Hope this helps, Cameroo:
"How do you temper the blade?"There are so many variables involved in this process, most of which I'm not qualified to speak on. Assuming you've got a known steel and you're certain you've reached full hardness at quench (a whole other can of worms!), you can search the Internet for that particular steel's temper cycle. Assuming an unknown steel, or perhaps the possibility that you haven't quite reached full hardness, you can cycle up your tempering sessions as follows (which is what I do):
Bring your kitchen oven to 375 degrees F (really pretty cold for tempering, but at this point you don't want to overheat the steel just in case all didn't go quite right or you're unsure of the steel). Double check it with a second thermometer inside the oven, as most oven's thermostats aren't accurate enough. Mine is 25 degrees hot. Let the oven preheat for 20 minutes to achieve a nice consistent, even heat, then place your blade inside. You should do this immediately after you've quenched it and allowed it to cool (say 10 minutes or so). Otherwise, the internal stresses in the steel caused by the quench can cause it to crack. I like to temper for 1.5 hours, then shut the oven off and let it cool. Then I put a quick working edge on the knife and chop through a 2x4. If the blade still slices through a piece of paper afterward and the edge shows no signs of chipping, I stop and finish the blade out. A lot of folks recommend at least two tempering cycles, and I do think there is some benefit to it. You can research that point and make your own decision.
However, if the blade chips after the cutting test, it's still too hard for a serviceable cutting tool and I tempering it again, this time raising the temp in the oven 25 degrees. (Repeat 1.5-2 hours, shut the oven off, let it cool, chop test.) If it's still too hard, repeat the process again, raising the temp another 25 degrees.
If you haven't differentially heat treated your blade (i.e. you simply heated the entire blade and full-quenched it), then you should draw back the spine and tang a bit so that those parts are softer, and thus tougher, than the cutting edge. You can do this with a small torch, but there are some tricks to it (i.e. surface preparation, keeping the cutting edge submerged in water, gauging the temp reached via color, etc.). Do an internet search and you'll find some pros on that subject.
You referenced "the mud" having something to do with tempering. Well, you're 1/2 right
. The mud is actually furnace cement. You apply it to the blade in such a way that you insulate the back/spine of the blade while leaving the cutting edge (which is still at this point the thickness of a dime so that you don't damage the steel in the area). After thermal cycling (again, another ball of wax
) and bring to the proper heat for quench, you simply quench the entire blade. However, only the exposed cutting edge will cool fast enough to fully harden. The insulated back/spine will not, thus leaving it softer and tougher. The result, after proper temper, sanding/polishing, and etching, is the visible line call a "hamon."
"How do you etch your logo onto the blade?" I'll post a new thread on that momentarily.
"How do you make your mosaic inlay?"I buy little hobby pieces of brass and copper tubing (round, square, solid, etc.) at Ace Hardware and piece them together until they nest snugly. I then mix and color some simple epoxy with black acrylic paint and put it in a film container. I nest all the tubing, stick in into the epoxy, and then suck it up through the tubing using a syringe with a piece of rubber tubing attached. This goes over the end of the tubing and provides and airtight seal. I only do about 2" of tubing at a time to avoid getting air bubbles.
Hope this helps,
Regards,
Curt
