Using Clay

JW Knives

JW Knives

Joined
Feb 22, 2011
Messages
566
Hey guys,
I'm relatively new to knife making. My dad set up a shop last year and I use it from time to time. Can somebody please briefly explain or direct me to a thread that talks about using clay on the blade during the heat treat. Is this simply aesthetic or does it change hardness?

Thanks
Jay W
 
A knife is hardened by being quenched from a critical temperature fast enough to convert into martensite. Too slow, and you form other structures such as pearlite. The purpose of clay is to hold the heat, thereby slowing down the quench in the portion of the blade covered in clay while the exposed portion of the blade hardens. Too much clay on the spine can prevent the entire blade from hardening. It really doesn't take much to slow a fast quenching steel like 1095 or W2 to create a hamon.

The point of clay is both aesthetic and functional as Shadow mentioned. The hamon is a line of transition from one structure to another (i.e. separating pearlite and martensite). In this day in age with the quality of steel we have, it really serves primarily a decorative purpose, but it does leave a somewhat softer spine and a hard edge. And it is hard to beat the beauty of a well crafted knife and a beautiful hamon.

The count's link is an excellent account of how it's done. And Knifedogs is another site worthy of your membership.

--nathan
 
You must log in or register to reply here.
Back
Top