Annealing in a Casting Pot?

Yeah, I would call it a thermostat too.
wide range, but still it is not an on/off switch.

besides that, this amounts into a pissing into the wind competition, no one wins.
 
Wasn't trying to piss in the wind, just pointing out that Lee pots don't have a temperature control that is capable of accurately regulating temperature to the degree that might be expected from a "thermostat". Anyone who reads that is free to decide the relevance for themselves with my blessing. :)
 
My pot is an unmodified Lee Precision Melter. The thermostat (I will call it that because it does control temperature within a band, though it seems to do that with a simple timing circuit that controls how often it is energized, rather than a feedback control) on mine is much better than jethunter gives it credit for. The variability in temperature I have seen in Lee pots seems to be a result of falling liquid levels: as lead is dispensed, there is less liquid to be heated, and leaving the thermostat set a particular output level results in rising temperatures.

When annealing the liquid level does not fall appreciably, and back when I monitored the salt temperature constantly with a thermocouple I found that if the thermostat was not adjusted the pot would hold a salt bath in about a 5 degC range if it was not being used. Once annealing began at full speed, the temperature dropped about 10 degrees.

Theplantguy looks like a good find. He is requesting ID to buy the salt, which shows he seems to be aware of and is following the regulations that drove most retailers out of the business. I paid $17 for a kilogram five years ago, so $6 /lb is a very reasonable price.
 
For those thinking of reconstructing my setup, I maintain the case holder is the most important part of the setup. Without a heat shield, you cannot work over the bath without experiencing painful radiant heat on the knuckles. It also controls the level to which the case is immersed. I made mine from thin stainless steel sheet and tube, GTAW welded together. But one guy down in the US who copied my setup told me he built one using threaded rod for the "legs" and jam nuts to hold the shields in position.



Note that with mine, the legs don't function as legs, they serve to house the thermocouple (when I use one) and position the shields. The holder actually hangs in the pot, supported by the larger diameter shield on the pot lip.
 
Thanks for sharing your info Battlerife. I'm thinking of jumping on the salt annealing bandwagon as well. As for temps, I was looking up KNO3 info and saw 400C listed as the BP. How are you getting up to 600C?

Properties
Molecular formulaKNO[SUB]3[/SUB]
Molar mass101.1032 g/mol
Appearancewhite solid
Odorodorless
Density2.109 g/cm[SUP]3[/SUP] (16 °C)
Melting point334 °C
Boiling point
decomposes at 400 °C
 
That's interesting, juanvaldez, I checked my copy of the Handbook of Chemistry & Physics and it gives the same information you show. On the other hand, the MIL spec I referenced earlier lists the max. working temperature of potassium nitrate based baths as 593C and the decomposition temps as 635C. I can only assume that when I was getting started I relied on the MIL info and either missed the other published numbers or chose to ignore them.

In practice, the bath starts to fume noticeably right around the 600C mark, with the fume volume increasing exponentially as the temp rises. I haven't taken it over about 620C. I'm guessing the 400C number marks the point where decomposition becomes a thermodynamic advantage, but the kinetics are slow. Like having iron in air, theoretically it is decomposing, but in practice the reaction is so slow that we can make use of the steel in the meantime.

I have always wanted to experiment with an induction based home annealer, I think it would be the ultimate in a fast but tidy process. I even went so far as to price out a couple of radio frequency power supplies several years ago, it looked like it was going to be over $1000 just for the electrical unit, so I gave up and went looking for other things.
 
I've got this guy at work, was thinking press mounted with a micro switch that activates a timer/power relay once case is raised




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I have "heard" about laws working with open flames in city streets and roads being restricted to trades, but they are meaning tiger torches and propane soldering torches.

never actually seen it written.
 
BattleRife, how do you heat up your PN? I tried heating a batch and ended up looking like I burnt it.
I'm guessing start on low and slowly heat the mix up to temp.
 
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