Quote:
Originally Posted by casimendocina
Boring questions but who is the report for and why do you have to write it?
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I just want to write it up for myself. Maybe post it to a blog I setup for smithing tales.
Quote:
Originally Posted by Sundae
Perry, pet, you lived in Newcastle.
You can take on the world.
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I just laughed out loud. It's true. Newcastle was a very special experience...
Quote:
Originally Posted by glatt
I'd like to hear more about the damascus steel. How it's done and why.
I see some sheets being spot welded, and then borax? being poured over the bunch and it being forged and pressed. And molten stuff dripping out. There are also the cross sections of the finished block, which look neat, but what do you do with that block to make a blade?
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Thanks for the questions. They give me a jumping off point to start telling the tale.
Damascus is a big topic fraught with controversy. We don't know the real process with which it was actually made. What we make today is similar in concept. Since that's what I know, that's what I'll describe.
The main reason modern knifemakers use Damascus is artistic. Collectors will simply pay more for a Damascus knife because of the way it looks and the mythology of the material. It does have a practical advantage in that you can combine the properties of two types of metal into one blade.
More technical, less loaded terms for Damascus are pattern welded or laminated steel.
When you are planning to build a billet of Damascus, you often choose to include a steel that excels at holding an edge and one that is resilient. The part that is magic to me is that at the end of the process of making the billet (which I'll describe later), you end up with the edge-holding steel along the blade edge and the resilient/springy steel backing that up to prevent breakage under heavy abuse.
Some time I'll describe the bladesmithing Journeyman trials and you'll understand why these properties are important and how they must be balanced.
Anyway, on to forging a Damascus billet. There are as many ways to do this as there are smiths. I'm just describing one of those.
The billet I'm going to describe is (as far as I can remember) made of 15N20 and 52100. You can see the actual properties of these steels
on Ed Caffrey's site. Ed is the guy forging this billet and is also the master smith who will be teaching me bladesmithing all of next week.
Thin strips of these two steels are welded together in alternating layers with the process most of you are familiar with.
This block of steel is then welded to a handle made of rebar or pipe.
The raw billet is then brought up to forge welding heat, which is around 2200 degrees Fahrenheit. It's then covered in flux (anhydrous borax, in this case). The flux helps prevent scale (impurities) from forming and being smashed into the billet while welding.
At this point the metal is about as hard as modelling clay. This soft glob of steel is then pressed in a large hydraulic press, which smashes the layers of steel together causing them to permanently and solidly weld together.
This billet is then reheated and pressed further down to a working size of about 1" x 1".
This square bar is then "re-squared." This is hard to describe. You basically press each corner so that the sides become the corners and the corners become the faces.
The welds are then ground out since they are junk and will interfere with the patterning.
That bar is then cut into several pieces and welded into another billet and then forge welded again.
Now you can see the pattern in the end of the bar.
The billet is accordion folded and flattened. This brings the pattern to the surface. Unfortunately I don't have a picture of this part.
The resulting bar is then forged down into rectangular bar stock. A common size is 1.5" x 0.25" x however long you want it to be.
That gets forged into a knife shape and then finished in a painstaking process I'll describe some other time.
