I’ve never done mokume (I hope to someday), but working with
glass where I have to have precise temperature control, I do
have a lot of experience with kilns and controllers. I think
there are options out there which are much less expensive than
buying a commercial kiln with a built-in controller.
I have three kilns, and run all of them with one separate
digital controller hooked to a thermocouple. I got my controller
through Arrow Springs (a hot glass supplier), and the owner Craig
Milliron configured the controller to accomodate the
configuration of my existing plugs and receptacles. All you need
is a kiln with a hole in the side to insert the thermocouple.
(This is a rod about a foot long and about 1/4 inch in diameter.)
He sells more than one version, depending on the number of
stages you need. The least expensive is a “set-point” controller,
which takes your kiln up to a temperature you set and holds it
there indefinitely until you turn it off. Next, are the digital
controllers which allow you to “ramp” the temperature up or down
at a certain number of degrees per hour (essential for glass).
Most are “four stage” controllers, meaning you can program four
separate heating/temperature rates per program. And they become
more complex from there, with as many as several dozen stages
possible. For any digital controller, you’re looking at something
in the $300 - $450 range. I just purchased a 55-stage controller
for $450; that included his labor to configure it to my specs,
and adapt it to my existing set-up. This is still much less
expensive than the simpler 4-stage digital controller that is on
the Neycraft and Paragon kilns.
You can also purchase controllers through large ceramic
suppliers. They also will build kilns to your specs. I’ve just
had Seattle Pottery build me a small crucible kiln for about
$225, and I know they sell an Orton digital controller for about
$325. I think the Orton is a 4-stage controller, which would
allow you to do just about anything you’d need in metalworking.
If you buy a commercial kiln with a built-in digital controller,
plan on spending about $500 just for the controller, over and
above the cost of the kiln. The beauty of designing your own
system and having it built is that you can get it for much less,
and your controller is “portable” and can be used with any other
kiln you have or decide to buy in the future (such as a burnout
kiln, enameling kiln, etc.).
Hope this helps -