03-21-2017, 10:44 PM
(03-20-2017, 02:44 PM)wadebevan Wrote: Hello all,
I just wanted to get a thread started on heat treating.
This is one area that the internet seems to have a lot of conflicting opinions.
If you read enough, you can get a pretty good idea about the process, and what parameters are involved.
For my first blade, I was going to outsource the HT, but, I decided that it was better to learn by doing, than having someone else do it.
I bought a used pottery kiln for a pretty decent price, and promptly brought it to the shop and cut a 6" hole in the lid. (It was a top loader)
After shaping a couple of fire bricks to cover the hole when heating, I started to test with some scraps.
Electric kilns take a long time to get to 1500F!
And cheap thermocouples catch fire around 700F!
How do you measure temperature?
Thermocouple, magnet or other?
What do you use for quench oil?
What temp do you heat your quench oil to, if you do?
Just trying to learn as much as I can before starting blade #2.
Thanks,
TW.
I rely heavily on good heat treating ovens. They're so easy to run.
I still use magnets when I'm hardening a blade with an acetylene torch.
For precise temperatures, I use a couple of Omega hand held units with 18" long, K type thermocouple probes. The most basic hand held that measures to 2000*F would be fine. If you want welding temps of 2500-2600*F, it's more expensive.
Bigger diameter probes last longer for measuring hot stuff, but you still end up replacing them. Nature of the beast.
I use Park 50 and Park AAA quench oil, and heat it to the temperature that gives me a harder blade (hotter oil cools faster) or tougher blade with slower oil (which is generally also easier to use).
I hear people use vegetable oil all the time, but heat treat is Not the Place for Mistakes.
If you have a few blades and want the HT to be Perfect, send them to Brad Stallsmith at Peters HT.
Hope that helps
