Brownells parkerizing instructions

Brownells parkerizing instructions DEFAULT

How To Parkerize Steel

M1911 pistol being parkerized.

Parkerizing: Applying an anti-corrosion and lubricating phosphatized surface treatment

Parkerizing is an electrochemical process that creates a protective iron-phosphate layer on the outer surface of steel. It protects the steel from corrosion and also increases its resistance to wear. The resulting surface is irregular on a microscopic scale. This produces a grey matte finish that holds water-repelling lubricant. The overall result of protection against oxidation and wear makes parkerizing superior to bluing for protecting guns.

First, some warnings

This is not the way to parkerize steel, but it is one way to do it. It might work for you. In the process, you might somehow manage to avoid burning down your house and poisoning yourself, your family, and your kittens. But I doubt it. Done correctly, this can still be downright dangerous. Don't try this at home.

Finally, I'm no metal-treating guru. I just helped a friend do this and I took the pictures.

CAUTION: Technical data and information contained herein are intended to provide information based upon the limited experience of individuals under specific conditions and circumstances. They do not detail the comprehensive training, procedures, techniques and safety precautions which are absolutely necessary to properly carry out similar activity. Always consult comprehensive reference manuals for details of proper training requirements, procedures, techniques and safety precautions before attempting any similar behavior.

OK, that should be adequate lawyer repellent...

Now for some background

My bullets, let me show you them.

Of course those are cases and not bullets. Cats are notorious for their poor grasp of technical terminology, not to mention their typing and English grammar....

Parkerizing is an electrochemical method of protecting steel from corrosion and it also increases resistance to wear. That's electrochemical as in chemical reactions which take place in a solution at the interface of an electron conductor (a metal or a semiconductor) and an ionic conductor (the electrolyte), and which involve electron transfer between the electrode and the electrolyte or species in solution. It does not mean that electrodes and wires are involved at all!

Parkerizing is the creation of an iron-phosphate layer on the outer surface of the steel, producing a grey matte finish that helps to protect from corrosion and increases wear resistance.

The protection is in two parts. First, the iron-phosphate layer itself is protective. Second, the surface is bead blasted before the parkerizing chemical bath, producing a surface that is irregular on a microscopic scale. This irregular surface is somewhat porous so it better holds lubricant.

There are several related techniques, but generally they involve a phosphoric acid (H3PO4) solution with key ingredients of zinc or manganese, with varying amounts of nitrates, chlorates, and copper, the solution being heated to 88-99°C, close to the boiling point. So, instead of the boiling lye of bluing, parkerizing uses boiling acid. It's nasty at the opposite end of the pH scale.

Different metal salts in the solution produce different colors of non-reflective finish:

Zinc     Light to medium grey
Manganese     Light to dark grey, or black
Iron     Dark grey to black
Military Handbook
Phosphate and Black Oxide
Coating of Ferrous Metals

Phosphating can interact with a coating of cosmoline over a period of years to produce a light greenish-grey color. I know that this sounds like an odd thing to mention, but the elusive green tint is the Holy Grail of the Garand restoration community because it is what is seen in WWII-era M1 Garands that were subsequently stored packed in cosmoline. My server logs show that a lot of people who find this page through Google were searching for something like

Some people try soaking parts in various combinations of lubricants in seach of the green shade. Usually it involves cosmoline, but also different cutting oils, axle grease, and so on. See this ODCMP forum page for some discussion of this.

On To The Project

Norinco corporation applies a nearly black and sometimes uneven bluing to their products, like this M1911A1 slide. The finish was unevenly blued and nearly black, and it seemed to be optimized for the collection and display of fingerprints. Having seen some nice parkerized finishes, my goal was to remove the bluing and parkerize it.

The first picture shows the frame in its original finish — nearly black.

Another page shows how to remove bluing with vinegar, click here to see that process.

Norinco M1911A1 pistol frame, in original blued finish.

Norinco M1911A1 pistol frame, in original blued finish.

Norinco M1911A1 pistol frame and slide, original blued finish has been removed.

The original blued finish has been removed in preparation for parkerizing.

Here are the slide and the frame after the end of the debluing process. The parts were rubbed with extra-fine steel wool and lightly oiled.

Time to move on to the parkerizing!

There was a delay between the removal of the bluing and the parkerizing — the parts were lightly oiled for storage between these steps. But as described below, all oil must be removed before parkerizing.

All oils must be removed before the parts are dipped in the parkerizing solution. Brake cleaner can do the job. Here begins the section that must be done "in a well-ventilated space".

Brake cleaner is basically an aerosol spray of hydrocarbon solvents. Acetone, methyl-ethyl-ketone, and so on. This can says "non-chlorinated", but chlorination is about the only organic chemistry not contained in this spray can.

Be careful to always use non-chlorinated parts cleaner spray! Chlorinated sprays can produce deadly poison gas.

Do not eat.

Do not apply directly to forehead.

Do not use while smoking a hookah.

Spray the parts down, and then handle them only in ways that will not transfer any skin oil to the metal.

You could do this in some more complicated way. Clean cotton gloves over rubber gloves, and so on.

However, we found that we could just handle the parts using paper towels that had been sprayed with brake cleaner.

Spray can of brake cleaner, used to prepare parts for parkerizing.

Brake cleaner: Cheap and effective!

The parts must be carefully bead-blasted. The guy who bead-blasted this did a very nice job.

Thoroughly clean the parts with brake cleaner after the bead blasting. Some skin oil probably got transferred to the parts, and brake cleaner is cheap and easy to use.

That is an old 100% cotton towel. I would be very careful to only use 100% cotton towels. Spraying the organic solvents of brake cleaner onto synthetic fibers might result in a real mess!

Bead blasted pistol frame and slide, ready for parkerizing.

Bead blasted pistol frame and slide, ready for parkerizing.

Close-up view of bead blasted pistol frame, ready for parkerizing.

Close-up view of bead blasted surface.

The result is a very light colored surface, nearly colorless. The de-blued steel was grey, probably due to some surface oxidation. I would describe the bead-blasted color as silver. The bead blasting has also given it a matte rather than a polished finish. The matte surface finish is probably the reason for the perceived color transition from grey to silver.

It is a dull matte grey, as opposed to a shiny silver mirror finish, because the bead blasting has made the surface irregular on a microscopic scale. The tiny pits capture oil, and their dense spacing along with the oil's surface tension means that the entire surface should be protected by a very thin film of oil.

We used Brownells parkerizing solution.

It's a mixture of phosphoric acid (H3PO4) and nitric acid (HNO3), with manganese salts in solution.

Phosphoric acid molecule.

Phosphoric acid, H3PO4

Nitric acid molecule.

Nitric acid, HNO3

Large jug of Brownell's manganese parkerizing solution.

Brownell's manganese parkerizing solution.

A gel containing phosphoric acid is what is called naval jelly, a thick gel that can be applied to surfaces to remove rust. Phosphoric acid is also a component of soft drinks leading to lowered bone density. It is also used in dentistry and orthodontics as an etching solution to clean and roughen enamel surfaces of teeth. I am not making this up.

Nitric acid was first synthesized around 800 CE by the Arab (or maybe Persian) chemist Jabir ibn Hayyari. Not that you really need to know this to parkerize steel, it's just a shout-out to the Arab and Persian scientists who gave us so much of chemistry (alcohol is an Arabic word), mathematics (algebra is also Arabic, while algorithm is based on a Persian name), early cryptanalysis, and so on.

The Brownells solution is used after being diluted with water in a 1:8 acid:water ratio.

Remember your chemistry lab safety, start with the water:
Do as you oughta,
Add acid to water.

USSR postage stamp of Muhammed al-Khwarizmi from, GNU Free Documentation License.

Muhammed al-Khwarizmi, whose name is the origin of the word algorithm.

Extremely important:
Use a stainless steel pot for the process! Or a cast-iron pot that will become parkerized on the inside the first time it's used.

Heat the parkerizing solution. We're doing this on a camp stove in a garage.

Also important:
A reasonably well-ventilated work area. You are about to heat an acid solution to near the boiling point, and this produces some nasty vapors.

Since the brake cleaner also needs ventilation, you're probably doing this in the same area you where you were cleaning the parts. However, do not have your brake cleaner anywhere near your open flame!

Heating the parkerizing solution on a camp stove.

Carefully heating the parkerizing solution on a camp stove.

We aimed for a temperature of 170-180°F / 77-82°C, at least in the sequence shown on this page.

Different temperatures produce different surface finish colors. The finish also varies with the mixture of acids and metal salts.

Measuring the temperature of the parkerizing solution: 170-180°F / 77-82°C.

We heated the parkerizing solution to 170-180°F or 77-82°C.

The acid/manganese solution is a fairly colorless and clear solution, it looks like slightly greenish water.

It starts fizzing as soon as you immerse steel. Very fine bubbles come off all the steel surfaces. The solution turns a more distinct green color.

You also get some flakes in suspension in the fluid. It looks like tiny scraps of paper, as if you had accidentally dropped some tissue paper into the solution.

We strung stainless steel wire through as many parts as possible so we could more easily remove them when the fizzing, reflecting the electrochemical reaction, stopped.

Hot acid and manganese solution used for parkerizing.

Parts disappear into the parkerizing solution.

Gun parts being parkerized in a boiling acid and manganese solution.

Vigorously fizzing parkerizing solution.

Larger parts like the slide and frame led to more vigorous fizzing.

All parts were finished after about 6 to 7 minutes at 170-180°F / 77-82°C.

Here is a video recorded during a different session. We lowered the small parts into the solution using a stainless steel ladle with three 1/8" holes drilled near its center.

The solution started fizzing almost as soon as the parts are submerged, you can clearly see this in the video.

The parts were fished out of the parkering solution and submerged in warm water.

For parts without through holes, we just threw them into the pot and fished them out with stainless steel hemostats.

American Science and Surplus is a good source of lab gear, including stainless steel hemostats and Pyrex beakers.

Water bath to rinse off the parkerizing solution.

A cool water bath stops the parkerizing reaction.

WD-40 spray lubricant to remove water and parkerizing solution.

Spraying the newly parkerized parts with WD-40.

After the parts had cooled and been vigorously sloshed around in the water, they were removed, dried, and dropped into a plastic pan to be sprayed with WD-40 spray lubricant.

Some people claim that the WD-40 stops the parkerizing process. However, it sure seems to me that the parkerizing is done by the hot acid bath in the presence of metal salts. Removing the part from the hot acid and metal salt bath and flushing it with water has far more to do with ending that chemical process than any spray of WD-40.

The WD-40 spray is good, but it surely serves mainly to remove the water and any remaining acid. Make sure to thoroughly spray the parts with WD-40, fully coating and thus flushing the water away from all surfaces.

Do not be frightened by the bandaged thumb!

That had nothing to do with the parkerizing project!

The important final step is to rub gun grease into the parkerized surfaces.

The parkerized surface is rough and effectively porous on a very fine scale.

These pictures show the frame after it has been reassembled. Of course, the lubricant must be rubbed into all surfaces before starting the reassembly. This is necessary to protect all of the surfaces, including the internal ones.

The external surface now has a microcrystalline structure which can be impregnated with oil, This oil not only protects the surface from wetting and undesired oxidation, but it also provides lubrication.

Refer to the field-stripping guide in reverse to reassemble it.

Parkerized M1911 pistol parts ready for lubrication and reassembly.  Red 'all weather high-tech' grease and a small bottle of 'Rem Oil' containing teflon.

Lubricating the parkerized M1911 before reassembling it, using red "all weather high-tech" grease and a small bottle of Remington's teflon-containing "Rem Oil".

Close view of the frame of a parkerized M1911 pistol, ready for lubrication and reassembly.

Close view of newly parkerized surfaces.

Frame and slide of a parkerized M1911 pistol.

Preparing to reassemble the parkerized M1911.

Reassembled parkerized M1911 pistol.

Reassembly complete! View of the left side ...

Reassembled parkerized M1911 pistol.

... and the right side.

Now, what if you're parkerizing something and you want to avoid parkerizing some part of it? For example, an M1 Garand barrel and you don't want to parkerize the bore, chamber, and gas cylinder mounting surfaces?

Just keep the solution away from those surfaces. For the example of the M1 Garand barrel, use appropriately sized rubber stoppers in the muzzle and chamber, and electrical tape over any external surfaces to be protected.

We wondered — what would happen if you tried to parkerize the spring steel clips used in the M1 Garand?

These pictures show that it can be done, and the result looks pretty good.

In the first picture, the left-most clip has been parkerized while the other two have not. The second picture shows a closer view of the parkerized clip.

It's not clear how concerned you need to be about oxidation of these clips, but they certainly can be parkerized!

Parkerized and non-parkerized M1 Garand en-bloc clips.
Parkerized and non-parkerized M1 Garand en-bloc clips.

WARNING: All content on this web site, including technical data, information, and reports of any activities, do not detail the comprehensive training, procedures, techniques, and safety precautions which are absolutely necessary to properly carry out similar activity. The reader MUST NOT attempt any reported activity, technique, or use of equipment based on reports on this web site. Always consult comprehensive reference manuals for details of proper training requirements, procedures, techniques and safety equipment and precautions before attempting any similar behavior.


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Join Date: June 23, 2004

Location: Ohio

Posts: 5,676

I don't like sand blasting on most parts as it leaves too rough of a finish for me. I do fine glass beads so that you get sort of just a matte satin finish on the steel, not a coarse one. When I got started the zinc solution I bought was supposed to be mixed at 12/1 dilution in rain water or distilled water. I got a bottle of Manganese at a gunshow that had no instructions. I tried the same mix and got fine results. But Brownells might recommend something else, I would do what they say. I have usually used some stuff called Mounts neutralizer that is an oily spray that really stinks after rinsing the parts post treatment. Works fine but something else might work as well, but the special stuff supposedly neutalizes the chemical reaction of the acid on the metal. I heat my solution to about 160-170 F. on a stove top(thermometer used) and that seems to work ok. No boiling water used here. Still funny things can happen with your results depending on the heat treatment etc. of the gun steel. Had a slide with a slightly darker finish on one end due to the fact the Red Chinese apparently did not harden the slides full length the same? And a carbine bolt that came out an odd gold color once. But nearly always looks works perfectly for me. No need to remove the blueing, the steel should be 100% bare when you bead blast. But degreasing is important too.

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The Following is a Basic Do-it-yourself Manganese Parkerizing Formula

A couple of friends online, Elkaholic and Ding, got me interested in parkerizing years ago and gave me a home brew formula and process steps they use.  I have been tuning that formula for a few years and thought I would share it as I use it both for blades and firearms.  It works great as either the base for a top finish, such as Molyresin or as a finish all by itself.  You may be wondering “why not just buy a premade formula such as the great parkerizing solution from Brownell’s” – the short answer is because tinkering can be fun and more rewarding.  I like to experiment and try different things.   So, with that said, here is the recipe:


– 2 gallons of distilled water  (it gives more consistent results because impurities have been removed)
– 2 “biscuits” of clean 0000 steel wool (thinner steel wool dissolves faster hence the use of 0000 grade)
– 1 cup of Klean Strip brand Phosphoric Prep & Etch (or other phosphoric acid etching solution around 35-45% concentrate per the Prep & Etch MSDS sheet)
– 6 rounded tablespoons of manganese dioxide (available at pottery supply stores, Amazon or eBay)


Do this outside – never in your house or shop (unless you have a great vent hood).  If you do it indoors, you will likely make stuff rust fast!


As you can see, I use a camp stove.  For the first couple of years I just used a Coleman stove but that was always a balancing act with my 48″ long stainless pakerizing tank that I used for barreled actions.  I found the above great Camp Chef stove at Amazon and it is fantastic but any heat source will work.

Also, be sure to use stainless steel for your tanks.  I watch for sales or buy stuff off eBay.  The big cooker above is from Walmart and the rectangular pan shown below is from Amazon and is normally the water pan for buffet lines.

For tongs to move stuff around, use solid stainless.  I tried the plastic ones and they can leave a plastic residue on blasted surfaces and mess up your finish.

Just like baking, if you want more of the solution, take the recipe and multiply it by two, four or however many multiples you want. Just be sure you have a place to store it when done.  I use 5 gallon jugs and label them.

Steps to Follow

  1. Add acid to water in a stainless pan/pot and heat to 190F – don’t boil and waste it.  I use a baking thermometer clipped to the side of the pan.
  2. Spray each wool biscuit with brake cleaner to remove oils and allow each time to dry
  3. As the solution warms shred the steel wool into the liquid and add the manganese dioxide
  4. Let the mix simmer and dissolve the steel wool before adding parts
  5. I always blast my parts before I parkerize them – I’ve heard guys tell about using a wire brush on a buffer or drill press as well but I’ve not tried that.  Blasting removes the oxides and exposes the bare steel.
  6. Make sure your parts are very, very clean and degreased — only handle with rubber gloves after they are cleaned or oils from your skin can mess things up
  7. You can suspend your parts in the liquid with stainless wire.  Leave them until the fizzing stops or about 30-40 minutes.  The time varies.
  8. Rinse the parts with boiling water thoroughly to remove the acid.
  9. Spray parts with WD40 to get the water away from the steel
  10. Wipe down with oil or apply whatever secondary finish you want – don’t do both 🙂  If you are going to apply a finish on top of the parkerized surface, use acetone or brake cleaner to remove any oils and then follow their instructions.

At the bottom of the post are links to Amazon products including long parkerizing tanks.

Cleaning Up

When you are done, let your mixture cool and strain the liquid through a coffee filter into a plastic can for future use. I use a blue kerosene 5 gallon container because it is a different color from all my other 5 gallon containers plus I label it.  Point being, you do not want to get confused and pour this stuff in when you meant to use a fuel, etc.

The precipitate, the stuff on the bottom, should be scooped onto a shallow pan, allowed to dry and be disposed of as a hazardous waste.  For example, where ever your community collects old paints, batteries, etc.

Brownells Has Great Parkerizing Solutions and Kits

Brownells sells very well regarded ready-to-use formulations. I have no hesitation at all to recommend the below items to you – they are top notch.

  • Click here for their manganese parkerization supplies. Their formula meets Mil Spec STD171
  • Click here for their zinc parkerization supplies
  • If you have a lot small parts you want to park, they have a bench top kit ready to go that you can buy – click here
  • Click here for their complete parkerizing tank system. This is a complete system for gunsmiths or others who need to park everything from small parts and pistols up to firearms and swords.

In Summary

I hope this helps you out. I’ve used the above many times and the results are solid. Also, the following are many of the items you will need and are easy to order right off Amazon:

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at [email protected]. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

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I set up a small Parkerizing station using Brownells chemicals. Followed their instruction to the letter with good results. However, I would like to see a darker (more black, less gray) color. I tried different surface prep variants (AO & glass bead) and adjusted (longer) dip times. No luck. Any ideas?

The first batch of new chemicals usually come out light gray for me.  I think the solution needs to be seasoned.  I also degrease a small piece of steel wool and drop it in the new solution.  I bring the heat up slowly and let the chemicals/heat do its thing to the steel wool.  I then let the solution cool all the way down and park several hours later or the next day when the solution is cold.

I get very good results when I AO blast the parts and degrease.  I set the temp on the burners pretty low and place the parts in.  If I drop the parts in the tank as the solution is getting up to temp (170-185 degrees), the dwell time for the parts to darken actually decrease.  If the solution gets over 190, the parts do not react with the chemicals anymore.  That's why I keep the temps lower so the acid solution has more time to adhere.  Depending on how many parts I have, I get several runs of parts before the park lightens up.

BTW, I use Maganese Phosphate instead of Zinc, phosphate....

Parkerizing instructions brownells

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