Trying A San Mai Billet (WIP), Done

#6
I have always admired them, but after seeing that beauty in the custom knives section I have to give it a try.
Going to use 1084 sandwiched between 15n20. Hopefully it will go well.
Why not use mild steel on the outside and save your 15n20 for another project? A WIP would be great too.
 

DanF

Well-Known Member
#13
My last knives before the holiday are done, so I am starting to get things together to get started on this.
The center piece is 1084 (.126), and the outer layers will be 15n20 (.072). I have cut them 8.5" long and 1.5" wide. That should give me room to grind out any cold shuts/ occlusions from near the edges of the billet. I had other plans for the 1084 as you can see.
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Both sides ground down to clean, unmarked surfaces.
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Stacking and clamping the three pieces together to bring the four remaining sides to same size.
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Sides ground even, next time I will take the pieces apart and slightly chamfer all edges so no burrs will be holding steel off steel. I'll then clean it up good with denatured alcohol, restack, and spot weld the edges together.
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Weather forecast calling for cold, snotty weather tomorrow or next day so I may not get out to unheated shop for a bit.
 

DanF

Well-Known Member
#14
Awoke to 10* temps this a.m., didn't think I'd get any shop time in in that refrigerator of a shop. But, nature was kind to me and we hit the mid-forties, so time to finish prepping it, then spot weld the edges all around.
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Wire brushed the slag off, time to heat things up.
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Love hearing that thing go whoomph!

I'm always amazed by how fast, hot, and economical to run this little forge is.
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(I think his big brother just to his left gets jealous).
I heat it up to just past orange, when it is starting to almost go white, but not quite, I start tap dancing the hammer all over it. When the steel starts to cool, heading back to a bright orange, I put it back in the forge. I work from one end to the other in a three or four inch long area at a time, always overlapping the last area worked. You know it is welding the pieces because you can "feel" it as you are tapping along. You don't want to hit as hard as you do when you are forging the knife shape.
Once I work down the entire length, I flip it end to end and start over, working the whole thing again. I do this three times.
If you have welded the whole thing, you can "feel" the billet getting "stiffer", one solid piece now (hard to put it into words).

At this point, I shut down the forge, let the billet cool to around 800-900* and let it sit in the cooling forge until around 400-500*.
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Then I remove from the forge, wire brush it, and let it sit overnight. Next time I will start forging the blade
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KenH

Well-Known Member
#15
Dan, thanks for writing up this WIP on San Mia - I've been wanting to try a piece myself. Your WIP is giving me courage to try it. This COLD weather (40s & 50s) we're having is a good time to run the forge.

Ken H<>
 

DanF

Well-Known Member
#20
Just beyond nonmagnetic. For my eyes, that is just past cherry red going dull orange, but that doesn't mean a lot because we all see temps differently, I think. I recently completed a forge with pid/thermocouple so I will be paying attention to actual temps in an attempt to have a way to double-check my ranges and be more accurate with what I do. Also, due to the high temps used for forge welding and then heating the steel repeatedly during the shaping/drawing process, I'll be taking the steel through a normalizing sequence to hopefully reduce some of the stresses the repeated heat-and-beats are introducing, and reduce the grain size of the steel at completion.
Disclaimer: This is my first attempt at San mai, take what I am saying with a grain (or spoonful), of salt. I have had some success with low-layer pattern welds with the techniques I am using for this, but this should only be viewed as a "maybe interesting", attempt at this point. Better, and more knowledgeable Smith's than I have tried and failed with their early attempts.
I absolutely do not mind a knowledgeable person giving correction wherever they see error, (wink wink, hint hint, nudge nudge).
 
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