Jump to content

Damascus billet & metal stacking.


Recommended Posts

It doesn't make a difference. You're going to be twisting and stacking so you'll "lose" any outside quickly. Where this comes into play is with san-mai. Making that is like putting a hot dog in a bun. You'll have a marked difference between jacket and core with that. As for color, the high-carbon steel will be the one that darkens the most, while the nickel in the 15n20 helps it resist the corrosion process and stay shiny. Smiths try to keep the pattern of the billet in mind as the twist and re-stack in order to create designs such as W's, feather and ladders. Probably the easiest first designs are ladders and raindrop or trout pattern as many call it. With ladder pattern, once you've got your billet to the layer count you want, grind out grooves and then hammer it flat. Raindrop is about the same, except you use a drill to pock-mark the billet before flattening it.

Edited by Brian Myers
Link to post
Share on other sites

I like to keep the 15N20 on the outside. It doesn't pit as bad from the scale so when you try to clean it up to re-stack, you won't be grinding so much away. The 1095 will leave some deep pits that won't be in the 15N20.

Link to post
Share on other sites

It's not the number of layers so much as the relative thickness.  If you use thick 1095 and thin 15N20 you'll get a balanced dark-light look if you have a reasonable number of layers for the pattern at hand.  If your layers are the same thickness, the bright will overpower the dark and it'll be a mostly shiny blade.  Back in the 1980s when Damascus was becoming common, people used 1/4" thick 1095 and pure nickel foil, around 0.007" thick.  That thin layer of bright made for a blade that was mostly dark.  In the 1990s people discovered AISI A203E nickel steel.  It was used for pressure vessels and came in 1/16 to 1/4" thickness.  Mixing that with equal parts 1095 at 1/4" thickness made for a mostly bright blade.  In the late 90s into the early 2000s we played with L6 for the nickel layer, since it was high carbon as well.  But it doesn't play well with 1095, making for a difficult heat treat.  Then in the 2000s we discovered 15N20, which comes in fairly thin stock and acts just like 1095 in heat treatment.  Then 1084 made a re-appearance, and since it etches darker than 1095 due to the increased manganese, it became the alloy of choice for the dark layers. It comes in 1/4" thickness, and 15N20 comes in 0.065" and thinner.  If you stack that up and make a billet, it comes out just about perfect.  

 

The pattern you want has a great effect on how many layers you need.  A twist doesn't really care how thick each layer is, and can be nice with as few as five layers or as many as a few hundred.  Random doesn't do well until you get past 60 or so layers, up to around 300.  Ladders and raindrop look best to most people between 150 and 350 layers.  

 

The number of layers has a far more pronounced effect at low layer counts.  With a billet of 1084/15N20 seven layers thick forged down to blade size without any folding or surface manipulation will give a very high contrast blade of broad bright stripes and dark zones.  Take that up to 300 layers and it becomes almost uniform, with a much more subtle pattern.  This can be jazzed up by doing a high-contrast etch.  This is doing a deep etch to get topography

 followed by darkening the dark layers while polishing the bright.  This can be done by cold bluing, hot bluing (although that can screw up your tempering), or the latest version, the concentrated instant coffee etch.  These darken the 1095 or 1084 while not bothering the 15N20 much.  Then you polish the blade with a single thickness of the finest grit sandpaper you used prior to etching glued to a hard backer.  This polishes only the high spots (the bright 15N20) but can't get into the valleys (the 1095 or 1084). 

 

If you don't have a press or power hammer, twist patterns are your friend.  They can look great with the least amount of heavy forging.  

 

  • Like 1
  • Thanks 1
Link to post
Share on other sites

Alan covered it pretty well.  He did forget to add, however, that we love and want to see pics!;)

  • Like 1
Link to post
Share on other sites

Thank You all for the excellent information. You just rocked my tiny world!

 

If I asked for help a few years back Iam sure I would have had less disappointments. 

 

Attached is a photo of my first knife( or should I say letter opener)....Silver/Copper/Steel  

mokume gane knife 019.JPG

  • Like 1
Link to post
Share on other sites

saved that information @Alan Longmire for when I get to play with the helve hammer . Have a couple of tooling projects to finish (and show) before I get to some blade forging.

Edited by Garry Keown
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...