Posted: 6/23/2007 5:25:23 PM EDT
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I am thinking of replacing my Emerson La Griffe with a titanium one. The main reason for this is I wear it 24/7 and mine has become pitted and is frequently rusty. This is no fault of the knife. Sweat collects in the kydex sheath so the knife frequently sits in a puddle of sweat. Is titanium completely 100% rust proof? Stain and corrosion free? What would be the pros and cons of using Ti in an everyday work knife? |
Rust = Iron Oxide. I'd say Titanium is rust proof since it doesn't have any iron in it.  I have had a Titanium watch for about 5-6 years now and it the metal has not corroded at all despite being on my wrist with a layer of sweat frequently beneath it. So no you won't have to worry about corrosion with titanium. However, I'm not sure how well it will hold an edge compared to steel. They are two different metals and while titanium is as "strong" as steel, it has different flexing and sharpening properties and stuff. |
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I recently saw this at a knife show and a buddy of mine bought one. A pretty cool Ti neck knife. miltner-adams.com/products/ma-2_ti-neck2.html |
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Ti alloys are typically pretty soft. Tough, but soft. I think about the hardest they can be gotten is about 45 RC. They are also a BITCH to sharpen again (and they will need frequent re-sharpening if you use them a lot.) Ti knives were first developed for EOD personnel who needed a knife that could be used around magnetically sensitive mines and explosive devices. An absence of magnetic signature trumped edge holding capability and the Ti alloys used are better than the previous beryllium alloys used in prior EOD knives. Get the rust off your existing blade and them thoroughly degrease it. Then get yourself some high grade lithium teflon grease such as tetra gun grease and rub that stuff into the steel, wipe off the excess, repeat, repeat, etc. for several days. This will work the grease into the pores on the surface of the steel. Periodically clean and re-oil/grease the knife blade. The steel used by Emerson is only nominally stainless. Just barely over the minimum chromium content to qualify, thus a bit of sweat will cause it to rust and stain if not properly treated. I oil or grease my carry knives about weekly or whenever I really grunge them up and need to clean them really well. I may even dissassemble the knife to detail clean the whole thing and really get the blade clean and properly protected. My Emerson CQC7 lives in my pocket and gets all manner of sweaty; since I started keeping it properly protected, it hasn't rusted on me. |
The only thing I remember made of Ti when I was in EOD was a prober for de-mining. All of our low μ tools were made of that "fantastic" metal known as Beryllium, we kept those tools wrapped up and in the Arms room safe so no one could use them. 
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One thing has to be made clear about a Ti knife. They are made for one purpose and one purpose only. Defend your life. They are not for everyday cutting or utility purposes. To defend your life with a knife they only have to be sharp one time. Then you can wipe the blood off and resharpen it. Just sayin. |
| Get a stainless steel blade, you'll have to try really hard to get these rusty. There are several grades like ATS-34 that hold an edge very well. Just don't throw them into wood or use them as a pry bar, this type of stainless is brittle. I've recently had mine in salt water most of the day at the ocean, no rust. SS blade, titanium/fiber handle. |
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Here is the correct answer Talonite look at the now discontinued Camillus Mini Talon Talonite is some kind of dendritic cobalt corrosion proof amazing cutting ability due to micro carbide crystals or something. I have a mini and wish i had a regular. They are Rob Simonich designs (RIP)  |
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I have a titanium (beta alloy - which I think is a little harder) knife for diving. I stopped cleaning it for a while, just to see what repeated and prolonged immersion in salt water would do to it. The knife is perfectly fine - no corrostion or stains, and it didn't affect the edge. I've had it for about five years now, and taken it on over 100 dives. However, I did discover that the "button" at the end of the tang was steel, so that corroded quite a bit. I guess that made it a good test of the titanium, because I got to see what happened to stainless steel under the same circumstances. So the titanium blade should be fine - just make sure there aren't any other regular steel parts in the knife (like screws, etc.), because you'll still need to keep an eye on those. |
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My dad works with titanium tools for oildfield stuff. Its EXTREMELY hard to machine or grind (translates to sharpen) and it isn't very hard. Its great because it does not tarnish or have any magnetic field. I have a few nice pieces of it on my desk (broken parts that he takes home for me) Its VERY light too, but you have to watch out with the edge. If you can find one, i would personally re-edge it to 30 or even 35 degrees!!! most knife blades cutting edges are 20-25 degree's. This will help hold the edge, but it will require far more sharpening with more rigorous use. Titanium is still my favorite metal 
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I occasionally have to analyze titanium alloys at the lab. Titanium is impervious to nitric acid, hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid, etc. It is readily attacked by hydrofluoric acid. About the only consumer product that contains hydrofluoric acid is Wink rust remover, which is available virtually everywhere. (wal-mart, home depot, etc) But even in aqua regia (combination of nitric and hydrochloric used to dissolve gold & platinum) titanium is untouched. Don't worry about it staining, tarnishing, corroding, etc. Ain't going to happen. Interesting note: Titanium can be "anodized" to a purple color if connected to an electrical current in a phosphoric acid solution. |
Not sure what beryllium has to do with titanium, but I thought I'd add that a lot of machinists at a local munitions plant died of cancer because they were milling beryllium metal and alloys for nuclear arms. Beryllium is terrible terrible stuff. I occasionally have to test beryllium bronze springs. Not much risk since I don't create any dust, and I handle them with gloves. |
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Beta Ti Knife I have the fixed blade for a dive knife. Look at the folder on the bottom. Its stronger than 420 Stainless its made from Custom Formulated Titanium and it can and will not rust. Invisiblesoul |
Iceman made mention of EOD using Ti for it's low magnetic qualities however the low magnetic tools we used when I was in were made of Beryllium. Beryllium is used in nuclear weapons for its neutron reflector qualities but it is a nasty metal to deal with. |
That's the exact knife I have too - mine is the double-edged, blunt-tip version. |
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If its a knife to defend yourself, it's perfect. It's a pain to machine to tolerances, and won't hold an edge as well as steel. The human body won't react to Ti, so when machining, you have to be really careful. If you get a shaving of steel or brass under your skin from milling or whatever, the body will usually attack it and blister around it, eventually expelling it. Ti doesn't have that reaction (hence it's use in medical parts). Which means, if you don't kill the perp, that knife might just disappear inside him! 
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Even the best stainless steels rust if not cared for. Simplified, it is always a trade off between holding a good edge, which requires metal ingrediants that can rust, to make it hard) or super rust resistance softness, which makes for a lousy edge holder. In knives, titanium is sometimes used as a replacement for very stain resistant soft stainless steels. Since neither can generally hold an edge worth a damn (relative to hard, high carbon SS), might as well have the imperviousness to rusting and the additional weight reduction of titanium. Two ways to increase (not completely prevent) the rust resistance of any steel knife is: a. painting (guns often are done this way) b. Polishing. Painting is much more rust resistance method, but tends to be less pretty as bare metal. No you don't need special "gun" type paint. Plain ol' spray paint will protect metal very well and with a good prep, can be very presentable in looks. Polishing, doesn't necessarily prevent rust, it just changes the behavior of rust-accelerating fluids on the blade. Rust resistant SS blades really are helped by full polishes relative to carbon steel. Fluids on highly polished blades tend to just run off before sitting around long enough to rust it up or they run and pool at the sharp edges to do their rusting work; not on the eye offensive flats of the blades. Unfortunately, high polishes of blades is very time intensive and with everyone wanting "tactical" dull stuff, polishes are getting unusual to see. Manufacturer's don't mind. It makes it cheaper for them. It's takes approximately 4-5 times the labor time to go from a 600 grit finished surface to a full polish than it does to go from rough to typical 600ish grit level blade finishes. Full polishes also demand no imperfections in the blade as they will show. FYI: the stone washed, 600ish grit dull finishes on all these tactical blades promotes hard-to-fix rust on them because the microscopic uneven surfaces, pool and hold rust accelerating liquids and crap. In addition, the rust in these tiny pores, tends to pit the metal much more (if not cared for) versus just evenly light surface rusting as a polished blade does. If you like the knife you have, just paint it with plain ol' Rustoleum (if you're cheap) or send to a gun painter for something like NP3 and increase it's rust resistance by a factor of 1000. It's cheaper than a new Titanium knife and will hold a better edge. Just my opinion of course. |
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This is what you want: SOG SEAL Pup Elite  This is a Hardcase Black TiNi blade designed for extensive and prolonged use in salt water/ocean environments. |
Awesome knife, but not exactly a good neck knife. |
Very much correct, especially the second paragraph. I deal with surgical instruments, and nearly all of them today are a "matte" finish, as opposed to a full polish (as mentioned, it is cheaper for the manufacturer and increases profit margin). Fully polished stainless is far more corrosion and rust resistant than the "matte" versions. Before you plunk down the cash for a Ti knife, have your blade polished to a mirror finish (by a professional) and you will notice how much less it will develop rust and pit. Like others have said, Ti won't hold an edge worth a damn, and is only useful for a life and death scenario, not daily use. Titanium is a great metal, but it isn't the be all end all. |