I lucked out and found an old used kiln at a yard sale for $25. I added a PID controller and a solid state relay. So many options it makes you dizzy reading them. Works wonderfully and I can ramp up over a set time or I can ramp to temp and hold and then ramp more and hold then ramp down. It seems to hold temp to about +_ 5F*.
So far I have only used it to melt aluminum, but I think it will also be a great heat treat oven.