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Page AR-15 » Build It Yourself
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Posted: 7/2/2002 9:15:42 PM EDT
I`ve been messing with this for a while now and I think I`ve stumbled onto something that will give good results.
Parkerizing is a manganese phosphate coating,you can either buy the chemicals from Brownells or if you`re like me mix them yourself,I had been planing on buying some powdered manganese dioxide from a pottery supply house,but when I got ready to place the order I was struck by an idea.......zinc phosphate can also be used to parkerize....where can one get zinc?......look between your couch cushions....see those pennies? not copper anymore.Theyre copper plated zinc!I`m not sure when the mints quit making all copper pennies but I know anything since at least 1990 is copper plated zinc.I sanded the copper off 4 pennies till I had disks of zinc,heated up 8 oz. of phosphoric acid in a measuring cup in the microwave(phosphoric acid can be bought at home depot,it`s sold as a primer for bare metal it`s usually called ospho or ph-ospho-ric a green liquid,about $8 a gallon)then I dropped the zinc disks into the hot liquid,they fizzed like alka-seltzer for about 5 minutes then I pulled the zinc out.I added another 24 oz. of tap water,poured the mixture into a pyrex baking pan and heated it in the microwave until it was just starting to boil.I placed a clean grease free sandblasted knife blade into the liquid and waited 10 minutes,it came out a beautiful dark matte black.I washed it off in scalding water let it dry then immediately oiled it.This is just the experimental stage of this proccess,I`ll be trying different amounts of acid/water and zinc/acid and the ratio may yield different results if altered,I`ll be trying that.Anyway I just wanted to share the result of my tinkering with you,I`m quite pleased.
Bossman
Link Posted: 8/27/2002 11:04:25 AM EDT
[#1]
Well, I just got through parkerizing a knife blade as a trial.Did my old timer sharpfinger. I'm pretty pleased with the result but I wish I would have taken the time to prepare the blade a little better. It had some dark spots on it and they still show through the parkerize. But, the "clean" metal parts of the blade turned out real good. I only mixed up a small amount. Here is the recipe I used:In a 16oz. Pyrex measuring cup 12oz. tap water,bought to boil on side burner of my gas grill.Added 2 oz. of Prep-N-Prime(phosphoric acid) and about 1tsp. of Manganese Dioxide that I took out of one of those square 6volt lantern batteries. Stirred it up with a stainless steel spoon,and put knife blade in the still boiling solution for 20 minutes.Took it out and rinsed it of in hot water and oiled it. I don't think it ate away any metal because the edge will still shave the hair on my arm. I think I'll use this recipe on my 1911 slide after I sandblast it.-Gump
Link Posted: 8/27/2002 7:34:28 PM EDT
[#2]
Guys,dropdbomb is absolutely right in the fact that this process will change the parts dimensionally.That nice fighting knife blade I had pictured on page 1.....I had meticulously drilled and tapped the handle tang for 8-32 button head cap screws,it looked really nifty,I took great pains to shorten them so the would meet perfectly in the middle,I decided to parkerize the screws to match the blade and they came out looking wonderful,I went to torque then into the handle and they stripped with the slightest pressure-I said bad words-the holes got bigger in the park and the screws got smaller.SHEESH!.I think all parkerization processes will do this to some extent,do yourself a favor and mask off the slide rails or anywhere else there is a fit or tolerance issue,I would use several coats of clear nail polish then after the park bath remove the polish with acetone and a small brush.
Bossman
Link Posted: 8/29/2002 5:34:08 AM EDT
[#3]
I like the idea of this home parking but I just was wondering about the prep work. I have a bunch of sten mags I would like to do. I guess the first step is to remove the bottom plate, remove the spring and follower. Then do a preliminary cleaning in some kind of solvent to get heavy grease off but what should I do next?
should I boil them in something like Trisodium Phosphate or (hope the wife don't see this) run them through the dish washer? finally, do I need to sand blast the mags or will the phosphoric acid texture the surface during the parkerizing?
Link Posted: 8/29/2002 8:15:06 AM EDT
[#4]
Pops,I`m not sure if the sandblasting is neccessary or not but it sure is worth the effort as fas as looks go.
What I do with my knife blades is when I`m ready to park them I sand blast the heck out of them,then blast away any leftover sand/oil/dirt with a can of brake parts cleaner.Get it good and clean,and handle it with tongs or something from that point on,fingerprints will blotch the finish.When the blade comes out of the park bath,dip it in boiling water with a bit of baking soda mixed in to neutralize the acid,wash it off with scalding water and just as soon as it`s dry oil it down real well.
Bossman
Link Posted: 8/29/2002 9:22:32 AM EDT
[#5]
Sten mags have a lot of little hiding places built into them and that's why I was wondered about the trisodium boiling. Also, in blasting your knife blades do you use sand or beads?
Link Posted: 8/29/2002 12:00:23 PM EDT
[#6]
Pops,I just use plain old "play sand" from the hardware store.
Link Posted: 8/29/2002 5:22:54 PM EDT
[#7]
Nice knife Bossman !!!  Have you tried using Alder for any of your handles (alder is extremely resitant to water; used a lot in the NW for pilings in the sloughs and mill ponds).

Have you tried adding some sort of "dye" to your mixture in hopes it changes the colour somewhat ? Also, I've found in the "traditional" parkerizing that quenching the part in cozmoline right after the bath gives it the "OD" sort of look (depending on the age, shade, and cleanliness of the cozmiline).

How is it you harden your blades ? I've been tryin' to fig'r a way to do it now that I've ran out of transformer oil (from the old PP&L pots they mount on the power poles; lots of carbon in them).

"...freedom without sacrifice is NOT Liberty."

'bonz
Link Posted: 8/29/2002 8:29:09 PM EDT
[#8]
Thanx,krosbonz
I did a little tutorial some time back that includes my heat-treat method,since that post I`ve gone to using straight vegetable oil,pre-heated to 120-130 degrees.
assaultweb.net/ubb/Archives/Archive-000009/HTML/20010716-13-000093.html
the pix quit working and I really dont have time to fix them but the text is still valid.
The whole series is here:
assaultweb.net/cgi-bin/forumdisplay.cgi
Here`s my latest creation,I do a bit of selling and trading for gun parts at the assault web.net board,I think I might have to offer some of my toys here,as I`m in need of some AR-15 goodies possibly in trade for some custom knives.




I`ll be putting this blade up for sale tomorrow night on the AW.net "for sale" forum,
assaultweb.net/ubb/Forum12/HTML/207640.html
I usually offer small neck knives at that forum,between $35 and $65 depending on size and details,they sell like hotcakes,Hmmm, maybe I should do a set here on this board and see what happens.........
Thanks for the kind words,
Scott Fulford(Bossman)pages.prodigy.net/sjfulford
Link Posted: 8/29/2002 11:30:01 PM EDT
[#9]
Great thread Bossman !!!
Couple of questions:
~instead of using a file.....could some good steel like leaf springs, etc. be used once they are annealed???
~is the rest of the "tutorial" available ???
~once the blade is "hardened" again and baked, will the parkerizing adversely affect it in any way ???
Thanx again.....
"...freedom without sacrifice is NOT Liberty."
'bonz
Link Posted: 9/10/2002 5:24:55 AM EDT
[#10]
Well I went and tried parking a mag that I had just modified. It's the first time I've done this and was worried that I was going to mess up a good mag but it came out ok. I used the zinc in the pennies procedure on the first mag because the pennies are easy to find.

As soon as I figured it was finished (about 25 minutes) I took the mag out of the parking broth and dunked it right into a bucket of used engine oil. The chemicals and the oil must react with each other because it kind of frothed slightly. A second mag was tried in a new batch with the black manganese powder from some alkaline batteries but I guess I screwed that up and it came out a blotchy mess but the etching was real nice so I cleaned it and sprayed it with Brownell's black Aluma Hyde II.
I guess I'll get to find out which is more durable. I also see why Bossman said he liked to sandblast before parking -- these are sten mags and they are rough and it still shows after parking. I'll need to try that on my next set of mags.
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