Letter 32469

Melonite vs Tennifer on semi-auto pistol slides

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Where would I find a Side by side comparison of Burlington's Melonite Process and the German Tennifer Process? I am often involved in arguments regarding the these two finishes on Smith & Wesson and Walther forums. Both Companies produce a version of the same Walther Designed 99 pistol (Walther Tennifer over Steel and Smith amp;& Wesson Melonite over Stainless steel.) Because of the success and reputation Tennifer gained after the Glock Pistols were introduced to the U.S. market some years ago, Tennifer seems to have gained the reputation of a indestructible miracle finish unable to be duplicated in America. I say this attitude is wrong and American finishers know just about as much about super hard firearms finishes as the Germans on their best day. Smith & Wesson didn't just pull Melonite out of a hat. The Engineers at Smith & Wesson knew that Melonite over Stainless, was a pretty advanced finish for Firearms slides. So help me out guys. I may be right. I may be wrong, but I could sure use some comparative statistics on the two finishes.

Jim Davis
Hobbyist - Enid, Oklahoma

From what I understand - Teniffer can't be applied in the US because the EPA won't allow it.

I was a project manager for a manufacturing facility - and we wanted "tennifer" like qualities applied to some steel parts - and after tracking down the facilities in Europe that apply the tennifer finish (it is not a Glock exclusive) - those companies told us they couldn't set up shop in the US because the EPA wouldn't allow the teniffer process to be done here.

So - that would make the "Melonite" process different - as it can be done in the US. How different - I have no idea. More importantly - if there is any *practical* difference between the finishes?? That is the $64,000 dollar question...that I don't know the answer to.

Jones
- Odgen, Utah

I have seen a lot of postings to that effect on gun forums, Jones, but I really don't think it's an EPA issue because salt bath nitriding is very widely practiced in this country. I still believe it's a licensing issue and that those shops may have been bending the truth a wee bit.

I would suggest that anyone who is interested in this process may wish to speak to Brian Radford of Kolene (a supporting sponsor of finishing.com, located at http://www.finishing.com/Equipment/kolene.shtml, or at least review their paper on the QPQ process at http://www.finishing.com/kolene/qpq/index.html.

Ted Mooney finishing.com Brick, New Jersey

MELONITE IS ANOTHER WORD FOR TENIFER. THEY ARE THE SAME EXACT THING! YOU CAN DOUBLE CHECK MY ANSWER BY SIMPLY TYPING "MELONITE ENCYCLOPEDIA" ON THE GOOGLE SEARCH AND BE ABLE TO LOOK IT UP YOURSELF FOR VERIFICATION.

Christopher Deleon
- Palm Beach, Florida

Thanks, Christopher

At www.durferrit.com/en/unternehmen/firmengeschichte.htm, Houghton Durferrit -- formerly part of DeGusa, but now a division of H.E.F. -- claims both trademarks and says they are the same thing. If they own the tradenames as they claim, they are free to decide how the processes are done, including whether they are identical or not, just as Ford has been free to make a "Thunderbird" a 2-seat sports car, a 4-seat luxury car, or a 6-seat family sedan to suit changing times.

Similarly, the same page claims that the Tenifer and Melonite process "has undergone continuous development with regard to its regenerability and ecology". So neither is quite what it was in the past.

Ted Mooney finishing.com Brick, New Jersey

The only difference in the "Tennifer" process and "Melonite" is the brand name.
But the original German formulation for the "Tennifer" carbonitriding salt bath used 60% sodium cyanide and cyanate and 40% potassium cyanide and cyanate.... That's why the EPA wouldn't let anyone do it here.
The process has to be cyanide free here.
As far as I can find out, some places in Europe are still using cyanide salts.

Mmmmm....smell the vapor coming from that vat of molten sodium cyani..i...... thud!

Edward Baltzer
- Birmingham, Alabama

Thanks, Edward, but can you quote an EPA reg that says this? I'm not saying you are wrong, but I am saying that we've received countless postings saying "the EPA doesn't allow . . ." that have been in error.

Ted Mooney finishing.com Brick, New Jersey

The Tenifer process is not exclusive to Glock. In fact SAAB of Sweden once used the same process for it's cam and crankshafts. The main difference between the Tenifer and Melonite processes is a matter of splitting hairs. I believe that it is simply an EPA issue, in two seperate processes, each having the same end result.

Jeremy Shank
- Atlanta, Georgia

Okay, so if these two processes are the same, how come I've seen Smith and Wesson firearms that are Melonite treated rust/corrode, but Tennifer doesn't? A friend of mine has carried both guns concealed and his Glock 26 never rusted, but his M&P 9 compact did? Through practical experience, I have to disagree that they are the same. They react differently when they are placed in the same environment.

Todd Heimann
- Cincinnati, Ohio

Just because they are the same finish doesn't mean they are applied the same way. Company X might have done a bad job of applying the product. Perhaps they had a bad batch of the product?

Levi Gresser
- Baltimore, Maryland

Thanks in advance,
My question regards the Melonite/tenifer debate and actually is quite simple. My understanding of this salt nitriding acid bath process is that it doesn't translate well to stainless alloys, that it actually weakens their ability to withstand corrosion? Would this perhaps explain why were seeing the S&W product developing oxidation?

Chris Edwards
- Roseville, Minnesota

Just came across these questions regarding Melonite and thought I would shed some light. As the former engineering Manager of S & W I can tell you that we chose Melonite for several reasons, one being durability and the other that it could be used on both 4140 and 416 stainless. However, I don't recommend it for the latter because it actually removes some of the properties of the material, which ultimately could allow for rust/corrosion.

The facility we selected is located in the Mid West (no secret there) and let's not give Gaston Glock too much credit, the tennifer finish has been used by the German automotive industry for years, including BMW and Mercedes.
I will give him credit for taking a very traditional industry and introducing a great product using simplicity and light weight materials (Original patents for many of Glocks design were filed in the 40's, years ahead of its time)

Hope this helps.

David Sargeant
- Coral Springs, Florida

December 31, 2008 David, Like Crazy Einar I give Gaston Glock kudos because when he put down his ideas for gun designs he didn't know anything about it ... so he didn't have any preconceived and "traditional" notions of what goes into it. Therefore he looked around and added the best technology available to do the best job. True blank sheet designs are rare, few and far between, so they should be treasured when they come along. J. Michael Antoniewicz II - Greensboro, North Carolina February 2, 2009 Is anyone here familiar with austempered ductile iron (ADI)? this process uses a salt-bath process, too. The material is used for crankshafts, suspension parts and whatnot--exposed to stresses not unlike guns. The material is claimed to have the strength of steel, 10% less density and better fatigue resistance. It's easier to machine than steel. Is this used in any handgun, to anyone's knowledge? Adam C. Sieracki - Calgary, Alberta, Canada September 29, 2009 Since the Melonite process subjects the work piece to temperatures of 580º C (1076º F), and since this is hot enough to alter the crystalline structure of the metal and thus the metal's previous heat treatment, is Melonite safe to apply to actions and barrels that have already been heat treated? I have a barreled action for a bolt rifle that I'd like to have Melonited, but I'm concerned that doing so will compromise its properties. Recommendations? Felix Strange - Oakland, CA, USA