Heat treat oven?

[Beau Nidle]

Just wanted to get some thoughts from the guys who do their own heat treating, did you buy an oven, or build one? I'm on a couple of other forums and the universal answer seems to be 'why buy, just build your own!'. I'd rather not, but I'd like to hear what you did and why you went that route. A lot of my hesitation comes from A: not having any clue about electrics, and B: a lot of these guys work on hunting knives that seem to use much more forgiving steels when it comes to heat treat, and some of them simply use a forge and eyeball the colour of the steel. I'd like to get some input on kitchen knives.

Thanks in advance!

 

[Kippington]

I'm in a similar boat to you in that I'd like to build an oven/salt pot but I don't have the technical know-how.
So I'm saving up to buy a heat treating oven while doing the best that I can with the forge (charcoal) in the mean-time.

It's an interesting topic. You're right in that we should be shooting for the most accurate temperatures possible, as well as correct soak times (both of which are virtually impossible when your blade is longer then the forge), but it shouldn't be forgotten that it's also possible to make a very good knife without a heat treating oven, using only the eyeball method instead (albeit with a bit of practice and some research).

If you're a hobbyist, have you considered making a knife with a eutectoid steel and using a forge to heat-treat? I'm sure you already know this, but eutectoid steels are very forgiving to mistakes in the HT. Using one is a very good way of getting into the science and methods of heat treating, and you get a good carbon steel knife out of it!

I've noticed that not many people on this forum do their own heat treating, and the ones that do seem to stay quiet about the topic. I can't blame them after reading some threads on other forums - some people can get really nasty on this subject, which is a shame because it's interesting and a lot of fun.

 

[Matus]

I would love to be able to HT my own blade one day, but HT kiln is not a cheap thing and it also takes a lot of testing before you get the results you are after and in a repeatable manner. Once you go for more complicated steels the HT process gets much more complicated and low volume (hobby) production will make it hard to justify to invest the time and cash.

 

[Dan P.]

One can do the hardening/austenitizing step of heat treatment perfectly well in a forge. It does require experience, and if you have a number of knives to get through, the degree of concentration required can be quite exhausting.
If I had the money or know how, I'd get salt pots. I have heard too many bad things about electric HT ovens, even professionally made ones.
Personally I use a home made gas furnace. That's basically a gas forge with a very large chamber so that the heat is dispersed and indirect. I control it with the use of a probe/thermocouple thingy and a digital reader. Cheap, reliable, holds a temperature dead steady, and I know how it works!

 

[StuNY]

I went ahead and built my own after facing same dilemma- build or buy. It was fun, but took a while and I would say is best for people that are into making their own tools... and some electrical knowledge and welding skill doesn't hurt either! I think for most people it will be more cost effective and simpler to just buy one. Highly recommend getting one either way, I really enjoy treating my own knives and do a lot of trickier steels including various stainless. Learning curve for sure though. Good luck!

 

[New2]

I built a forge from an old barbecue and a foot pump and I can HT O1 steel blades up to 61rc. Mine is large enough to process about a dozen blades over a few barley pops in the evening. It's also good enough to anneal metal that is already hardened. It's pretty simple to make a forge, if you look on youtube for 'the king of random' grant thompson he's got a great video on making one from a steel bucket which would be ideal for doing blades. I would not suggest using plaster of paris like he does, I would buy proper refractory cement, it's about the same price.

 

[Matus]

Welcome New2 - and show us a few pictures of that forge!