing recipes with out a satisfactorily result.
Reading your reply in this topic brightened my hope again.

Please share your hot bluing recipe and its prcedures will you?

Thanks dlb435 please do help me.

July 15, 2012, 02:39 PM
I wouldn't bother with hot salt blueing in a home shop situation. It's messy, corrosive has all get out, can be personally hazardous and (most of all) it isn't necessary.

Folks should look into fast rust blueing. You can get solutions like Mark Lee, Brownells' and others. Their colors vary a bit; you should experiment to find what you like.

You polish to between 320 and 400 grit, clean the metal very well to remove any oils. You can start by using a degreaser on the metal with water, then acetone to follow up, or you can set up a hot water tank with Dicroclean or washing soda.

Then you swab on the blueing solution. Get as even a coat as possible, without any drips, runs, sags or misses. You then put it somewhere humid and warm (gunsmiths use a "sweat box" for this). After a 'fuzz' has developed on the metal (it will usually be brown/red in appearance - do NOT panic at this point), you put it in a tank of boiling water. If you have hard water, get distilled water for your boil-out tank.

You will then see the rust turn from red to black/blue.

After you've boiled the metal for 10 minutes or so, remove from the boil-out tank and card. To card the metal, you use de-oiled (or oil-free) 0000 steel wool or a .005" wire wheel at low speed.

You then apply another coat of the blue solution, re-sweat, boil, card, etc.

Do this six to nine times and you have a very nice finish.