Andy Dingley wrote:
On Thu, 05 Jan 2006 10:45:21 -0600, Rex B wrote:


So what do people heat this stuff up with, and in?
I'm looking at a ~20" barrel from a Hawken.


Iron kettles. Avoid stainless, wrought or cast iron are better. If you
weld one up from mild steel it will work fine, just not last so long.

Heating should be electric and thermostatic, for easy control. Get some
firebricks and set cheap oven elements into grooves in the top. You
don't even need to grout with fire cement (expansion tends to blow it
out anyway) and you certainly don't need bare-wire elements. The only
expensive part is a good controller - any industrial electrical supplier
will have these and they're still cheaper than most kiln specialists. A
kitchen "simmerstat" or triac phase controller is almost enough, but you
have to guard manually against overheating - these just control power,
not temperature. Accurate thermocouple meters are dirt cheap these days
- crazy not to have one.

Nitrates are available from lab chemical suppliers. They _will_ still
deal with you, if you're patient. Failing that you can use fertilisers
or refine horse urine (crystallised leachate from a big pile of used
bedding straw is simpler to work with than draught). The purity you need
is trivial in comparison to pyro uses.

An awful lot of successful hot bluing gets done on the kitchen stove in
a stainless fish kettle. It works OK, but I wouldn't recommend it - this
stuff is just too hazardous. Personally I only work on stuff this crazy
if I'm outdoors and "firefighting" can just be a question of leaving it
to burn itself out.

Sounds like a lot of effort for a single barrel.
Thanks for the detailed response.