CORROSION resistant COATINGS for all steels

Cobalt

Cobalt

Platinum Member
Joined
Dec 23, 1998
Messages
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The following involves a question to ALL manufacturers using coatings on their blades.

Are the coatings used on YOUR knives highly corrosion resistant or not?

First of all, lets set some parameters. A good corrosion resistant coating has to be a VAPOR BARRIER to MOISTURE. There is no way around this. If your coating does not provide a vapor barrier to moisture, then it does not provide significant corrosion resistance. A good example of this is Hard Chrome and other hard metal coatings(like Ti) that offer excellent abrasion resistance but only a slight benefit in corrosion resistance. On the other hand, coatings like Walter Birdsong's coating offer a considerable amount of corrosion resistance since they are a vapor barrier to moisture. I'm pretty sure that REKAT uses Birdsongs coating.

So what is yours, TOP's, Busse, Livesay, etc., etc., etc.???????

PS: This is not a Mad Dog slam thread so let's not go down that path. There are many good coatings out there and I would like to know what is being used on current knives.
 
Co; what is Birdsong's finish? I seem to recall that it is a baked on moly, but could be wrong. Walt
 
Hi Co, there is no way to stop corrosion of a corrosible stuff in a corrording environment.
But: there are ways to slow down the speed of corrosion to an amount acceptable for the wanted purpose.
So please define the surrounding and the acceptable level of corrosion in what time.
I was (some time ago) in the business of selling (XHD)anticorrosion (pipelines, shiphulls, bridges and the like).
Happy sharpening
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D.T. UTZINGER
 
Walt, Birdsong's coating is used in the petroleum industry as well as in the Gun refinishing. It is great stuff. I think it is teflon base, but am not sure. It is a vapor barrier and has a salt water resistance of 4000 hours.

ZUT, you misunderstand, I am not specifying a requirement and I am not seeking to learn about corrosion, as I probably no more than most people on the subject. I want to know what all these different black coatings are. Are they only abrassion resistant coatings or actual vapor barriers to moisture. The knife makers themselves may not even know this. We will find out I guess. If there is no answer then they probably don't know themselves. The mfg of the coating has to provide the specs to the knife company as to resistance and if the coating is a vapor barrier.
 
Cobalt
Yes we use Walter Birdsongs BlackT. I think that the rating for the salt spray is 40,000 hours. BlackT also has some abrasive resistance which is why many MP-5 subguns are totaly BlackT coated then run dry (no Lub)Other qualties of BlackT is it is subsurface so no capillary action. That means the rust can creep between the finish and the blade. Teflon Powder coat, Regular Powder coat and yes Virgina even Hard Chrome are all guilty of Capillary Action. Why because they are surface coating only. We have worked with Walter Birdsong for 5 years and love his work and plan to continue using his finish. There is a lot more to BlackT than I am allowed to say as far as uses and specs.

Bob Taylor

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Some days it's not worth chewing through the restraints and escaping.
 
Bob, your right it is 40000 hours, I miswrote it. It is great stuff but as far as abrassion resistance it is slight but no were near something like HC or Ti coatings. But it has the benefit of much more corrosion resistance. I have the stuff on my guns.
 
Bob, it seems like you may be the only manufacturer out there who knows what his coating can do.

By the way, who is Virginia? And yes Capilary action is a concern in many coatings as is not being a vapor barrier, which most of the metal base coatings are not.
 
Cobalt; what are you worried about corrosion for? I didn't think you owned any steel knives (laughing, ducking, running for cover) Walt

PS 'Virgina' was the little girl who many years ago (1897) wrote a newspaper asking if there was a Santa Claus. The newspaper's editor's reply is a masterpiece of prose:
http://www.barricksinsurance.com/virginia.html

Walt

[This message has been edited by Walt Welch (edited 05-16-2000).]

[This message has been edited by Walt Welch (edited 05-16-2000).]
 
Walt, you are correct. All my knives are made of Kryptonite, no wonder I always feel weak.

I was thinking of Hard Chroming my Stellite blades though
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Cobalt
Ok now I have to ask. Why hard chrome Stellite? Talonite and Stellite are pretty much corrision proof as a blade material can get?
Walt is correct in who Virgina was and for those of us in our Golden years it was a saying that was pretty common.

Bob Taylor

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Some days it's not worth chewing through the restraints and escaping.
 
I am pretty impressed with the performance of Benchmade's BT2, which is based on Birdsong's BT coating. I don't know how different they are.

When I first recieved a M-2 blade from Benchmade for evaluation I rubbed the coating down almost to the metal to see how well it would protect the blade even when it was severely worn, and the blade seemed to be just as well protected in that spot as the rest.

BT2 is relatively soft, it wears off on corners and grind lines just from pocket wear. If you cut much metalic, or high abrasion materials, it can look pretty shabby pretty fast. Seems to maintain its moisture barrer though.

What are people's experiences with Epoxy based coatings? I know they are not subsurface, and therefore might be vulnerable to capillary action, but a coating that can be replaced without destroying the heat treatment if it gets worn or flakey would seem to be an advantage.
 
Bob, I was only kidding about HC on my stellite. It is an old argument from the past in this and another forum.

Storyville, Yes, you can hardchrome it and you would get the reverse of CS san mai, the softer hard chrome on the outside and the harder ceramic on the inside.

Steve, I figured that Benchmades coating was similar since it has the natural lubricity on the surface like the birdsong coating. My Timberline specwar has a much harder and rougher feeling coating on it that is the Ti coating.

Hey Walt, you want to play with a stellite 6K Gerber hunter once Cliff is done playing with it?
 
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