Why not refinish in Melonite?

[nsnate02]

Originally Posted by jacob.sebens

Title says it all. I see lots of people getting their pre-melonite XDs refinished with everything from Duracoat to NP3. Why doesn't anyone get it sent out for melonite treatment?

I'm looking to refinish my XD...what's the best (most durable) option?

If you want the best, get Birdsongs Black-T. It's the only thing special forces and certain government ops use including Melonite and Tennifer guns. That should say it all.

[jacob.sebens]

Originally Posted by nsnate02

Also from what I've read (and this has been discussed in length here), I would wonder if this is the same Melonite as what the XD has. Melonite is a trade mark and I'm not sure I have ever heard of the QPQ addition. It sounds like a similar, but different process.

I'm not a metallurgist (or a lawyer!), but Wikipedia (yes, I know) says that "Tenifer" is a trademarked name for the end result of carbonitriding. It says that Melonite (also Sursulf, Arcor, Tufftride, and Koline) is a trade name for the same end result of carbonitriding. So I think this is the right thing...and considering it's a chemical bath that hardens the outside metal, why couldn't you treat previously hardened steel this way, as long as it was softer than the process would make it?

I'll look into the Black-T...but for curiosity's sake, is melonite/tenifer a better finish than NP3? What about the Black-T? If you were getting the finish of your choice on a new gun, with no concern for cost, what would it be?

[Hooz]

Originally Posted by nsnate02

Simply, you can't. Melonite is done during the heat treating process. It is given a salt-nitride bath prior to hardenening. The chemicals are absorbed into the metal and then it is hardened after that locking in the finish. You can not do this post hardening.

From the link posted earlier:

Melonite QPQ™ is a thermochemical process (ferritic nitrocarburizing) used for the case hardening of iron-based metals. In a molten bath of special salts, nitrogen, carbon, and small amounts of oxygen are diffused into the surface of the steel, creating a super-hard surface, called the "compound layer." Additionally, small amounts of carbon are pulled from within the substrate, toward the surface, creating a "diffusion zone," which exhibits a gradient of concentration of carbon and nitrogen, decreasing toward the core. Thus, the process provides both a hardening of the surface, and a gradient alloying of the substrate, which improves the ductility and overall strength of the material.

That certainly sounds like "Melonite", and they are doing it to "old" firearms. I'd say it CAN be done, and they are doing it.

They also have some more info there about the post-treatment hardness and surface dimensional growth. Very cool stuff. Maybe us non-Melonite XD owners should look into this.

http://www.coalcreekarmory.com/finis...32407edb81 f1e

[nsnate02]

Originally Posted by jacob.sebens

I'll look into the Black-T...but for curiosity's sake, is melonite/tenifer a better finish than NP3? What about the Black-T? If you were getting the finish of your choice on a new gun, with no concern for cost, what would it be?

It is all very confusing! Everything I've read before argues against post Melonite treatment, but these guys say they can. Seems to make sense, but I dunno.

I'd still go with the Black-T. It just has too many praises from people who know and depend on reliable firearms.

Bye the way you will have to call Mr Birdsong. He's an old fashioned guy from Mississippi that doesn't have or need a website. If you do a search his number and address can be found here.

[nsnate02]

Maybe this can clear a few things up. Evidently there is a difference between Melonite and Melonite QPQ, but I'm still not sure exactly what. Burlington is the only company I know of stateside that does this. Here is their link.http://www.burlingtoneng.com/melonite.html

[LTC-USA]

And God created hard chrome, and it was good.

[Tempest]

I have had a 1911 Melonited by Burlington and am happy with the results. The people there are also first rate. I would give them more business except for lack of $ on my part.

I had a discussion with a metallurgist about Melonite and this is what he had to say:

Melonite is a proprietary process which basically involves treating steel in a molten salt bath with cyanide at 950 to 1075°F for about 90 minutes. Yes, this will give a "super-hard" case.

Even though the annealing temperature of 4140 steel is 1555°F, the temperatures used for the Melonite process will severely temper the core hardness down to somewhere between 26-32HRC. That hardness range will give a strong, tough core, which provides a good base for the nitrided case.

The Melonite process will not anneal the base metal nor will it cause crystal growth, it will only over-temper it.

Here is a typical processing cycle for 4140 steel that includes nitriding:

- Rough machine
- Austenitize at 1555°F
- Oil Quench
- Temper at 1150°F
- Finish machine
- Nitride (Melonite)

If you notice, the process requires tempering the part before Meloniting at a higher temperature than the Melonite process itself. This is to geometrically stablize the part for finish machining before Melonite.

Because the hardened case is so thin on the metal surface, you don't want to do any machining after nitriding.

I feel it is quite safe on quality steel guns that are processed by quality shops.

[jacob.sebens]

Outstanding...thanks so much for sharing the first-hand experience. I think this is the way to go.

[Ian Wendt]

I gotta say, I don't understand why some people are so dead-set on saying that it can't be done even when presented with evidence to the contrary.
The ONLY company I've seen that says that Melonite can't be applied after the fact, is Springfield. Which is obviously not true. It CAN be done. It's not cheap, but it can be done. Eventually I plan on having my XD40 taken care of with this. And no, Melonite does not need a covering of oil to prevent rust. It's rust-inhibitive on it's own. Does oil hurt? No.
Phosphate coatings, now those are slightly porous and do indeed benefit greatly from having the pores filled with oil. Melonite, not so much.

[deepdiver]

*looks at Sig P228* Hhhmmmmm