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***YAKIBA POLISHING***
The temper line will seem to disappear as soon as you begin using any sort of abrasive on the blade. It's still there, simply not visible. A mild acid etching will reveal it again. Also, the hardened steel will have a slight golden hue, when compared to the softer part of the blade which appears more gray.

Tangs may still be drilled and reshaped with a file since both tang and spine are soft. If you find a hard spot in the tang, they're easy to anneal.

Tangs are usually a bit longer than one sees in originals. It's easy to trim a bit off, but hard to add some. The Japanese used terribly short tangs on Tanto.

Your blade will have an oddly ground edge when it arrives. It will also be sharp enough to be dangerous. The multiple little grind lines along the edge are there to create a convex shape as you polish the edge. It's basically a Moran edge, rolled a bit to make it dig in to cut better, and to put just a little more meat behind the fragile edge. The small grinding marks will sand and blend into a smooth curve without a lot of trouble, so don't let them bother you. They're supposed to be there on the rough blade. Don't try to sand the blade thin, like a razor blade. They would cut like crazy, but haven't any strength and are guaranteed to chip.

This steel will rust, virtually while you are watching. Always keep a light film of oil on the metal when it is not being worked. Add baking soda to the rinse water when you're polishing to help avoid rusting. The off side will rust while you're polishing the other side. Make sure they are well oiled before wrapping them in anything.

Do not heat the blade beyond 400 degrees F. That could anneal the hard edge. If this should happen, the blade may be rehardened. All you have to do is send it back and beg Bob's forgiveness. It will have a bit more curve if it has to be re-hardened. This isn't a traditional polishing method for the Japanese style, hard edged blade. The traditional method would take well over forty hours for an eight inch blade. This style polishing can be done in three and still look good.

Your YAKIBA blade is ground to about 220 grit on the Burr King, and that's about the grit size you should use to start with hand rubbing. Use wet or dry paper and a relatively narrow rubbing block. I personally like to use the sequence 180, 280, 400 and 600 grit. Full directions for hand rubbing are found in another section of the catalog. If you want to use stones, find a really coarse one and it'll get rid of the grinding lines very quickly. Stones are much faster for the initial smoothing steps. There's a section on that towards the back of the catalog.

Always work with the cutting edge away from you, unless you enjoy having stitches put in. You have to roll the blade or the sanding block a bit to form the cutting edge properly.

Stop in the rubbing sequence after 400 grit, perform all of the guard and sheath fitting, then go on to hand rub the 600 grit. The blade collects a number of marks when handling and they're easier to remove if you don't have to do the 600 grit over again.

The actual temper line will be slightly visible throughout the whole process, and clearly seen at the 600 grit rubbing stage, but the next step will bring it out in bold contrast. You etch the blade gently with a slightly contaminated solution of weak acid. That's a lot of words to describe a bath of hot, apple cider vinegar. We found the "Heintz" brand to work best.

If possible, immerse the whole blade in a heated bath of vinegar, ( about 120 F) leaving it in until the cutting edge turns brown or black. The mild acid attacks the crystalline structure of the hardened steel much more aggressively then the soft parts. This brings out the "frosty" looking surface that you're after. (The first immersion in the bath of weak acid won't have much of an effect, but the next three or four will do a lot more.)

Pull the blade out of the bath, clamp it as you would for hand rubbing, and then polish off the discolored surface by rubbing with a mixture of pumice and water. Again, you won't see much happening at first, but quite a bit as you go through the process several more times. Rub with a paddle of inch square (cross section) wood, about ten inches long, with a pad of heavy leather glued along the last four inches on one side. The leather will shape to the blade and help hold the pumice you're using.

Go back to the acid bath, repeating the etch and pumice rubbing step until the division between the two areas of hardness is at the degree of contrast that you would like. You could make it very subtle, or outright bold, depending on how you prefer to have the final product look. Each "round" of etching will make the division line deeper in color, and the edge slightly more "frosty" looking. This can be overdone, so try not to go beyond half a dozen cycles.

If the blade is long, and getting it immersed in a hot vinegar bath will be a problem, you might try using ferric chloride as an etching agent, at a diluted strength of up to one part water to one part ferric chloride. Radio Shack carries it as "Etchant" for circuit boards. Put about two quarts, (one water and one of ferric chloride) in an inexpensive wallpaper tray. Hold the blade horizontally above it, and brush the ferric chloride onto the metal with a new 2" paintbrush. Do both sides, flipping back and forth, and stop after about a minute and a half. Rinse the blade with a baking soda solution to stop the acid. Do not get the ferric chloride on your hands. (If you get the tip higher than the tang, you'll end up with Ferric Chloride on your hand. Wash immediately, and use baking soda to keep from getting blisters. The color wears off in about a week.) Ferric chloride is a milder acid that doesn't attack skin and immediately burn like some of the nastier acids, but can still raise a blister if left on for more than a minute or two. In cooler weather, warm the tray in the sun for awhile to make the acid cut better.

If the temper line is accented enough, you're done etching. If not, give the blade another minute or two of etching. It is much better to use ferric chloride with very short periods of etching, about a minute, wiping off the black residue between applications. If you leave the blade in too long, the build up of residue inhibits the etching action on the hard metal, but it keeps on with the soft metal, sort of averaging everything out, which is just the opposite of what you want. Ferric chloride should be diluted with mineral free water, up to 50 - 50. Using it "straight" will have it etching the soft parts about equal to the hard parts, which isn't what you need to bring out the temper line.

Ferric chloride may not be as nasty as some of the other acids, but still needs to be handled carefully. It won't eat holes in your clothes, but will stain them badly.

Now, after etching, the soft part of the blade will need a bit of brightening up to make it look right. We've tried a number of compounds that work. One might use tin oxide lapidary polish, aluminum oxide, cerium oxide or even red iron oxide. The aluminum oxide seems to cut fastest. 1200 grit, commercial lapping compound works great! Even rubbing compound from the local body shop will work. Apply the compound, which is usually bought in the powder form, with water and rub briskly, using a leather pad on a paddle as you did with the pumice, but not the same one. Flitz or Simichrome will do a good job too. You want the soft part of the blade to take on a pretty good shine, with sort of a pearly glow. Don't try buffing. That would wipe out all of the etching in just a moment.

There is a lot of latitude in the appearance of the temper line. Some prefer a really bold line, visible from halfway across a showroom. Others want a subtle line, more in line with the ancient methods of polishing. Either is possible with our blades. You have the choice of virtually any appearance that you would like.

The spine of the blade should be rubbed to a mirror finish, using 1000, 1500 or 2000 grit paper that can be found under abrasive in the catalog. If you have a sword or blade with a grind line, everything above the grind lines should be brightly polished to 2000 grit. Ancient blades were polished, then burnished to a mirror finish in these areas. Burnishing is not that difficult. You may make the tool from an ordinary drill bit, the chuck end, and rub to an extraordinary polish. Call for details on this. The catalog is getting too long.

Once you have polished one of these blades, you'll never be fooled by a fake temper line again. The surface and effect are quite unique.

If you run into a problem and need some help, call Bob at the shop between 5 and 7 pm, Pacific time. 818/956-5110.

If you're interested in trying to do the selective hardening yourself, the best clay that I've found to date is from the A. P. Green Co., a refractories manufacture with distributors nationwide. It's called #36, high alumina, refractory cement. Cost is under a dollar a pound. It comes in 50 or 100 pound pails, already mixed and ready to use.

A word of caution. Any blade can be broken, no matter if the back is soft or hard. Metal may have flaws, or the idiot factor may have simply taken over. Japanese blades do not have the springy qualities of European swords. They bend, easily. People often try to do really dumb things with swords. It's part of the masculine thing.

If you hit hard against something that has a lot of resistance, the blade will get a little hump in the back, opposite the point of impact. When the blade hits while tipped to the side, it will bend to the side. I have nightmares about a blade loosening in a handle, sailing into a crowd of spectators.

The fact these blades are a fair copy of an ancient Japanese sword has absolutely no magical effect. In fact, it almost invites accidents when people try things that they should know are wrong. Please, don't let me hear that you've had a serious accident with one of mine.

I had a guy spend some time at my counter one day, explaining how expert he was with the use of the Katana, or Japanese sword. He decided to show me the proper, chopping stroke, using one of my boldly curved, Tachi blades.. The ceiling was high enough, and there wasn't anyone else around, so I said he could demonstrate. This fellow tried an overhead stroke. With a tremendous yell, he swept the blade way back over his head in the backstroke.

Then he let out another, different sort of yell. He'd wound up so far on the backstroke that the tip of the blade went about an inch and a half into the top of his right bun. Never did come back to show me how the rest of it went.

Moral of the yarn. Anyone can do some Errol Flynn stuff with a button tipped foil, but when you're messing around with two and a half feet of sharp steel, you'd better know where it is, all the time.


Not too long ago, at the San Jose Knife Show, a visitor remarked on how interesting it was that a hotel would invite us exhibitors in for the weekend, at the hotels' expense.

Ole' buddy Sornberger said that if he won a million in the lottery, he'd probably keep on making knives until it was all gone.

Do not heat the blade beyond 400 degrees F. That could anneal the hard edge. If this should happen, the blade may be rehardened. All you have to do is send it back and beg Bob's forgiveness.

Always work with the cutting edge away from you, unless you enjoy having stitches put in.

Never grind after a meal that includes broccoli, cabbage or Brussel sprouts. One burp inside the dust mask could have near fatal results.

A word of caution. Any blade can be broken, no matter if the back is soft or hard. Metal may have flaws, or the idiot factor may have simply taken over. Japanese blades do not have the springy qualities of European swords. They bend, easily. People often try to do really dumb things with swords. It's part of the masculine thing.

I have nightmares about a blade loosening in a handle, sailing into a crowd of spectators.

The fact these blades are a fair copy of an ancient Japanese sword has absolutely no magical effect. In fact, it almost invites accidents when people try things that they should know are wrong. Please, don't let me hear that you've had a serious accident with one of mine.

I had a guy spend some time at my counter one day, explaining how expert he was with the use of the Katana, or Japanese sword. He decided to show me the proper, chopping stroke, using one of my boldly curved, Tachi blades.. The ceiling was high enough, and there wasn't anyone else around, so I said he could demonstrate. This fellow tried an overhead stroke. With a tremendous yell, he swept the blade way back over his head in the backstroke. Then he let out another, different sort of yell. He'd wound up so far on the backstroke that the tip of the blade went about an inch and a half into the top of his right bun. Never did come back to show me how the rest of it went. Moral of the yarn. Anyone can do some Errol Flynn stuff with a button tipped foil, but when you're messing around with two and a half feet of sharp steel, you'd better know where it is, all the time.

BOOKSHELF

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