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....
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....
This page is about chemical treatment of steel, but the example shows weaponry. If this would bother you, then you probably should not look at this page. Maybe you should instead look at a page with funny pictures of kittens. Although, as seen in the example at right, even that may disturb some people.
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:
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 took the pictures.
OK, enough lawyer repellent...
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 protects from corrosion and increases wear resistance.
There are several related techniques, but generally they involve a phosphoric acid 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. 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 |
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
green parkerizing
Some people try various combinations of lubricants for soaking. Usually it involves cosmoline, but also different cutting oils, axle grease, and so on. See this ODCMP forum page for some discussion of this.
I have a Norinco M1911A1 that had been blued. This being produced by Norinco, it was unevenly blued and nearly black. Having seen some nice parkerized finishes, I decided to try to remove the bluing and parkerize it.
Here is the frame in its original finish — nearly black.
I have another page on how I removed the bluing with vinegar, click here to see that process.
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!
All oils must be removed and kept off until 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".
It's 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.
Do not eat.
Do not apply directly to forehead.
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 just could use paper towels that had been sprayed with brake cleaner.
The parts must be carefully bead-blasted. The guy who did this did a very nice job.
Further shots of brake cleaner afer the bead blasting will be a good idea, in case any skin oil got transferred to the parts.
The result is a very shiny, very light colored surface. Nearly colorless. The bead blasting has also given it a matte rather than a polished finish.
Here is the basis of the parkerizing solution.
It's a mixture of phosphoric acid (H3PO4) and nitric acid (HNO3), with manganese salts in solution.
Here are phosphoric and nitric acid:
Note that a gel containing phosphoric acid is what is called naval jelly, a thick gel that can be applied to surfaces to remove rust. It 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, see the Wikipedia article.
Furthermore, note that nitric acid was first synthesized around 800 CE by the Arabic (or maybe Persian) chemist Jabir ibn Hayyari.
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.
Extremely important:
Use a stainless steel pot for the process!
Heat the parkerizing solution. This is being done 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.
We aimed for a temperature of 170-180°F / 77-82°C.
Not as hot as described on the Wikipedia page.
Different temperatures produce different resulting surface finish colors.
The finish also varies with the mixture of acids and metal salts.
The acid/manganese solution is a fairly colorless and clear solution, it looks like slightly greenish water.
As soon as you immerse steel, which is some iron/oxide compound, the material starts to fizz. The solution turns a more distinct green color.
You also get some paper-like flakes in suspension in the fluid.
We strung stainless steel wire through as many parts as possible to more easily remove them when the fizzing, reflecting the electrochemical reaction, stopped.
Larger parts (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.
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.
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.
There is some 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 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 it down with WD-40, fully coating and thus flushing the water away from all surfaces.
Don't 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 porous on a very very fine scale.
This is due partly to the bead blasting, and partly to the parkerizing itself.
The external surface has a microcrystalline structure which can be impregnated with oil, This oil not only protects the surface from wetting and undesired oxidation, but it provides lubrication.
Reassembly time — refer to http://www.m1911.org/stripin1.htm, reading it in reverse.
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