lead pot annealing with data and pics

[oldandslow]

Greetings,

Lead pot annealing has some advantages to us boolit casters as the case is subjected to a uniform heat without the risk of getting too hot as with a flame setup. The temps are measured and repeatable giving more consistency than eyeballing a color change of the heated brass.

I'll give the conclusions from my testing first with the data and pics at the bottom.

1. An 8 second dip in a lead pot at a temp. of 750-775 deg.F is both safe and effective without significant case body or case head annealing.

2. There is almost no lead sticking (internal or external) to the multiple uncleaned fired cases with the fired primer in place when it is wiped off while the case is still warm. Annealing new cases without the primer in place gives the most leading- both inside the neck and along the exterior.

Data- a. 15 lbs lead alloy in Lyman pot- 30 minutes to heat to 775 deg.F at bottom of pot via RCBS dial thermometer, 750 deg.F at surface of pot. Dip was done at 8 seconds to shoulder-body junction, then dropped in a bowl of tap water to limit any case body heat migration from neck and shoulders.

b. air temp just above lead surface was 295 deg.F

c. cases were 30-06 Win. 9 times fired and annealed twice before after 3rd and 6th firings.

d. some but not optimal reduced leading with 10-40 motor oil on neck and shoulders. Same for motor mica and Imperial sizing wax.

Next step is to apply 450 deg. Tempilaq to case body with different dipping times to see extent of heat migration down the body.

best wishes- oldandslow

 

[Unclenick]

Fred Barker recommended dipping the necks and shoulders into graphite powder to prevent soldering.

 

[lordmorgul]

I’ve started using this technique but with steel blasting shot in the pot instead, providing a non-stick self-standing medium that cannot splash or otherwise get dangerous from contaminates like molten metal or other liquids. Got the idea from another post, will provide link in edit.

Annealing with Hot Sand?
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Andrew - Lancaster, CA
NRA Life Member, SAF / CRPA / FPC member and supporter, USCCA Member

 

[Unclenick]

The only thing about shot and sand is you get less intimate contact with the brass surface, so the required time will be greater. Some sort of Tempilaq would be of use here. With intimate contact like the molten lead, once the center of the neck wall has reached 750°, only about 3.5 seconds are needed for stress relief. Less intimate contact will make it take more time to get the middle wall up to temperature. It can be calculated or modeled, but measuring is always best.