Copper and nickel San mai blade

[Paul Checa]

Hi guys, 

 

So the time has come to make a copper San mai blade. I was thinking of doing a nickel outer shell. Then copper, then hardenable steel core. 

 

I'm open to any and all tips, recommendations, warnings, step by step of how you would do it, and what you would stay away from.

anything else that will help me with this new goal. 

 

Thanks so much in advanced. 

 

 

[Gerhard Gerber]

Do a search on youtube for CuMai, I want to remember one or two channels had some good videos.

[Shane Atwood]

I have forged a couple cumai blades. Be super careful with temperature. Copper melts at 1984 deg.F I have melted the copper out of a blade or 2. Stack your billet up, outer layers, copper, then core and weld all the way around to seal it up. If you do over heat it the weld will help hold the molten copper in. My only concern with putting nickel on the outside is it is soft and scratches kinda easy. Maybe 15n20 and polish it after etch might work. Here is one I'm working on now. It was a Damascus jacket, copper, and 1084 core.

[Paul Checa]

13 minutes ago, Shane Atwood said:

I have forged a couple cumai blades. Be super careful with temperature. Copper melts at 1984 deg.F I have melted the copper out of a blade or 2. Stack your billet up, outer layers, copper, then core and weld all the way around to seal it up. If you do over heat it the weld will help hold the molten copper in. My only concern with putting nickel on the outside is it is soft and scratches kinda easy. Maybe 15n20 and polish it after etch might work. Here is one I'm working on now. It was a Damascus jacket, copper, and 1084 core.

Wow looks amazing! But now... I have a question. It seems you have some copper at the hilt on the edge. Is there any way for that not to happen? 

[Shane Atwood]

On 1/21/2022 at 9:03 AM, Paul Checa said:

Wow looks amazing! But now... I have a question. It seems you have some copper at the hilt on the edge. Is there any way for that not to happen? 

That is a horrible picture. The copper doesn't come all the way down to the edge. It is slightly above the cutting edge. 

The thickness of your core material and how deep you grind into your blade can definitely determine how far up your copper is on the blade. How thick of copper you use can determine how thick the copper line across your blade is. This blade I used 5/32" 1084 core and about .055 thick copper. My outside layers are Damascus that started out as 3/16" thick material. If I remember correctly my billet started out 2" wide and 7.5" long. Then with forging out the billet my core was thinned down. Also I probably got this billet to hot and melted some of the copper which is why there are thicker and thinner sections of copper, which sometimes makes a cool affect. I will try and get a better pic now that I have this blade hand sanded.