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Post by Deleted on Dec 10, 2009 21:46:52 GMT
How does one determine this number? I am speaking with regard to Japanese folded blades and the ubiquitous 'damascus' or pattern welded steel.
The question got prompted by the Scorpion Knives and Bows site, run by our own forumite, archerout - he has a heading that states 'Upgrade to 416 layers now' and I was wondering, how did he determine that?
How does it work for Japanese style blades?
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Post by Deleted on Dec 10, 2009 21:49:25 GMT
It's all in the exponents.
They take the pieces of steel and stack up five layers or whatever, then weld it. Five. Fold once, ten. Again, twenty. Three times, forty layers...and so on.
They count the layers in the initial stack, then double it for each time they fold.
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Post by Deleted on Dec 11, 2009 2:01:53 GMT
It's all in the exponents. They take the pieces of steel and stack up five layers or whatever, then weld it. Five. Fold once, ten. Again, twenty. Three times, forty layers...and so on. They count the layers in the initial stack, then double it for each time they fold. well said.
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Post by Deleted on Dec 11, 2009 2:29:07 GMT
It is important you don't mix up the amount of layers with how many times it's folded. You can only fold steel so many times before the layers become redundant as I understand it. Now I'm not 100% sure so maybe one of our erstwhile smiths can correct me but I believe if you fold steel too much you lose carbon which makes the blade no longer viable.
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Post by Deleted on Dec 11, 2009 7:29:08 GMT
It is important you don't mix up the amount of layers with how many times it's folded. You can only fold steel so many times before the layers become redundant as I understand it. Now I'm not 100% sure so maybe one of our erstwhile smiths can correct me but I believe if you fold steel too much you lose carbon which makes the blade no longer viable. This is what I heard as well, but I'm also not a smith. It's important to remember that doubling a number makes it bigger very quickly. For example, if you were to fold something over 32 times it would have over 4 billion layers. A blade can't have more layers than there are molecules in its thickness, so there comes a point where folding it stops making more layers since each is only one molecule thick. That's my understanding of it at least, but I think it's pretty accurate.
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Post by Deleted on Dec 11, 2009 13:42:49 GMT
It is important you don't mix up the amount of layers with how many times it's folded. You can only fold steel so many times before the layers become redundant as I understand it. Now I'm not 100% sure so maybe one of our erstwhile smiths can correct me but I believe if you fold steel too much you lose carbon which makes the blade no longer viable. Basically, you know the number of layers by keeping count of how many times you fold the metal and doing the math. It's simple multiplication, really. I don't recall the exact numbers involved but there is a limit to the number of desirable folds. I don't think it has to do with carbon, though: according to my teacher there is simply a point where you want to stop folding because otherwise you get so many layers your eyes can hardly discern them anymore, which sort of ruins the whole point. I think Asian style folding uses more layers then western ones, though, since western patternwelding is specifically done to achieve the "damascus look." Don't quote me on that, though.
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Post by Deleted on Dec 11, 2009 14:00:54 GMT
I'm pretty sure that I read somewhere that the reason the japanese folded their blades was out of necessity, because their steel was so crappy and low carbon content they folded the carbon into their swords through the layers. I think there is a limit to how many times you can fold a sword, just like there is a limit to how many times you can fold a piece of paper.
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Post by Deleted on Dec 11, 2009 14:10:18 GMT
No so much a limit as you can refold and draw the steel over and over. You do loose a fair amount of material with each welding heat and the billet gets smaller and smaller.
Japanese steel is more of a consolidating process rather then pattern welding (search the maker Jesus Hernandez and look at his site.)
Western work as we know it is about patterning in the steel. Search this forum for Matt Stagmers 1450+ layer dagger for an extreme version of this.
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Post by Deleted on Dec 11, 2009 14:12:30 GMT
doesn't western patternation occur by welding the billets together, then twisting them into screws then forging them into a blade?
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Post by Deleted on Dec 11, 2009 14:35:36 GMT
I'm pretty sure that I read somewhere that the reason the japanese folded their blades was out of necessity, because their steel was so crappy and low carbon content they folded the carbon into their swords through the layers. I think there is a limit to how many times you can fold a sword, just like there is a limit to how many times you can fold a piece of paper. I had heard the very same thing; my question was borne out of my own ignorance on the subject. I figured it was something like that and was thinking to myself how tedious that must be, to have to count the layers all the while making the sword. Thanks for the responses, all.
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Post by Deleted on Dec 12, 2009 1:04:34 GMT
Each weld, you lose carbon, so there is a limit there. Also like Kerry Mentioned, material loss from scale, so there is a limit there. The pattern also does get too fine to see, I saw some damascus by JD smith that was barely discernable by the naked eye, but seeable and with different distinct layers (silver/dark) with a jeweler's loupe.
The japanese did indeed fold they're steel to purify it, not spiritually, materials wise.
EP, it's not hard, you write down how many layers you start with, then just count how many folds you do then multiply.
Technically there is no limit, but due to the factors I stated above, you will eventually end up with a very small bar of very expensive mild steel.
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Post by Deleted on Dec 12, 2009 1:21:42 GMT
doesn't western patternation occur by welding the billets together, then twisting them into screws then forging them into a blade? that's what the vikings did... you put one layer with "too much" carbon, one with two little, weld two bars of these (each having several small bars of "too much"/"too little" carbon steel), twist them together, and hammer them into a blade.
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Post by Deleted on Dec 12, 2009 8:29:16 GMT
I think there is a limit to how many times you can fold a sword, just like there is a limit to how many times you can fold a piece of paper. Not really a good anology, I think. Paper doesn't morph or melt as you are folding it. The closest non-metal material to steel I know of is actually wax. doesn't western patternation occur by welding the billets together, then twisting them into screws then forging them into a blade? There are many, many types of pattern welding. Type "mosaic damascus" or "explosion damascus" into Google prepare to have your mind blown.
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Post by Deleted on Dec 12, 2009 9:12:45 GMT
I think there is a limit to how many times you can fold a sword, just like there is a limit to how many times you can fold a piece of paper. Not really a good anology, I think. Paper doesn't morph or melt as you are folding it. The closest non-metal material to steel I know of is actually wax. doesn't western patternation occur by welding the billets together, then twisting them into screws then forging them into a blade? There are many, many types of pattern welding. Type "mosaic damascus" or "explosion damascus" into Google prepare to have your mind blown.Alright, my mind has been blown. You better clean up the brain splatter since it's your fault.
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Post by Matt993f.o.d on Dec 12, 2009 11:31:24 GMT
When you fold a bar over surely the bottom layer at the base of the fold actually gets doubled over, so when folding, the formula is actually more like X2-1
The only way to actually double the layers each time you weld is to cut the bar in half and stack it on top of itself. That way two layers would double to four, four to eight etc.
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Post by Matthew Stagmer on Dec 12, 2009 11:36:08 GMT
The loss of carbon has to do with how many times you heat it not how many times you fold. There are ways of adding carbon back in aswell. So tech you could fold a piece 1,000,000,000 times or more if you wanted to.
The paper fold thing doesn't work here becuase when you fold steel you then forge it back out a ways and fold again. With paper there is no re-shaping or drawing back out. Did that make sence?
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Post by Matthew Stagmer on Dec 12, 2009 11:39:01 GMT
When you fold a bar over surely the bottom layer at the base of the fold actually gets doubled over, so when folding, the formula is actually more like X2-1 The only way to actually double the layers each time you weld is to cut the bar in half and stack it on top of itself. That way two layers would double to four, four to eight etc. ehhhh. I mean thats taking it a bit far. The layers still end up one on the bottem and one on top so its still the same as restacking. I prefer to restack for one reason and that is to save material. I also often draw the bar way out after each weld and often stack 3 high. So the math can change when stacking but folding is easy math.
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Post by Dan Davis on Dec 12, 2009 12:42:43 GMT
When you fold a bar over surely the bottom layer at the base of the fold actually gets doubled over, so when folding, the formula is actually more like X2-1 The only way to actually double the layers each time you weld is to cut the bar in half and stack it on top of itself. That way two layers would double to four, four to eight etc. Nope, it still gets doubled. In the case of alloy banding you end up with two pieces of the same material next to each other, but it is still two distinct layers that get welded together.
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Post by Deleted on Dec 12, 2009 13:01:45 GMT
Matt: yep that makes sense. I guess I was talking out my arse somewhat not being a smith, it sort of made sense but I didn't take into account the fact that steel can regenerate itself, in that you can add carbon back into it and such.
Heres another question, is pattern welding these days purely aesthetic or can it serve a real purpose?
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Post by Matthew Stagmer on Dec 12, 2009 14:14:27 GMT
It can serve a purpose. For example say the only material that you have to work with was mild sheet and reallllly high carbon sheet yet you needed to make a durable blade. Make a stack of the two materials and the carbon can migrate and produce a blade that has a carbon level somewhere in the middle...other then that type of thing I am not sure that there is a modern day use other then looks.
Saying this, I am sure someone will correct me.
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