Gahagan,
Break the process down into "pieces".
Clay coating
Looks like everything is wide open concerning the clay coating used, sorta like everyone still gets from point A to point B regardless of whether they drive Ford, Dodge, or Chevy.:3:
For the first time doing this, your preference will most likely be determined by whatever is easiest for you to obtain.
If you decide to do more of this, you'll probably settle on a favorite.
Application
Franklin mentioned the hamon tutorial by Stephan Fowler, and I think that is an excellent primer for anyone new to this- the pictures allow you to see the work in progression.
If you haven't visited that thread yet, it is worth your time to check it out.
http://knifedogs.com/showthread.php?1710-Hamon-Tutorial-LOTS-of-pics
Something I believe is very important is to be sure that the
entire blade be covered. The area of the blade you desire to harden still needs an ultra-thin coating of clay.
On that note, I believe it well to consider Bubba-san's advice in post #4, in regards to applying the clay evenly on both sides of the blade. This is easy to do if you have a relatively simple, straight hamon. More complex pattern naturally makes this more difficult, but not impossible.
Quench medium
Water? Brine? Oil?
Yep, it's very confusing!:confused2:
I have only done 4 blades in this fashion, and all used a heated water quench. ("Heated" meaning hot water from the faucet.)
The second blade cracked on me, but I have to wonder how enlightened I would be if somebody like Kevin had access to the other three and "put 'em under the eye.":biggrin:
Nevertheless, the other three seem to have survived, but that just means I haven't done enough of them. With a water quench, the "masters" have at least 25% rejection rate, really "good" can expect at least a third or more, and newbies like us should not be surprised with even higher percentages of failure.
Point is, blades
will be lost with this method. That's the downside. The upside is that if everything else is right, this method produces stunning hamons.
There are many methods people utilize to avoid the cracking problem associated with water/brine quenches.
Obviously, the edge cannot be too thin.
Others have their beliefs on temperature of the quench medium.
A very popular "fix" is an interrupted quench. Example- "In for 3 seconds, out for three. Then back in for three, back out for three. Then back in and stay until blade cools to water temp."
Still others use a "combination" approach. Example- "In water for three seconds, then out and straight into heated oil for remainder."
I will attempt a brine (saltwater) quench with my next blade, but I think I will keep the brine at room temp.
For more information as to why, check out this discussion:
http://knifedogs.com/showthread.php?14403-Quenching
Please take note that my limited experience with this is based upon these blades not being for others; they were simply "learning exercises" for myself.
And that, to me at least, is what will probably be your biggest obstacle- you have a customer that wants it, but you have no experience doing it.
Considering all the factors involved, the oil quench is probably the way to go if you can wait for the oil to come in. (I have never heard of anything "custom" that did not require some period of waiting.)
Whichever method you choose, it's always a good idea to have "spares on standby".
One final note, as you have not mentioned the
type of blade you're trying to produce.
Kevin mentioned the
sori (curvature).
The blades subjected to a water or brine quench will have a pronounced curvature. If you water quench, but do not want this look, you will have to anticipate and adjust for this. From what I gather, most adjustment is done after HT, as there is no simple way to determine exactly how much sori will be obtained.
Conversely, if you're doing an oil quench, and you
do want sori, then you need to shape it into the blade.
Good Luck,
Rob