temperin

[mack79]

Would like to know is anyone knows a good why to temper swords or longer blades that won't fit into a normal sized oven just started making larger blades and my oven is the only way that I know.

 

[stickwhistler]

A way - not necessarily a good way.

Harden the blade - which I presume you've already done.

Get two pieces of flat stock eg 1 inch wide by 1/8 inch thick
as long as the blade ie blade 30 inch = flat stock 30 inch.
Put the blade between the two pieces of flat stock and put in a clamp eg vice or jaws.
Place the spine so that a flame from a torch can play on blade spine
eg if the sword blade is 1.25 inches wide, place the sharp edge 1/2 inch
between the flat stock pieces - allowing 3/4 inch above.

Play a flame from the torch on the sword spine until the desired colour
is just above the flat stock ie the colour travels down toward the edge
(which is between the flat stock). The spine could be blue, and the colour
near the flat stock might be dark brown or straw.
The flat stock and vice jaws will act as a heat sink ie keep the edge cool.
If any tempering does take place, it will not be as much as the spine.
The problem is that the tempering will probably not be even along the blade.

As a one-off this will work, but if you are going to regularly heat treat long pieces,
may I respectfully suggest building a purpose built oven eg using heating elements
and refractory bricks (dismantle a pottery kiln or use spares/replacement parts from one).

Best of luck.

 

[mack79]

Thanks for your help!

 

[Stacy E. Apelt - Bladesmith]

I temper long blades in the home oven.

Place it in the pre-heated oven at a 45 degree angle. The end will stick out the door at the top corner. Bake at the temper desired ( I like 450-475F) for an hour. Reverse the blade and bake another hour. Cool off in running water and repeat.