There was a discussion in this thread, Picked up a JK era 226, about refinishing a SIG, stripping off anodization is "indefensible", compromised vs. non-compromised frame, etc... that I want to take to a new thread with a better title that reflects the discussion and with a little more expansion.

First, let me say that I am a non-expert on this refinishing topic. I'm only offering what I learned from rudimentary readings and from discussion with one expert (Joe Dudenhoeffer, the current president & CEO of Klein Plating). If anyone disagrees, feel free to offer your expertise.

1- Does Robar strip off the anodization from the frame, when prepping to plate it, either in EN or NP3?
Yes, they do. They have answered this question previously. It's no secret.

2- Did Klein strip off the anodization from the frame, when prepping to EN plate it?
This question I know has bugged many of us for the longest time. Some speculated yes, and some said no, but none of us knew the answer. So, I asked Mr. D, and straight from the horse's mouth the answer is yes, they did. He gave me permission to share with the forum his answer. Gracious man, taking time out from his busy schedule to quickly answer.

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In terms of the prep work for plating a Sig, both the bluing and anodizing were removed after the firearm was completely disassembled. These coatings are basically super imposed oxides that form a protective barrier for the basis metal. Removing all surface oxides is a vital step in the plating process, so you generally cannot plate over them (although there are a few proprietary processes for it). When KPW plated a Sig, the frame’s anodizing was stripped off through a chemical procedure then glass beaded for uniformity and further cleaning prior to entering the electroless nickel plating process.

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I won’t go into too much detail about our process since we may someday plate firearms again. However, that possibility is rather slim.

In my opinion, Klein has/had a few things that made our firearms standout a little. One was the craftsmanship that went into them. Back in those days, that department was ran by a man named Txx Txxxxxxx who happened to be one of my first bosses. Tommy was a perfectionist and that mentality is really what you need when finishing anything aesthetically . We ran a custom finishing division back then so we had the tools and expertise to refinish and work all kinds of metals. We refinished and plated church work, antiques, hardware and other things along with firearms. Knowing how to and putting the effort in to properly prep the metal is a huge part of the equation.

Another aspect that may set Klein apart is we are a high reliability plating shop. Many of the parts we plate go into aerospace, defense, power generation, etc. so all of our processes follow strict controls that are monitored and audited. Plating is a rather complex chemical process and needs a great deal of daily maintenance. Having strict process control usually leads to excellent final finishes so you are correct when you say nickel is a great finish when done properly.

3- So, is stripping off the anodization an "indefensible" practice?
According to Bruce, it is. Quoted from the other thread, where Keystoner received an email from Bruce, "stripping anodizing is indefensible in my opinion". I greatly respect Bruce, but I'm going to have to disagree just slightly. Here is why.

a- Plating is a complicated process involving many steps. There are bad refinishers out there, just as there are outstanding ones. You have to know what the hell you're doing. Prep work is critical, as Mr. D pointed out. Do a sloppy prep, and it's unlikely you'll have great result. Having a shop doesn't automatically qualify you as expert. Perfect example is the local guy that did the EN job on Keystoner's SIG. He ruined the frame.

b- On the other hand, outfits like Robar and Klein, which have been doing this for years (Klein has been in the business for over 100 years), must be doing it right. Otherwise, we would be hearing about all the failures from their anodization stripping. Forum member SIGagain had an originally blued P228 that he personally sent in to Klein in the 90s for Ni plating. He last reported that it's still going strong. He posts a nice pic of it on here once in a while.

So, the bottom line, imho, is that anodization stripping in the plating process is indefensible, if you're sloppy and don't know what the heck you're doing. But, in expert hands, you will be ok.

Notice that I didn't include CCR in this discussion because, although their CPII (another plating process) is outstanding, they do not plate alloy frames, because, like Bruce's opinion, they will not strip the anodization. Also, "spray-on" type finishes are excluded from the discussion, as they are not plating processes.

So the upshot of all this is that if you must have a SIG plated, only let the very best people anywhere near it. This has been a practice of mine for many years for anything. And that includes, in many cases, myself. It is, for example, why I shipped my CZ to CGW in Louisiana for trigger replacement and other work.

I've had at least 10 guns redone in NP3, mostly SIGs. My oldest one is a P220 I had them refinish around 1997. I shoot it all the time and it looks perfect to this day. I had them refinish a P239 in NP3 that was my EDC for years and years, no signs of wear today. I had to have them redo that one after a few years when my sweat (probably pH level) discolored the slide. But they're 10 minutes from my house and they were happy to redo it at no charge.

That's fascinating information Q, thanks for the follow-up and compiling it in a new thread.

Great info, thanks!

There's a nickel P226 at a shop near me that I've been eyeballing. No box or bonafides sadly, though it does look like an original Klein plated gun based on color.

great job getting us those answers that have never been fleshed out 12131...

I have had several pistols EN'd by Klein Plating since having my first P226 done in 1987...

I never could locate any "factory" EN pistols and upon talking with SIGArms in Herndon, VA at the time I was told ALL SIGs (at the time) arrive here Blue'd and those we wanted EN'd went to Klein.

I sent a P226 in 1987 and no longer own it...I learned that the last owner had it converted to a simulations pistol...sad to hear that but it still works with no visible damage when last I saw it (maybe 10 years ago)

I then sent the P228 12131 mentioned after buying the first one I could lay my hands on in 1990 or so...it is still up and running although I do notice some minor EN peeling/flaking on a rail...this pistol has had a number of rounds through it during it's lifetime...

I also sent a P220 in 1994 and the current owner says it still runs fine but he noticed some minor EN peeling/flaking on the rails but again this pistol has had a lot of rounds through it and I cannot attest to spring replacements after my ownership.

I currently have a P220 that a co worker of mine owned...we bought ours at the same time and sent them to Klein's at the same time in 1994...the frame looks just fine (my co worker had the slide K-Kote'd and that was in poor condition so I sent the slide to CCP for their CCP II finish and the P220 resembles the configuration of the P220 I used to own)

Good luck with your pistols...and great job 12131

Bill

This message has been edited. Last edited by: SiGagain,

I'm going to side with Bruce on this, for several reasons.

I routinely treat aluminum alloys, generally with a chemical treatment rather than anodizing because anodizing has several disadvantages with regard to strength of a part. When I treat, I use alodine (which can also reduce structural strength, but is approved for my purposes on aircraft). It first involves mechanical then chemical stripping of the existing oxidization layer on the surface of the alloy part.

Aluminum is highly corrodible. It naturally forms a layer of oxidation on the outer surface, and when aluminum sheets are produced, they're finished with a layer of aluminum that's there to oxidize (alclad, or aluminum-clad) to protect the sheet. While we'll remove that and alodine a part prior to coating it with an additional protective paint, we don't plate and we don't do that to high tolerance parts.

To mechanically strip a part, either by friction using abrasives by hand, or by bead blasting, even with media that's not supposed to remove material; the actual dimensions of the material will be changed, and the surface will be impacted, changing its properties. Additionally, there's a probability that certain of the medial will be embedded in the alloy, which can lead to other corrosion and stress problems.

A formed part such as a machined or cast frame, machined to a tolerance, will have that tolerance compromised and removed, along with media embedded; the material is left uneven and pitted, and when the chemical stripper, an acid, is applied, certain of that can remain in the material, leading to longer term corrosion. Additionally, in the case of anodizing, removal of the anodized surface changes the surface hardness. The properties of the part are altered. Surface hardness is not just about wear. It's also about strength of the part. It may not only be wear that occurs; cracking may also result.

The theory is that replacing the material thickness with the "lubricity" of a coating makes up for the lost material and restores the tolerance, and acts as a barrier to wear, but that's a junk science way of viewing it, more of a sales spin on what's really an aesthetics job, not a mechanical job. Those like Robar who defend stripping the frame are giving their input from the perspective of salesmen, and what they're selling is an image, a good looking job. They are unquestionably reducing the strength of the part and changing its properties and while the NP3 (et al) may reduce wear by reducing friction, and may be easier to clean, it does not restore the hardness to the surface (neither does hard chrome, which lies over the surface (and bonds to it) but is not a part of it. One may think of removing the exoskeleton of a bug, then painting the bug. The exoskeleton and the strength is still diminished or gone, though anodizing is more akin to surface tension on water, in terms of the relationship to the material...except in this case it's on an aluminum alloy).

How the frame looks doesn't tell you what is happening at the molecular level, which is what actually counts: it doesn't tell you about the strength of the pistol. Experience has shown that too often people pick the best looking car, airplane, handgun, whatever, overlooking the mechanical element; people tend to favor image over reality, but simply because the pistol looks good doesn't mean its been improved. In the case of stripping the anodizing off an alloy pistol frame, it hasn't been improved. It just looks that way.

Personally I won't have any of my aluminum frames stripped and refinished. CCR is correct not to strip them, and Bruce is correct to advise against it.

On a related note, hard chrome was a popular choice for a long time, not so much now, but it's worth noting that associated with chrome application on steel is hydrogen embrittlement, which also changes the properties of the metal. In many applications, it doesn't matter much, but in critical ones, it can. There have been cases in which the builders of experimental aircraft chrome plated the control stick in the cockpit, only to have it snap off, due to embrittlement of the steel, and there have been cases of parachute rigs with three ring releases and harness fittings that failed due to chrome plating, and embrittlement.

It looks nice, but whatever you do to the surface of the metal can, and often does change the property of the part. In the case of a soft alloy, removing the factory anodizing is a poor choice. Chrome plating a thick piece of metal like a slide may not have a lot of effect, but so long as people are more interested in looks, nobody will care so long as it looks good. I won't be doing it to my pistols.

You know this will never end the discussion.
As a side note, Angus Hobdell at the CZ Custom shop says that CZ alloy frames are not anodized but are polycoated. Is this going to be a major shock to all our CZ fans and cause a mass sell off? I think not.

I much appreciate the more specific information on this oft discussed subject provided by Q and sns3guppy.

FWIW, years ago I was acquainted with Robbie Barrkman of RoBar. They were doing a fair amount of SIG refinishing back then. In fact, I once saw, what appeared to be perhaps hundreds, of new SIG frames at RoBar waiting to be finished for SIG. Robbie said it was some sort of test contract to apply one of RoBar's finishes. Even though Robbie did his Np3 back then, he told me that he did not recommend stripping the factory frame anodizing to apply his NP3 finish. I recall seeing the RoBar "Norton Special" finish on SIGs back then,i.e., factory frame anodizing left intact and ferrous parts plated with NP3. In any case, I always remembered Robbie's advice, and never considered removing factory anodizing from a SIG alloy frame to apply another finish.....ymmv

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Originally posted by ace73:
You know this will never end the discussion.
As a side note, Angus Hobdell at the CZ Custom shop says that CZ alloy frames are not anodized but are polycoated. Is this going to be a major shock to all our CZ fans and cause a mass sell off? I think not.

He he. Not just polycoated, but not the entire frame is covered with it. We SIG fans are the only folks in the fiream world who are obsessed about that SIG frame and rail, it seems.

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Originally posted by sns3guppy:
Those like Robar who defend stripping the frame are giving their input from the perspective of salesmen, and what they're selling is an image, a good looking job.

Your post is very informative 'SNS3guppy" but, just to be clear, when I had Robar nickel plate my P228 frame they did not defend stripping the anodizing. They advised me that they had to strip the frame in order to apply the electroless nickel and did not say it was either good or bad, they let me make the decision.

Some additional tidbits of information.

Anodization: Roughly speaking, for every 0.001" built up with anodization, it also penetrates into the host surface by 0.001"
So when anodized surfaces are stripped, your part will always lose material.

Hard Chrome: Hydrogen imbrittlement is real, however there are simple processes used to deal with it. In most cases after hard chrome plating where ultimate structural integrity is the goal , the parts are baked at ~ 300 F for hours which drives the free hydrogen out of the host material.

quote:

Originally posted by sns3guppy:


A formed part such as a machined or cast frame, machined to a tolerance, will have that tolerance compromised and removed, along with media embedded; the material is left uneven and pitted, and when the chemical stripper, an acid, is applied, certain of that can remain in the material, leading to longer term corrosion. Additionally, in the case of anodizing, removal of the anodized surface changes the surface hardness. The properties of the part are altered. Surface hardness is not just about wear. It's also about strength of the part. It may not only be wear that occurs; cracking may also result.
.

Removing anodizing properly is not done mechanically or with an acid.

Anadozing does not add strength, adds a bit of wear resistance and increases corrosion resistance. The main reasons it is used is it is cheap and looks nice. Electroless nickel is a superior finish for aluminum.


Hydrogen enbrittlement in 2018? The few shops doing hard chrome know how to deal with this issue.

quote:

Originally posted by mbacker_99:
Hydrogen enbrittlement in 2018?

Yes.

Neither physics, nor chemistry has changed, despite the advanced modern age.

Gravity still works too, in case you wondered.

I always thought that after hard chrome plating, the part is baked to relieve hydrogen embrittlement. I would think the shops know that.

Interesting topic Q. I'll ask if frames were plated EN, was there not some mention a few times here of a copper plate first applied ? I know little of this process. Great post by sns3 also. I recall print dimensions being altered for plating, such as holes for pins due to build up. I cannot recall the name of this tolerencing. Its been a few years sinse I've had to calculate this. I'm rusty. Pun intended.

quote:

Originally posted by sns3guppy:

quote:

Originally posted by mbacker_99:
Hydrogen enbrittlement in 2018?

Yes.

Neither physics, nor chemistry has changed, despite the advanced modern age.

Gravity still works too, in case you wondered.

Yes and any plater worth his salt in 2018 knows how to tackle hydrogen enbrittlement.

This message has been edited. Last edited by: mbacker_99,

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Originally posted by David Lee:
Interesting topic Q. I'll ask if frames were plated EN, was there not some mention a few times here of a copper plate first applied ? I know little of this process. Great post by sns3 also. I recall print dimensions being altered for plating, such as holes for pins due to build up. I cannot recall the name of this tolerencing. Its been a few years sinse I've had to calculate this. I'm rusty. Pun intended.

many mention copper as it is used under the shiny nickel but EN does not require it and I've never read where a plater has used copper under their EN coatings...

Bill

quote:

Originally posted by mbacker_99:
Anadozing does not add strength, adds a bit of wear resistance and increases corrosion resistance

This contradicts what SIG engineer Ethan Lessard wrote me when I went through my frame saga:

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The Hard Coat provides the hardness, and therefore the strength of the frame structure to retain its shape.