Ray Rogers Handcrafted Knives
My LiquidMetal(R) Adventure
Recently, I was able to acquire several bars of LiquidMetal(R) and looked forward to seeing if maybe I could be the first to make a folder blade out of this material. I had read the Blade article (May 2003) on R. W. Clark's knife and picked up a little of his enthusiam for the material.
Having worked with other non-ferrous blade materials such as Stellite, Talonite, and Cobalt 6BH I had some idea of what to expect. But, none of those materials is a grainless homogeneous material with no carbides - more similar to a metallic glass than a metal. Like those other materials, LiquidMetal(R) is non-magnetic and non-ferrous. It can't rust and it requires no heat treat. In fact, heating it up beyond about 700 F ruins it by causing it to acquire a grain structure!
I tested a piece with my Rockwell tester and found that it seemed to be about Rc 53. That may seem soft to you guys who make handmade knives but it really isn't that bad. Many commercial knives are about that hard. I checked a Chicago Cutlery steak knife and found that it was also 53 and it's a pretty good knife. I'm guessing that many Chinese and Pakistani knives aren't even 53 so this isn't a bad starting place.
Just for grins, I decided to see if I could anodize a piece of LiquidMetal(R). It contains a lot of titanium so it seemed like it might work. If you have ever tried to anodize a piece of titanium that had a piece of foreign metal attached to it (like a pressed in pin, a steel detent ball, or a screw) then you probably already know what happened. It took a lot more voltage than usual and the wetting solution tried to boil. There was a slight color change toward gold but I blew three fuses getting there. Oh, well.
Normally, I would profile a folder blade and then put it on the surface grinder. But, this stuff is non-magnetic and won't stick to my magnetic chuck. So, I built a steel jig with clamps to hold the LiquidMetal(R) bar by the ends, surface ground the middle, and then cut off the ends with a 14" cutoff saw. This material is cast so it comes out of the mold smooth but it does have some sprue marks on it and I felt that surface grinder was necessary to guarantee flat, parallel sides.
Then I coated the piece with DyeChem so I could scratch a blade outline on it. I drew two folder blades on this piece. Now, all I had to do was cut the piece in half. I knew this wouldn't be easy because the material is already as hard as it will ever be. First, I tried a bi-metal blade on my bandsaw even though I was sure I knew what would happen. It cut about 1/4" and I needed another blade. It really feels like glass under the blade.
Then, I switched to a hacksaw with a fresh bi-metal blade. This seemed to work better for some reason and I made it about half way through the bar before I got too worn out to continue (I'm old). After that, I went to an air powered 3" cut-off wheel. That took a little time and a lot less effort and eventually it got through the bar.
Now, remember what I said about the 700 F ? The cut-off wheel creates a lot of friction. Even though I was cooling it with water there was some evidence of melting. But, as this wasn't really close to the blade outline I wasn't worried about it. LiquidMetal really loads a belt and most of it does not clean off no matter what you do.
When we start to profile a blade most of us start with and older, worn belt and use that until we get close to the blade outline. That's how I started. I was amazed! It cut like butter! At first, it seemed like you were grinding on a hard piece of glass and nothing much was happeneing, then suddenly, it was like butter.
That threw up a warning flag in my mind.
A quick look at the back side of the blade explained the situation. Can you imagine what it would look like if you tried to grind a thick piece of polyurethane plastic with a dull belt? Well, that's what it looked like. There was a jagged, melted, ridge about 1/4" tall all along the area I had ground - and it was sharp as broken glass in some spots. So, Rule #1: use only fresh, sharp belts and a very, very slow grinding speed. Yawn.
OK, switched to a fresh belt and ground more slowly. Frequently dipped the blade in water to cool it. Incidentally, this material is about 41 % titanium if I recall correctly and hot titanium is very exothermic. It will very quickly dump any heat it has into anything it touches. I grind bare handed so I can feel the heat buildup in the blade. Rule #2: when you think you are starting to feel a little warmth in this material, cool it off because in another two seconds it will feel red hot.
By the way, as I ground I noticed very little dust collecting in my dust pan. What dust there was looked extremely fine. Now, the gasses that come off titanium are bad enough and this stuff has other metals in it that may be worse for you. The small amount of dust and low melting temperature suggest to me that this material may be sublimating directly into gas. And, the powder you do get is so fine that it is easily air borne so, Rule #3: wear the very best respirator you can find.
Eventually, the profile was done. Now I needed to drill holes for the pivot and for the thumb stud. This actually wasn't too hard to do. At least, it wasn't hard to do as long as you happen to have a $45 Hi-Roc carbide drill bit and lots of lubricant. The holes were extremely clean.
An interesting thing happened when I went to mark the position for the holes on the blade blank. I use one of those spring powered punches to put a little dent in the metal where I want the center of the hole to be. Whenever the punch would snap and put a dent in the metal it would throw a spark. Every time. The tip of this punch is mild steel. I also noticed when grinding with a fresh belt that it would make a lot of little bitty sparks. So, Rule #4: don't make one of these blades for a military guy or anyone working around combustible gasses or materials - which is one reason these people ask for non-ferrous blades in the first place.
This was one of my Warlock blades to it needed some thumb grooves cut into the thumb ramp. This would normally be done with a checkering file but have you ever tried to file a piece of glass? This feels just like that - ain't happenin'. So, a tiny diamond coated cutoff blade in my mini-mill was used to make a grooved thumb ramp.
Now for the sad news. The blade is completely finished except for grinding the bevels which I usually leave until the knife is completely functional and tested. I put the blade in the handle and carefully adjust the lock work. I test the opening and closing. It works smoothly, locks up solid when it's open, and snaps closed when the detent ball catches the blade. Just one small problem - it squeaks like a banshee!
The ceramic detent ball I used was riding on the side of the blade - like it should - but it was squeaking like fingernails on a blackboard. Maybe it was a glass on glass kind of situation and if I had used a metal ball maybe that wouldn't have happened. Anyway, I tried a drop of oil, then White Lightning wax lubricant, and finally a blob of grease. All these did was change the pitch of the squeak.
At this point I might have tried to change to a steel detent ball except that I noticed something else that was uncool. The track where the ball rides on the side of the blade is normally just a polished looking arc. But, on this blade it was a ditch. The ball was rapidly digging a channel in the side of the blade.
I'm guessing a steel ball would do that too. So, I took my Dremel and tried to dig out the channel hoping that if I got it clear of the ball that the hysterical shrieking would stop. The noise did let up although it never did quit altogether. Unfortunately, the detent naturally quit working correctly as the metal disappeared from around the detent. I don't want to ship knives without a properly working detent!
I tried 3 other blades in the handle just to be sure, one each of D2, BG-42, and CPM 440V. None of them squeaked. Nothing is impossible, or so I believe, but some things are not advisable. Right now, a LiquidMetal(R) blade in a liner lock folder doesn't seem like a good idea anymore. If you solve the detent problem I believe you'll find that slamming against a stop bar will dent this stuff pretty quickly and the knife will get loose. Perhaps some other design will be better for this material, a design that doesn't have anything to wear against the blade, but I'll leave that for the next guy.
Undaunted (or maybe just a little daunted) I proceeded to start the next knife. The project was to be one of my 10" Cherokee Chef's knives and for that I had a bar of LiquidMetal(R) that measured 2" x 15" x .135", just right for a full tang kitchen knife. After cutting the two folder blades apart I had arrived at Rule #5: buy your bar of LiquidMetal(R) as close to the size of your blade blank as possible.
Profiling the tip of the blade wasn't too hard to do as there wasn't much material to remove. With steel, I would have cut out the area under the handle on a bandsaw but I think you already know why I didn't try that this time. Instead I ground it away. That took some time and thoroughly wore out a new 60 grit Norton Hogger.
Now to flat grind the blade. To make a long story a little shorter it took a fresh 60 grit belt to do each side of the blade. It also took a long, long time. At least it seemed long to me and I'm used to grinding those same blades after I heat treat them. The necessity for keeping the metal very cool adds quite a bit of time to the grind. But, the grind went without mishap and I was nearly finished tapering the blade when I had a little problem.
Of course, I knew that the tip of a tapered kitchen knife blade would be very, very thin so I was proceeding with great caution so as not to over heat this stuff. Bare handed, fingers very close to the tip, I would touch the belt for two seconds or less and then cool it in water even though I couldn't feel any heat yet. Then, without any warning, the first 3/8ths of the tip bent away from the belt about 30 degrees. Just bent, no discoloration, nothing looked melted. Obviously, I got it too hot but it was very strange to see the metal run from the heat that way. I don't believe that I bent it, I really think it did it by itself. I could not get it to bend back, it was very springy. After trying to straighten it for about a minute the tip broke off. Fortunately, it wasn't difficult to regrind the tip as long as I was super paranoid about the heat build up.
In due course, the blade was finished and the handle attached and shaped. Although I didn't mirror polish this blade it does appear that this material will take a mirror polish without any unusual amount of effort.
While testing before I tried to apply the maker's mark to the blade I learned Rule #6: cut your marking dwell time in half. This material marks very easily using the electrolyte for stainless.
The finished blade sharpened very easily and felt very much like sharpening a piece of titanium. It took a very nice edge, very sharp. I have no idea how well the knife may hold an edge as I sold it within a few minutes of putting the edge on it. I believe that it will perform like you would expect a knife with an Rc 53 blade to perform and be very adequate for kitchen service. The blade did have substantial flex to it so I think a field knife made from LiquidMetal(R) isn't going to be easy to break as long as you don't make the tip too thin. Other than that, I couldn't tell it wasn't a steel blade just by looking at it but it did weigh a little less than a similar steel knife would have.
CONCLUSION:
The ability of this material to be cast into a finished blade will probably be its biggest selling point to the commercial cutlery industry. That, combined with its extreme stainless qualities will likely make it popular for mass produced kitchen cutlery.
But for the custom knifemaker I believe LiquidMetal(R) will have only a very limited application. The problems for stock removal makers that I have described above can be overcome in time, but why? The high price of the material and the cost of working with it seem to more than outweigh the savings in time and money that come from not having to heat treat the blade. So, while it's good to have another material available to us for those special situations where a non-ferrous knife is the solution to a problem the fact that the blade's performance isn't superior to steel, or even a match for steel, will keep it from wide spread use among custom makers.
Finally, when molds are available and custom makers can have a mold made and have their blades cast, why would they? At first glance, it would seem to be a similar concept to having your blade blanks laser cut. Laser cut blanks remove some of the hand crafted flavor of the knife in my opinion but it does save some time and money. Cast LiquidMetal(R) blades also save time and money by coming out of the mold with an acceptable finish already on them and even already sharpened. They only need a handle put on to be complete - and there's the problem. If you make your knives this way it's no different than buying a kit blade from a supplier except that the blade will be your own design. If you do that, and I do that, then the finished knives may not look the same but they will perform exactly the same (assuming similar sized blades and the same edge geometry). In other words, the critical factor in blade performance - the heat treating - has been removed and all knives are now equal. A knife made by a Really Big Name maker will hardly be any different and carry no additional guarantee of better quality or performance than a knife from a first time Newbie.
LiquidMetal(R) is not a bad blade material. In fact, it may turn out to be better than the other non-ferrous materials in some ways. LiquidMetal(R) has it's place like the other non-ferrous materials but it is not a general or superior substitute for a steel blade in the majority of cutlery applications.
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Ray Rogers Handcrafted Knives
