The “Joys” of Pattern-Welded Steel

As I mentioned a few weeks ago, I took a class in what is known as “Pattern Welded Steel.” If the term doesn’t make sense to you, don’t worry, you might know it under it’s more popular term: Damascus.

So before I tell you about the class, I should tell you about the material. Don’t worry, I’m not about to get boring NPC Professor on you (although I could, I won’t; I promise!), but to better appreciate it, you should understand it.

See, what we call “Damascus” is really “Pattern Welded Steel.” I was told that as we don’t know how real Damascus steel was created (seriously, we don’t know), we instead resorted to a tactic that at least denotes the appearance of it. That tactic involves taking a number of different steels, with at least some of them having a high nickel content, and welding them together.

No, I don’t mean with a torch, but with a forge. We almost melt them all together and form them into one bar, which is pretty crazy.

Granted, we do start by welding them together for the first step, but some people tie them with wire instead!
Granted, we do start by welding them together for the first step, but some people tie them with wire instead!

So when I say that it took me five days to make less than two feet of usable steel, you should understand the sort of work that went into this.

Unlike the sword class, I don’t plan on making this span over multiple posts. I think doing so would be horribly boring for you as a reader. You see, unlike the sword class, you don’t get many obvious changes to the metal.

This week, I literally started off with six pieces of metal, each one about four inches long. The pieces were of a mild, low-carbon steel, a section of a jackhammer, and bits of a band saw.

Our steels: jackhammer blade, mill saw blade, and a general mild steel.
Our steels: jackhammer blade, mill saw blade, and a general mild steel.

These were then stacked up, welded to a bar, and heated up. After heating to a certain temperature, they were coated with flux (an agent to help them bind together), then heated to almost the melting point before being clubbed by my hammer. Repeat until it’s solid.

Heat it then beat it! Not quite at welding temps, but getting there!
Heat it then beat it!
Not quite at welding temps, but getting there!

Afterward, you continue to hammer the bar into whatever shape you plan on working with for this process (normally a bar, but I’ve seen blocks), which brings you to to the next step: adding more layers.

Marked with some minor cuts to note where it's going to fold/be cut.
Marked with some minor cuts to note where it’s going to fold/be cut.

You see, that pattern you get in Damascus is caused by the number of “layers” in the material. If you take that first bar I made and left it there, we’d only have six layers, which is rather boring. Instead of stopping, you need to either fold the material (like the Japanese used to do with their katana), or cut the material into sections, stack them, then weld the ends/tie them together with wire before throwing it back into the fire.

Measuring the thickness of the billet before deciding on folding it or not. Marking an anvil with the thickness needed is brilliant.
Measuring the thickness of the billet before deciding on folding it or not.
Marking an anvil with the thickness needed is brilliant.

You then repeat the same process until you get the desired number of layers. It’s usually suggested to not go higher than a thousand layers, as the pattern gets too lost, but you don’t want to go below sixty (unless you are doing something special), as that’s too boring.

There’s also the issue of constantly fluxing the material, just in case of a bad weld or a possible opening somewhere. I probably used much more flux than I expect; I may need multiple boxes when I decide to do this at home.

ALL THE FLUX!
ALL THE FLUX!

I literally spent the first three days working on a single billet due to problems with the forge and fighting for the power hammer. Yes, my old frenemy was back again, as if I did this whole thing by hand, I wouldn’t have even finished the first one.

Fighting the power hammer. . .LIKE A BOSS!
Fighting the power hammer. . .LIKE A BOSS!

One of the cool things I learned about Damascus: you have control over the pattern. If you just leave it, you get the basic, random wavy pattern that you normally expect from Damascus, but if you take a round pattern, hammer it in, and grind a bit off of the top, you get this really nice wood pattern. You can do other things, like randomly grinding bits off, twisting the metal, or taking one patterned billet and welding it to another for even more pattern shenanigans!

There’s plenty to do here, but I’m sure you’re curious what I did and how it panned out. Well, here’s the scoop!

I had a number of problems with the forge; it wouldn’t reach the necessary welding temperature all the time, but I still worked at it. Eventually, I finished the first billet and got started on the second.

The casualty of the weekend.
The casualty of the weekend. Forge welding is dangerous work.

You see, while the class was “Pattern Welded Steel for Knives,” I was told that we would not be able to heat treat our knives; a heat treat is one of the key things that separates a knife from a knife-shaped object. Since treating Damascus is a different process, I was hoping I could work on it there, but with the note that we couldn’t finish the blade, I went right for making a second billet.

It was sometime on Day 3 when I was told we would actually be able to heat treat a knife, so once the second billet was on the final fold, it was time to rock out a knife.

Instead of my usual “big bad knife” approach I’ve done before, I wanted to do something different. Thanks to my badass boots, I decided to make a boot knife, expecting it to be relatively easy to not make too thin and not taking up too much of what little metal I had.

Oh, how wrong I was. At least on the easy part.

What I didn’t realize when making the billet was this: my welds weren’t perfect, and my welding with the MIG was probably too sloppy to get even welds (and overlapping material due to incorrect lengths probably didn’t help). It’s not something you can notice unless you have x-ray vision and, sadly, I’m not gifted with such an ability. Sadly, the only way to know if the weld took is to actually try to work with the material.

As you can tell, my welds aren't the best. This was round four or five with the welder.
As you can tell, my welds aren’t the best. This was round four or five with the welder. This may have been part of my problem.

Hammering out the blade portion was no problem; I did a slight variant of what was taught in this class and made a simple curve for my thumb. Then I got to work on narrowing the handle.

Just about done with the blade.
Just about done with the blade.

Once I started, disaster struck: the metal started to split. After a few attempts of trying to fix it while it was all together, I gave up, cut the knife off, and decided to attempt to fix it via working on a smaller surface area.

20150802_152740
And this is what a split can start off as. See that little spot on the bottom?
This is what it can look like after you cut things apart.
This is what it can look like after you cut things apart. Not much to salvage there, sadly.

The gamble thankfully paid off; thanks to a smaller area that I could heat properly, I was able to fix the weld on the handle without losing too much more of the blade. I welded the last of the billet together, and removed it from the defective part of the bar, leaving me about one inch of material left.

Like every other art form, giving something a shape just isn’t enough. This is just the first step, and the finishing process takes up the rest. My instructor commented that it can take him up to thirty-five hours to make a knife, especially one of Damascus, and I can now see why.

Post-annealing. This was four hours after the knife was made.
Post-annealing. This was four hours after the knife was made. The little block is all that’s left from the billet beyond the knife.

Once the knife is formed and annealed (a process that takes four to eight hours depending on the size of the knife), cleaning begins. First wave is with an angle grinder to get rid of the worst of the garbage. This step is also useful if you want or need to change the shape of the project; in my case, I cleaned up the edge on the handle and fixed one of the sharp angles in the thumb groove. I also took my last inch of the billet and ground it into a pair of rough looking coins.

After shaping with the grinder. The colors are due to heat, but it looks really cool.
After shaping with the grinder. The colors are due to heat, but it looks really cool.

This is also a golden opportunity to do any other work that may need to be done on the blade, such as drilling holes for handles. I used the opportunity to not only set the holes for handles, but to fix the curve of my thumb groove with a contact wheel. Usually important steps to do before you get too far with working, as once you heat treat, you can wreck your tools.

Next, it was to the power sander (in our case, an angle grinder with sanding wheel) to begin polishing. This thankfully doesn’t take too long, but sadly every step after this is done by hand, and they are incredibly time consuming.

Sand. Sand like your life depends on it!
Sand. Sand like your life depends on it!

Time and materials were limited in class, so we only did the base sanding at 220 grit (we should have started around an 80, but we used what we had), sanding away until we couldn’t see any of the marks from the power tools. Next up, we did the heat treat process by heating the edge to a near-critical temperature and the back of the blade slightly prior to quenching, cleaned the blade with 220 grit again (we needed a clean blade for the next step), and ended with the tempering process (heating to a certain color before quenching; thus the cleaning).

Immediately after quenching. You can see the pattern start to show in the blade edge here.
Immediately after quenching. You can see the wavy pattern start to show in the blade edge here.

This is the point at which I stopped on my knife and coins. By reaching this point, my blade and coins have been heat treated, have a nice protective oil coating, and just need some time with some sandpaper, an etchant, a bit of oil, and a sharpening stone. Even though my edge has what are called inclusions (minor cracks where the welds didn’t take), I was assured that they will not compromise the blade and, should they fall, a bit of sharpening will do the trick.

Heat treating is done. Now they get to sit until I decide to sand and etch them.
Heat treating is done. Now they get to sit until I decide to sand and etch them.

For those of you who are curious for the rest of the steps: after the blade has been treated, there’s a large amount of sanding time to go. I’ll need to start from 220 grit again, and after all of the deep scratches are clear, I’ll need to move to the next grit up. The suggested stopping point is between 600 and 1000 grit, and normally they are in intervals of 50-100. Once I hit that final 600-1000 range, things get pretty.

There’s a process of bringing out the patter we see in Damascus, and that’s etching. The chemical suggested is a diluted Ferric Chloride (a base, not an acid), which is the same as the etchant used in circuit boards. This causes oxidation and brings out the pattern caused by the welds (and is one of the reasons why we use nickel in Damascus).

The process for this step is a simple collection of soaking in the etchant, cleaning with water and pumice, and repeating the process. I’ve hear suggestions from simply soaking for three hours to checking it and cleaning every five minutes. I’ll be trying them out, so I’ll let you know what worked here.

As I wasn’t going to finish my knife (as we didn’t have the sandpaper), I went back to finishing my second billet.

The final fold!
The final fold!

That billet, of course, had it’s problems. While shaping the bar, I began to get what we call a “blister,” or a little bubble that shows up when things didn’t weld properly (or was too hot).

Do we have a pin I can use to pop this thing?
Do we have a pin I can use to pop this thing?

Thanks to a trick used by one of my classmates (hit it with a ball peen instead of a standard flat hammer) and a whole mess of flux, I was able to fix it to continue on and play with the pattern.

I mentioned before that you can control the pattern you get in Damascus by  tweaking what you do to the billet, whether it’s applying a texture tool, twisting, removing material, or even how hard (or evenly) you hit during the welding process.

I like waffles.
I like waffles.

With this in mind, as well as knowing the thinness of my material and my luck with the first weld, I decided to go with what we were calling the “Waffle Texture.” After folding my material one last time and (hopefully) welding it all together, I gave it the waffle treatment. Fun fact: once you apply a texture or do some removal, you’ll need to grind down some material to ensure you don’t have large pits. This is to ensure you don’t get a cold shut if the material folds to fill in the gap, and it also promotes the actual goal of your pattern in this process.

Cleaning the waffle.
Cleaning the waffle.

It wasn’t much longer to finish this billet. I had hours left, so I decided to stop pressing my luck and help clean up around the shop. Rather anticlimactic, but better than trying to start a project and messing it up due to rushing.

By the end of Day 5, I left with multiple notes, an understanding of how this material is made, a boot knife I need to finish, and a billet that may or may not be properly welded, waiting to be used on my next project.

And I had a good time with this crazy bunch!
And I had a good time with this crazy bunch!

What’s next? Honestly, that’s my last class for now, possibly for the year. This was the last class I could schedule for Peter’s Valley due to cost and vacation time. I might be able to do a hammer/axe class with my first instructor from the PA Renn Faire this winter if finances allow, but otherwise, it’s time to get my own tools in order and get my own forge fired up.

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