There are a variety of patterns in damascus steel-making, each of which represents a different way of laying up the bars, and manipulating them afterward. Each step brings with it a unique opportunity to fail: if you work too slowly, things may oxidize and not weld cleanly anymore. If you work too fast, you may wind up with inclusions or a mis-aligned weld. Two bars the have been forge-welded together are now one bar; you can’t re-position things.
My favorite, right now, is called “feather”:
That’s a superb example of someone else’s featherwork. Mine’s not anything like that; which means I have lots of headspace for improvement!
It’s made by making a stack of contrasting bars (usually 1095 and 15n20) then welding them, twisting them, and chopping them down the middle with some kind of cutter, then welding them back together mostly along the original line. Sounds easy, but it’s not! Normally, when you hot-cut the metal you’d be able to frantically brush the scale off and pour flux on, but this is a great big crack, you can’t get there from here.
I’ve made 3 attempts, so far, and I’m getting closer with each one. My first attempt came out looking like this: [Spoiler below the picture. You may wish to amuse yourself by looking at the picture and figuring out what I did wrong]
There are a couple of problems with that block. First off, it’s too little! By the time I draw that out into a knife-shaped thing, the pattern will be completely crushed. Second, some doofus (I am not going to name names!) cut it on the wrong axis. When the damn thing is glowing orange, you can’t tell where the pattern is, unless you had the presence of mind to carve a mark into it before you get started. This is how I learn things.
That little chunk wound up having a different purpose, which I’ll be writing about soonish.
Part of the problem is that, to get those lovely layers, you need to make a largeish block and ruthlessly smash it down over and over until they get thinner. Each “smash it down” ends with being formed into a square bar, chop-sawed to pieces, welded together on the cut-lines, and re forge-welded. Chop-sawing it or bandsawing it makes a mess of the surfaces, so you need to clean them up with a grinder so they will weld properly. If you look at the example bar I have at the top, you can see where the maker welded two chunks into the “stack.”
Since you want the feathering to run the length of the blade, that means you want the cut side to be the long side.
Hahahahahaaha! Joke’s on you, amateur!
There are many hobbies where the process’ difficulty scales with the size of the work-piece’s surface area. I used to do life-casting and I discovered that a 4″x4″ cast is easy, but a 24″x24″ cast takes 2-3 hours. A full-body cast requires 3 assistants, or it’d take 8 hours. Forging has some of those properties: the difficulty of working with a piece shoots up quickly as the piece gets bigger, because you eventually need a 50 ton press and a gigantic oxygen-free forge, and then you realize you need a forklift to move your billet.
After some thinking, I decided to do a simple stack, and not cut/weld like you are supposed to. There’s a value in doing things the way you are supposed to do them. This is how I learn things.
Now that’s a mighty block! It’s about 6″ on the “tall” side (which will get cut) and I made it non-square so I could tell the right axis to cut on. The chunks are surface-ground and compressed, WD40’d to help keep them from corroding, and welded. Some smiths take a block like that and store it in a bucket of kerosene to keep it from oxidizing – make sure the welds have cooled down before you drop a thermal mass like that in a bucket of kerosene, OK? [No, I did not learn that the hard way] [If you squirt it with WD40 and it bursts into WD-steam, it is too hot to handle] Here is another thing I learned: it’s easier to surface grind the bars before they are cut up. That went very prettily, and the bandsaw made background noises for an hour, and I had a 16″ tall stack of 3″x3″ chunks of steel. Next time I want a big chunk like this, I’ll just pull them out of the box, unwrap the butchers’ paper, and make a stack. This is how I learn things.
I also learned to label the things. One block of welded oxidized stuff covered in scale looks pretty much like another.
Sometimes, learning is also a process of violently remembering things we already know.
For example: steel expands when it is heated.
If you forget that, you may wind up with a glowing hot 15-lb block of steel, stuck in the mouth of your forge. If it’s just big enough to fit in, it’s not big enough to pull out. Here’s what I did, I turned the gas down a bit and let the part of the brick that was stuck cool down and wiggled the whole thing a bit until the weld on the handle broke off.
When I said earlier that the process gets harder as the work-piece scales up, this is part of what I was talking about. Instead of having that nice handle, I was now down to using tongs – and tongs, on a billet that large and heavy, are an awkward two-handed process that feels a lot like some kind of satanic gym equipment: “Press together the handles of The Torso Torsioner of Torment, while I sit and sip a mint julep and laugh at you, mortal!”
Once I got it out, I put it on the anvil for some furious whanging to even that top-edge out so it would slide awkwardly in and out. That let me get some flux on it and give it a few taps to start the layers of steel sticking to each other. By now I am about 2 hours into a process that I expected would take half an hour. Every single bit of it is harder – now, I have to plan carefully how I put the brick back into the forge, so I can get the jaws of my tongs around it; I have to think about how I’m going to pull it out and rotate it (if necessary) without putting it on the anvil, which will suck heat out of it. It’s kind of like a game of Tetris except horrible when you lose.
Do this as an experiment: put your hands in front of you about a foot apart, turned like they are holding the handles of a pair of great big air-tongs(tm). Now, imagine you have a 15-lb yellow-hot weight at the end. Still with me? Next, imagine you have a forging press next to you, 3 feet away. Your mission is to figure out how to turn your arms with those tongs, so that you neatly and safely place that mass in the jaws of your forging press without dropping it on your foot.
The whole time, the forging press is watching you with a strange expression on its face, its jaws gaping like this:
The press has interchangeable dies – contact surfaces – so to set the weld, I start with a big flat one that just straight squishes the metal together. That seems to work pretty well, but I’m worried that if the welds haven’t fully set, the block will burst apart when the time comes to chop it. Getting the whole block welded together is a lot of work; as the block gets bigger the thermal mass goes up, so it takes longer to soak in the heat before I can pull it out and squish it again. The good news (such as there is) is that it stays hot longer so I have more time to work with it on the press. Eventually it’s time to try the cut.
The cutter is a log-splitting wedge welded to a plate of S7 steel. I need to be careful not to squish it all the way through because I do not want the wedge to snap and shoot red hot pieces of wedge around the place. After my first attempt, I learned that sometimes the wedge will stick in the steel being split, which means I have to simultaneously grab the block and hit it with a hammer. Hard, with a hammer.
Between the bottom of the wedge and the lower die-plate is about 6″. The block I am working with is about 6 1/2″ – in other words, it won’t fit. That’s what the funny shape on the back of a cross-peen hammer is for: fullering. “Fullering” is the process of making a groove in a piece of metal. I hammer frantically for a while until there is an approximately 1/2″ deep trench across the top of the block, at which point it fits under the cutter, and I get to see what 16 tons of hydraulic power does when it’s behind less than 1″ of surface area. Under that pressure, the block reacts as though it’s cheddar cheese; I have to whack it with my hammer to break things loose but once it starts to cut, it moves surprisingly easily. [There is a good look at my cross-peen hammer a few pictures down]
That part, I don’t have pictures of because my hands were busy.
After this stage, ensued an hour of hell. First, you get it back in the furnace – or try to – only to discover it does not fit at all, anymore. While it’s cooling, you have about a minute to use your hammer and that anvil to get that chunk back into a shape that is small enough to fit in the door. Such an adventure we are having! At least it’s not freezing cold, like it is outside.
Trying to weld the pieces back together is hard. It doesn’t want to stick and there’s a lot of thermal mass sucking up heat. Each attempt to squish it back together results in something popping apart; a few of the welds on the side turn out not to be very good and begin to separate. Panic starts to set in.
Then, my hands slip with the tongs and the whole thing falls – kerplunk – into the sand tray. Now it has sand in the gap. It’s not going to weld with sand in there and I don’t want it to. I am done for the day. However, having learned from before I heat it back up and put it in the annealing bin to cool overnight – I don’t want it to harden or I will have a hell of a time doing anything with it.
Based on feedback from the Commentariat(tm) and elsewhere, I replaced the vermiculite in my annealing bin with pearlite. It turns out that not only does pearlite smell better, it’s an incredible insulator. I know this because 2 hours later I check up on the block and it’s still cheerfully glowing orange at me. Good grief. That’s just too big a chunk of metal to work with, with my existing gear and processes. This is how I learn things.
The next day I come back and use a cutoff wheel on an angle grinder, and complete the cut between the block. Now I have two blocks, which are a workable size. Those go back in the forge and are brought to welding temperature, formed up a bit better, and chopped and welded back together. The picture above is actually one of the halves of the larger block, being welded back together. Eventually, there are two differently-shaped blocks of steel, with who knows what inside of them.
Melted pearlite is sticky. I check with a file to make sure it’s annealed and isn’t hard, then put it on the bandsaw to knock off a slice.
I won’t be making any knives out of that. That crack is where the sides did not weld back together. My guess is that what happened is too much time being fiddled with allowed oxidation to happen in the split, and it didn’t re-weld.
That’s more like “zebra damascus” I’m afraid. To get the proper feathery look I would need to cut and stack several blocks like that, and that would absolutely require a taller press. The professionals who make this stuff do a set of stacks of bars, squish them and weld them, then clean them, stack the entire set, and squish and weld. This is a case of “nyaa nyaa nyaa look what I can do!” as far as I can tell.
The great thing about damasteel is that you can always find a use for it. Perhaps someone, someday, will say “I am desperately looking for material from which I can carve a steel zebra belt buckle” and I’ll be right there, the hero of the moment.
This is how I learn.
In the last picture, you can see some funny shiny inclusions on the edge and face of the block. Those are the welds that held the whole thing together. What I should have done is grind them out with an angle-grinder while the block was still hot (that gets very exciting!) rather than squish them into the block.
You can also see that two if the welds in the bottom block are split on the left side. It’s one heck of a paper-weight.
I keep trying to see a badger in those stripes. Damasteel badger belt buckles would make airport security oh, so happy.