black oxide after parkerizing?


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m0par
December 2, 2009, 11:30 AM
Newbie here (as will soon be apparent).

I knew it was a gamble, but was willing to take it, and lost...

I did some metal work to a 1911 frame which then required re-parkerizing. I knew I would be better off blasting and parkerizing the slide at the same time if I wanted them to match.

Well, now the frame is just a shade lighter than the slide,:banghead: so I was wondering, can a manganese-parkerized part be black-oxide dipped?

I would just blast it again along with the slide and reparkerize the whole shebang, but the serial number on the frame is so lightly stamped that I fear I would risk being accused of obliterating the serial number, even with glass beads.

So instead, I was hoping to try a black-oxide process, in hopes that the solution would penetrate the parkerizing and possiby darken the base metal, allowing for a color match. (the slide is nearly black, and the frame is now a fairly dark charcoal-gray)

The problem is, I am not a chemist/metallurgist, and for all I know, the black oxide dip (caswell plating's product) may completely dissolve the parkerizing.

Any suggestions?

Thanks.

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highorder
December 2, 2009, 11:34 AM
I don't think you'll have any luck with a black oxide dip over the parkerizing.

If you want to blast again, just restamp the serial number. No biggie, regardless of what the internet will tell you. I personally would glass bead everything and repark both pieces together if I had to have an exact color match.

justashooter in pa
December 2, 2009, 12:39 PM
if i were you i would try greasing the gun, first. a manganese park will appear to be different in shade depending upon what kind of oil/grease you apply to it, as well as what kind of alloy the steel is (low carbon = black, alloy steels turning green). personally, i prefer pennzoil axel grease.

field strip the entire gun and wipe it down with grease liberally (not the wood grips), putting the parts into a ziploc baggie. sit this in a warm place (in the summertime in the sunshine, in the winter over a heat register) and let sit for a day. remove parts from the bag and wipe down with paper towels till the towels come out clean. reassemble. do not clean with solvents (parkerised finish was designed to be greased and left that way).

if this doesn't fix it, clean the frame with braakleen to degrease and cook it in the park some more. it will darken, as long as the parts continue to fizz. your temperature should be about 190*F, with higher temps for higher alloys. you might need to get up to 200* to get the fizz. differences in the alloys used in making your gun may be contributing to the difference in color, so you may never get a perfect match.

as for re-marking serial, i agree you should avoid if at all possible. makes no difference what the rules really are. a street cop may hose you for any marking that appears to be altered, and let your lawyer sort it out. you don't wanna go there.

a tip on blasting: use aluminum tape that you can get in the heating supplies section of lowes to tape up any areas you don't want to alter in sandblasting (polished surfaces, inside of frame, etc.)

highorder
December 2, 2009, 01:40 PM
as for re-marking serial, i agree you should avoid if at all possible. makes no difference what the rules really are. a street cop may hose you for any marking that appears to be altered, and let your lawyer sort it out. you don't wanna go there.


With all due respect, this is the sort of internet fear mongering I was talking about.

Can anyone cite any situation where anyone has had any problem with moving or simply deepening the legitimate serial number on a legally owned firearm?

No?

A quick trip around google shows that it gets done all the time, for the same reasons you have.

The rest of the information is spot on.
It sounds like you've spent a good bit of time with parts bubbling in the parkerizing solution. :)

gb6491
December 2, 2009, 07:23 PM
I've used Brownells Oxpho Blue post parkerizing to darken small parts with very good results. I submerge the part and let it sit for a while and remove when I have the results I want.

Here's a tutorial where the author states he uses the Caswell Black Oxide as a post parkerizing solution:
http://www.projectguns.com/parkerizing.html

Regards,
Greg

Jim Watson
December 2, 2009, 08:09 PM
Bluing a Parkerized part gives a dead black finish.

highorder
December 2, 2009, 10:37 PM
I stand corrected on bluing parked parts.

I'm standing my ground on restamping serial numbers. :)

m0par
December 2, 2009, 10:39 PM
Well, thanks for all the info. Gonna give the black oxide a try this weekend. Wish me luck...

I don't think degreasing and re-parkerizing will help in my case. When I first did it, the fizzing had stopped long before I took it out, and I let it approach Brownell's recommended 15-minute time limit in hopes of a darker finish.

Which brings to mind another issue. I used an electric hot plate, stainless pot, and maintained a temp of 185 according to the thermometer. If I tried to go any higher, the solution would react quite strangely and somewhat violently. It was like I created a mini geyser. The pan would make a loud bang, and the solution would shoot up out of the pot. It seemed like it was creating a large gas bubble instantaneously at the bottom. I was afraid to get too close to examine what was going on :) Anyone experience anything similar? Maybe my thermometer is reading low.

relocker
December 3, 2009, 08:48 AM
Are you sure it is the solution reacting? I've used cheap stainless pots before with thin bottoms and they seem to temporarily warp when they reach a certain temperature, usually with the sudden "bang" you describe, then do it again as it cools. It's like the bottom suddenly goes from concave to convex. This would explain the splash as well, with only a couple inches of fluid in the pot.

Try heating the pot with water and see if you get the same "reaction".

m0par
December 3, 2009, 09:22 AM
Nope, I'm not sure. All I know is it scared the bejesus out of me the first time. I've cooked with this pot for several years and it is not a thin one. Its a knock-off of an allclad (tri-ply stainless-aluminum-stainless across the base and all the way up the sides). Never acted that way before, but I've never tried keeping it at 180+/-. I'll have to try it with plain water some time.

justashooter in pa
December 3, 2009, 10:53 PM
two problems: your kitchen thermometer is off a bit, and you were approaching boiling point at the interface. the temperature of the pot is not the same as the temperature of the water. put the tip of the probe on the bottom of the pan and you'll see for sure. i have some cheap hardware cloth (wire screen) stretched over one end of the 48"X6"X6" stainless tanks i use and poke the probe thru it till the point is about an inch off the bottom. i use a gas 2 burner, but really should be using a tube burner under the full length of the pans.

i have trashed several thermos in the 20 or so guns i have parked. they are just chinese crap that aren't worth the 3 bux you pay for them.

manganese phosphate solution is not anywhere near as nasty as the acids you use in bluing, but a third degree burn will still spoil your day.

did you note a significant reduction in water level during the 15 minute soaking period? if so, your solution has thickened and you need to add more distilled water to get it to behave more predictably. i have found that the best park jobs come from soultion that has been aged 5 or so guns, but kept free of grease by careful cleaning of parts before entering the solution.

the best set-up will have 4 tanks in a series, with a TSP solution boil to do a final removal of oil from parts and preheat them, a parkerising tank, and a neutralising tank of clean water at boiling temp, followed by an immersion tank of WD 40. parts are not put into the WD until they appear to be dry, which won't be long if the boil is hot. of course, stainless steel .015 wire, stainless baskets, or even a stainless steel kitchen french fry basket can be used to handle parts without contaminating them or burning fingers.

another tip: don't let your parts lie on the bottom of pan. suspend them in the solution just above the bottom of pan with SS wire, or you will get areas of uneven color. this is a result of the difference in temp between the bottom of pan (and parts in direct contact) and the solution, and the reduction of chemical reaction caused by the inhibition of solution movement and gassing.

did i mention that i parked a 12 gauge ithaca 37 last week? i had bought it cut to 22 and in a nasty mottled rust but with good wood for 85 bux. i cut it to a proper 20" and installed a new brass bead before blasting and parking and oiling the walnut proper. i made the mistake of putting it in the rack in the dining room the day before my oldest son came home for thanksgiving. he didn't say much before taking it down and throwing it in his bag, other than, "gee dad, this is a really neat copy of the VN era riot gun configuration. did you know we lend leased about 40 thou of these to ARVN? my friends are gonna think this is really neat..."

jaysouth
December 4, 2009, 07:12 AM
Is it a parkerized finish you are after? If not, a park base with dura kote top coat is a very durable finish.

By the way, the ATF folks with whom I am acquainted do not think it is OK to move a SN. I have a BHP from a very well know custom shop. The SN was engraved above the right grip panel so they could stipple the front grip. The ATF Technical rep I spoke with said that I was not in trouble since I did not actually move the number, but it was not legal for the smith to do that. Yes, they had seen hundreds of BHPs with similar treatment.

This conversation arose from my asking "what form do I use to report moving a SN". I was under the mistaken impression that this practice was common and legal. Common, yes, but legal, no.

Restriking or deepening SNs? As long as it's the same number, you should be OK.

highorder
December 4, 2009, 10:43 AM
By the way, the ATF folks with whom I am acquainted do not think it is OK to move a SN. I have a BHP from a very well know custom shop. The SN was engraved above the right grip panel so they could stipple the front grip. The ATF Technical rep I spoke with said that I was not in trouble since I did not actually move the number, but it was not legal for the smith to do that. Yes, they had seen hundreds of BHPs with similar treatment.

This conversation arose from my asking "what form do I use to report moving a SN". I was under the mistaken impression that this practice was common and legal. Common, yes, but legal, no.

Now we're getting somewhere.

This is an interesting situation. By the letter of the law (27 CFR Ch. II, 479.102 (http://frwebgate1.access.gpo.gov/cgi-bin/PDFgate.cgi?WAISdocID=938197172199+20+2+0&WAISaction=retrieve)) only the manufacturer of a firearm may apply (or reapply) the serial number to a firearm. In the same breath, some people doing HK SL8/G36 conversions were told by ATF (see attached letter (http://www.thehighroad.org/attachment.php?attachmentid=110347&d=1259940294)) that moving the serial number was forbidden. The sticking point is, they were creating Title II firearms, effectively becoming the "manufacturer" of said firearm. They contend that this gives them alone the authority and responsibility to apply a serial number.

There are at least 3 court cases touching on this point, with contradictory opinions. In addition to that, here is an older opinion from FRANK J. KELLEY, MICHIGAN ATTORNEY GENERAL (http://www.ag.state.mi.us/opinion/datafiles/1970s/op05215.htm) that says that the Michigan State Police are authorized to restamp a serial number that has been intentionally defaced, and the owner of said firearm is immune from (state) prosecution. This is in direct conflict with federal law, but I don't believe it would have any bearing on prosecution by BATFE.

I'm just glad the answer is clear... :rolleyes:

What I now know is that according to BATFE, even deepening an existing serial number would constitute "alteration."

All I find on the web are opinions and situations regarding additional crimes that also involved a firearm.
I haven't found any prosecutions based solely on the moving or "deepening" a legitimate serial number, although it is clearly forbidden based upon the last paragraph of the BATFE opinion letter.

Riss
December 9, 2009, 03:31 PM
Don't the States have rights that violate even Federal Law ? YES they do. Anyway. It have gotten the best Parkerizing jobs from putting the parts into a cold bath and slowly bringing the whole mess up to temp SLOWLY. I blast the parts and RINSE only. No soap, no cleaners, just good water and then straight into the cold Park bath.

m0par
December 14, 2009, 12:24 AM
It have gotten the best Parkerizing jobs from putting the parts into a cold bath and slowly bringing the whole mess up to temp SLOWLY. I blast the parts and RINSE only. No soap, no cleaners, just good water and then straight into the cold Park bath.

I'll have to try that on the grip safety. I don't know what kind of metal they used to make it, but it sure didn't take the parkerizing like the rest. It was prepped and processed exactly the same as the other parts and at the same time, but was very slow to start reacting, and ended up splotchy and rough--almost chunky looking. Gonna redo it.

FWIW, the oxide dip after parkerizing the frame worked quite well. It is still the tiniest bit lighter than the slide, but much better. I can only detect it in sunlight. Its not a show piece so I'm quite content with it. Maybe I'll try another dip the next time I have it stripped down.

Riss
December 14, 2009, 11:10 AM
You are best off the very slowly bring the temp up from cold. I sometimes set mine on simmer and walk away, come back minutes later and bump it up to 2, later 4, and 6, etc. It will take over an hour to bring it up to temp and sometimes I leave it cooking for over another hour. It depend on how reactive the part is and how many bubbles I get. Either way I would rather let the bath do the cooking of the part than sit there and watch it for over an hour. I will have to try the black oxide as a post treatment. Are you using the Caswell oxide, or something from Brownells ?

justashooter in pa
December 16, 2009, 10:13 PM
failure to clean with a boiling TSP will leave oil residue in your park if your parts are at all assembled, as when doing AK kits with sight block installed. going from hot water straight to park is dunlap's advise, and part of the original parker coating company dogma. always works great for me.

grip safety could be a high strenght alloy with considerable Cr and Ni.

Riss
December 16, 2009, 11:45 PM
Let me explain what I call a GOOD Parkerized job. I usually like dark black with good crystallization showing. I have gotten the light colored Park going in the past and is probably what Dunlap was talking about. In order to get a military type Park job that is. The military stuff was always lighter and the Cosmoline always seems turn turn it that nice green color.

justashooter in pa
December 18, 2009, 05:51 PM
color acheived in parkerising is dependent upon the actual chemistry of the bath and the steel treated in it. manganese phosphate, manganese dioxide with phosphoric acid (richard's formula), phosphoric acid with iron filings (coslett's formula) , modern formulas, you choose it. mild steels tend to come out dead black, tending toward gray. grey, green, or blue black as the nickle content increases. sandblasting makes for a blacker finish than glass bead blasting (trick of reflective light). so many variables.

black oxiding has been around since the early 1900's. sodium hydroxide mixed with potassium nitrate and sodium nitrite is a classic formula. sodium cyanide can be added, (witrh obvious risks, as it is highly poisonous). lowery's blackening solution is also worth mentioning: lye & amonium nitrate.

m0par
December 19, 2009, 10:02 AM
Are you using the Caswell oxide, or something from Brownells ?
I used Caswell's. It didn't turn it jet black (which in my case is good, since then it would have been darker than the slide), but did darken it enough to be a good match to the slide.

I had already lubed the frame after the original parkerizing, so there's a good chance I didn't get it completely oil-free between the parkerizing and black oxide (not for lack of trying). I can only imagine it would have been even darker had I went straight from parkerizing to the black oxide.

As an aside, does anyone know anything about Blue Wonder's Gun Black? Is it just a black oxide treatment like the Caswell's?

jjk308
December 20, 2009, 05:44 PM
It's perfectly legal to restamp the serial number in the same location and its standard for professional gun refinishers to do so if the number becomes illegible.

I believe the BATFE opinion is wrong because of the wording of the law, which refers to altering, removing or defacing but not moving the number, the purpose of the number being for identification, but its one of those things nobody in their right mind would spend the resources to contest it.

Riss
December 20, 2009, 07:10 PM
I believe the BATFE opinion is wrong because of the wording of the law, Well, the way it has been going lately, BATFE opinion IS THE LAW. You would have no luck fighting with them.

highorder
December 20, 2009, 07:47 PM
I believe the BATFE opinion is wrong

Ha! You, me, and everyone else out there. But,

BATFE opinion IS THE LAW

Right or wrong, BATF tech branch opinions carry weight. Act accordingly.

navyretired 1
December 25, 2009, 09:19 AM
Glass beading parts will not washout serial numbers. I must be confused because I thought black oxide is a parkerizing process. I aggree that placing freshly parked gun in heavy grease will darken color but won't match mismatched color. I personally like the light gray but because you get that nice greenish gray after grease treatment.
Serial numbers maybe added at different location to suppliment light stampings but maynot replace factory serial numbers. You cannot remove or deface original number EVER.
In the old days one popular job was round butting K-frame Smiths, well guess where the ser. number was. Have had a serous talking too by tecnical branch ATF about a very slick little mod 10 I round butted, put 2" barrel and Nitexed with Jordan type grips. The serial number is also inside crain so I thought I was good, They gave me a real ration of sh_t during inspection but I finally got a letter to cover my a_s because Smith put than number in crain.

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