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A brief lecture on pattern welding and pattern development

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To understand the process of pattern development in PWS or mokume Gane, you must first think in terms of manipulations to the billet. (I'm doing this on my phone with only one finger, so this could take a while.)

Manipulations are ways to rearrange or deform the starting billet of material. The first manipulation is the original stack configuration. The last is always the grinding of the billit to final shape. In be tween these two, are the steps of pattern development. 

Original stack: Most folks start out with a simple stack of two different materials and alternate one after another.  Whether the two materials are the same thickness, affects the final pattern. Whether different thicknesses of the same materials in the same stack, just in different locations, affects the pattern as well. Let's say we are making a PWS. Billet from 1095 (A) and 15N20. (B) The simplest of stacks uses equal numbers of layers with each layer equal thickness. So, both materials are an 1/8" thick and we arrange a 10 layer stack as ABABABABAB. if our B material is thinner than our A material, and we do the same stack, our pattern will be different than the one where all layers are equal thickness.

Try to visualize the first option. Equal numer of layers, each the same thickness. Now slice a diagonal line through it. You just cut through a layer cake and each layer appears the same as those adjacent to it, only a different color. Do the same thing where the B material is thinner than the A material and the layer cake looks slightly different.

Playing with the starting stack and the thicknesses of materials and the locations of those materials changes the pattern.  If you still use only two materials, but you have some A that is 1/4" and some that is 1/8" and you have some B material that is 1/8" and some that is 1/16", how you arrange those layers in that stack affects the pattern when all is said and done.

The grind: The last manipulation is the grind. Whether that grind is flat, concave or convex (or changes along the length of the billet) changes the way the final pattern looks. How deep you grind also changes the pattern. Look at the post in Video and Mutimedia by Niels Provos for "Pattern Welding Explained". (It is pinned and for good reason) This shows how depth of grind through a simple single twist changes the pattern. https://www.bladesmithsforum.com/index.php?/topic/37018-pattern-welding-explained/

Intermediate manipulations: there are infinite manipulations and manipulation sequencing combinations to use in pattern development. Each one results in a different deformation of the billet. Each type of manipulation also can be done to varying degrees to make slight alterations to the pattern. To use an example, let's take a simple twist.  How tightly you twist that billet affects the pattern when you grind into it. How deep you grind also changes the final pattern.

See how quickly this can expand your options with minor manipulations?

The simplest manipulation we do is forging the billet. You might think that's not much of a deformation or manipulation, but let's consider what happens during forging. 

A hammer strikes a single spot in the billet and leaves a small dent or crater. It is deeper in the center than it is at the edges of the dent. So if I cut a cross section through the dent I would see a series of flat lines that gradually depressed and then gradually rose again to flat lines. Now repeat the hammering across the width and length of the billet. No two hammer blows are identical and most will overlap causing a multitude of dents in the surface, dents in the edges of other dents and dents in the edges of dents on dents, etc. The random denting causes the layer cake to compress in various locations to various depths. The resulting pattern when ground down can be quite stunning.

Types of manipulations: The most commonly used is probably the twist. There is drilling holes. Drill through a few layers in random locations and forge down so the bottom of the hole comes up to meet the top. The result is called either bird's eye or pool & eye. It's a bunch of little bullseye's in the surface.  There's crushing, which is forging the edges down rather than the faces. This is also done by "forging on the bias" or truncating the corners of the billet to resquare it. Think tipping the billet so a corner is up and hammering it down. Repeat on all four corners until it is square again. Gary Mulkey does this in several of his posts so look for his WIP threads. They are excellent photographic records of pattern manipulation. The list of manipulation types is much longer and you are only limited by your imagination and willingness to add "one more manipulation".

Stacking or sequencing manipulations: This is using different manipulations in a sequence. So let's talk about twisting and forging. If you twist first and forge second, you will get a very different pattern than if you forge all those dents in and then twist. The pattern will look vastly different if you crush first and then twist and then tile cut. ( I didn't cover tile cutting did I? Well check out Gary's threads for how that's done)

So how does one determine what sequence to use to get a desired effect?  Well, this takes two things: the ability to think backwards and the experience learned from experimentation. 

So make a billet and give it a go. Or, buy a bunch of modeling clay or plasticine and start experimenting with manipulations and grinding ( just take a knife and cut through the clay) Owen Bush does a fantastic video of this in the Arctic Fire 2016 videos. Go check it out: https://www.bladesmithsforum.com/index.php?/topic/37647-arctic-fire-2016-videos/


Edited by Joshua States
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Thank you the text was enlightening. Now to read the references you cited.

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Part 2 of the lecture series. 

I still only have my phone, so the visual aids are a little rough.

Types of patterns. I break the different patterns into two families: Face grain patterns and End grain patterns. These refer to the position on the billet where the pattern is developed. 


I can't think of any patterns that develop on the edges, except those that end up with edges the same as faces (like a twist) or ones where the edges are changed to ends (like feather) bit more on that later.

For now let's talk developing face grain patterns. We already discussed the random pattern and touched on the pool & eye. One more bit about P&E pattern. It can be achieved two ways: drilling holes and flattening the bar or pressing divots into the faces and grinding the bar down. I prefer starting very thick, drilling and forging down, drilling again and forging down and repeating until the desired thickness is reached.

Ladder patterns. This is a classic and ancient pattern. Like P&E, it can be achieved two ways, each of which has variations. So there are many different looks to a ladder pattern.  Basically, it is developing a series of grooves across the faces, offset from one another and flattening the bar. You can press in the grooves and grind down, or you can cut the grooves and forge flat. The grooves can be wide or narrow, deep or shallow, close together or spaced apart, rounded or V shaped. All these things affect the topography of the final image in the pattern.


Twist Patterns. The twist is also an ancient pattern. The bar is drawn out to a long square bar and twisted. Some people grind the corners off before twisting some twist square, some forge the bar into a long round before twisting. Tight twist or loose twist, different looks happen.  All these things change the topography in the pattern. Twists are often made with small cross section bars (3/8" to 3/4") and stacked side by side or in a bundle and forge welded back together to make a bar big enough to create the finished product. Alternating direction of twisted bars next to each other is commonly called a Turkish Twist pattern. Cutting a twist length wise in half and flipping it "inside out" yeilds an interesting look.

Sgian Dubh_20180828181601720.jpg

Cutting it in four pieces lengthwise and flipping all 4 pieces inside out is one version of explosion pattern. ( Sorry, no pics of that. Use your imagination)

End Grain patterns. These have become quite popular in the last few years with mosaics and W-pattern variations. I also include "canned patterns" in the end grain family. These are stacking various items like small billets, round rods, square rods, foil sheets, etc inside a square tube and filling the voids with powered steel. Weld it solid and cut off the can. You now have a solid bar with the pattern in the end grain.

To visualize this best, let's start with the W-pattern.

W-pattern diagram.pdf

What happens here is the end looks like a bunch of W's in rows of varying sizes facing each other open end to open end and point to point. You can get the end pattern on to the face by tile cutting (see Gary Mulkey threads) or by accordion cutting.


This is very similar to what  you do in ladder pattern. Changing the depth and angles of the cuts drastically changes the topography of the pattern 

More later. My hands are tired.

Edited by Joshua States
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Joshua asked me to post this in this thread so here goes.
Just the spec.
This is a 340 layer random billet of high M 1075 and 15n20
Pattern is created by grinding into the final billet several times in the reduction process.
So once when the billet has been final welded and then once at about half reduction.
I grind at angle to each other making various crosses and X's.
This is coffee etched at 500 grit polish.

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Thanks JJ! Really nice random pattern example.

I am hoping that more experienced makers will add examples and info as we progress. This can become a community effort at explaining and demonstrating different patterns.

Edited by Joshua States
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Got to thinkin,  (scary I know), but I haven't seen, or recall seeing any one do a raindrop pattern on a knife or sword

on this forum a, friend of mine showed me how he did  it a few years back, food fer thought.............;)

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I think that the cheap damascus from India kinda gave the raindrop pattern a bad name, as at least 50% of those knives have a raindrop pattern...

Here's my own take on a random pattern.  I used several different hammers to produce a bumpy forged surface to disrupt the layers, then ground to final cross-section...


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I have done a couple of dirks and a giant messer out of raindrop, made by the press-and-grind method before forging to shape to give some randomness to it.



sword point on polish.jpg

sword and me.jpg

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These are great examples of the raindrop and random patterns! Thanks guys.

I will post a couple of twist pattern examples.

First a better view of that little dagger with the inside-out twist.

Sgian Dubh v2.jpg

Now a simple fairly loose twist in a pseudo-Persian fighter style.

Persian (1).jpg

And lastly, a loose-twist Turkish Twist with 4 bars

Round 2 v2.jpg

Look really close and you can see the lines between the bars.

Round 2 (7)-opt.jpg


Edited by Joshua States
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  • 11 months later...

I just completed a Turkish Twist (see photo above) with 4 bars and thought I would post the process. It all starts with a normal billet of alternating steels that gets forge welded together.

1 Forging.JPG

This gets drawn out into thin bars anywhere from about 1/2" square to 3/4" square (or whatever you are comfortable twisting). I had enough steel to make two bars 5/8" square and 30"-35" long.

2 bars.JPG

You then need to create opposite twists in the bars. For this project, I only needed one of those bars, so I twisted half of it to the right and the other half to the left.

3 Half & Half.jpg

I then cut that into 4 pieces, two of them left twist and the other two right twist. I then flattened them back into (mostly) square shape.

4 bars.jpg

Grind the mating surfaces clean and parallel. If you have a work rest on your 2x72, make sure it is square to the platen. Keep the same side down when grinding opposing sides. This will make the two ground sides (mostly) parallel. 

5 clean bars.jpg

Stack the bars alternating the twists and tack weld or wire them them together.

6 stacked bars.jpg

Reweld the 4 bars to each other.

7 Final welds.jpg

When you are confident the welds have taken, hammer the faces flat again.

8 final.JPG

Now I have a 8" long bar that is 1-1/4" wide, and about 3/8" thick. It will take some serious grinding to flatten out and get enough depth for the Stars to come out in the top bar, but the bevels will expose the stars in the lower bars. I will probably forge in the tang, point, and the choil so that the bars follow the contours, but you can also just do stock removal. In the knife above, I did not forge the point. You can see the lower bars just disappear. I did forge the choil and you still see all 4 bars in the ricasso.

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You are welcome.  I had forgotten about this thread until you bumped it this morning, and then I realized it is full of the kind of info new makers of pattern-weld really want to know.  It needed pinning, in other words. B)

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  • 1 year later...

I just posted this image in a different thread, and checked to see if I ever put it here. I haven't yet, so here is my method for the W-Pattern. Pics will follow.

W-pattern diagram V3.jpg

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So this is a starting billet of 22 layers (1095 & 15N20). In this pic, it's about 1-3/4" square and 8" long.

I forged it down to approximately 1-1/2" square

1 Starting billet 22 layers.jpg


Here I am truncating the corners down.


2 Truncated corners.jpg


I did not take this all the way to square again. This time I left it a little more octagonal and started to flatten it down.

This is after 2 heats through the power hammer.


3 start to flatten.jpg


Eventually, I got it flattened out to somewhere around 2x16x5/8


4 Flat bar.jpg


Edited by Joshua States
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Cut this bar into roughly equal length pieces and grind the mating faces down in preparation for the restack weld.


5 Ground & Stacked.jpg


This gets welded and drawn out again. You can do this cut/stack/weld operation as many times as you like. The more times you do it, the finer the pattern development gets. Eventually, you finish stacking and draw out a bar about 1 inch square or so.

1 Annealed bar.JPG


Now I do the accordion cut. The side of the bar needs to be marked for the removal of wedges. I use some thin copper templates I made in various angles after spraying the side with blue layout fluid.


3 Templates.JPG


Scribe the template moving it along the bar, until the entire side is laid out. Then move the template to the opposite face and create the accordion marks.


4 Cuts marked.JPG


I cut these out using my porta bandsaw. This only works after doing a full spheroidal anneal on the bar. If you do not have a programmable oven, you will need to do this with an angle grinder/cutoff wheel, or just use the 2x72 and grind them into dust. Some guys, like Gary Mulkey, drill a small hole in the inside corner of the V to eliminate a stress riser. I like to keep my cutouts and weld them back together, I need that corner to be sharp, so I round it out afterwards.


5 cutting.JPG


Once I complete the stock removal, I have this bar. This gets cleaned up with the corner of the flat platen and forged down flat. 


6 New bar.JPG

Edited by Joshua States
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  • 7 months later...

Such artistic patterns...THIS is why blademaking is such a respected craft. Now that I see all these I am forced to lift my jaw from the floor.



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  • 5 months later...

I am working several projects at the same time, and today I got back in the shop to make some Billets and reduce a piece of a 1095 ingot down for some Damascus. I figured I would post some of the progress shots here. I will be doing a mosaic billet, a Ladder pattern, and either an explosion pattern or a feather. (I haven't really decided which). There is also a twisted bar for use in a dagger hilt. That project is a multi-bar blade made of 9 twisted bars.

Anyway, Here is how it begins. This is the starting pieces for the billets.

There is a bunch of 1/8" 1095, a slightly smaller amount of .06" 15N20, and some strips of .004" 201 Nickel.


1 Pieces.jpg


The pieces are arranged in some sort of pre-pattern. Some of the billets have a piece of 15N20 with 201Ni on either side, some do the same with the Ni and 1095, others have two pieces of 15N20 with two pieces of Ni, etc. The stacks are symmetrical from the center out to each side. One stack is much smaller than the other 3 because it will be used for the dagger fittings.


2 Stacks.jpg


These stacks get tack welded together and put on handles. Then they soak for a bit in diesel fuel.


3 Diesel soak.jpg


The forge on the left is the welding forge. The one on the right is just being used to cool the billets after they are welded together.


4 Cooking and cooling.jpg


After welding them up, and squaring to approximately 1-1/2" square. The smaller one is 1" square. This will be reduced to 3/4" square for twisting.

The 1095 reduction is about 1-1/8" square. (top center)


5 Welded billets.jpg


The tags from the stacks are transferred to the handles, so my tiny brain doesn't loose track of which is what.


6 Tagged handles.jpg


Edited by Joshua States
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