oldandslow
05-26-2018, 07:08 AM
Greetings,
Since I'm doing a load workup for my 30-06 I want to have the cases as consistent as possible. This means I need to anneal the cases which also prolongs brass life. During the last "great bullet hording" when it was impossible to buy bullets I started casting for rifle, pistol and shotgun slugs.
In researching brass annealing I find a bunch of data on gas torch annealing but only a bit of hard data on lead pot annealing- I needed specifically the temp. and number of seconds to keep the case in the lead melt and the prevention of lead sticking to the case.
I did some testing on Winchester 30-06 cases, 9 times fired with annealing every three firings. I'll present the conclusions first and the pics and data last.
1. Lead dipping for 8 seconds into a 15 lb. Lyman pot with a surface temp. of 750-775 deg.F and then wiping the warm case with a cotton rag to remove all the residual lead on the case necks gives an acceptable anneal of the case neck and shoulders and the first 1/8 to 1/4 inch of the case body. The cases were dipped to the shoulder-body junction.
a. this result works well when the cases are uncleaned and tarnished and the fired primer in place. There was no leading on the interior neck. Cases were dropped in cold tap water after annealing to limit heat transfer to the case head.
2. Using new cases without a primer resulted in the most leading externally and internally.
https://i.imgur.com/BoIoLuw.jpg?1
https://i.imgur.com/e2BL8IZ.jpg
https://i.imgur.com/TklROeQ.jpg
https://i.imgur.com/GTswqRN.jpg
https://i.imgur.com/yUXOE38.jpg
Data- 1. It took 30 minutes to get the pot up to temp.- measuring 775 deg.F at the bottom of the pot and 750 deg.F in the first inch of depth (measured with a RCBS dial thermometer). The air temp just above the lead surface was 295 deg.F.
2. I tried various case coatings to decrease lead coating of the cases- namely motor mica, imperial sizing wax and 10-40 oil. All worked to some degree but the best result was wiping off the case with a cotton rag just after dipping.
3. The cases were held in place over the lead pot with a leather welding glove.
The next experiment will be with 450 deg.F Tempilaq to record how the dip times affect the length of annealing down the case body.
Since I had difficulty finding specific info on lead dipping times and temperatures I hope this will provide a starting point for others. Lead dipping has the advantage of a known repeatable temp. and symmetric annealing around the case neck without the guesswork of eyeballing a case color change as with flame annealing. Best of all is that I get to melt lead again which had stopped due to affordable bullets now being available.
best wishes- oldandslow
Since I'm doing a load workup for my 30-06 I want to have the cases as consistent as possible. This means I need to anneal the cases which also prolongs brass life. During the last "great bullet hording" when it was impossible to buy bullets I started casting for rifle, pistol and shotgun slugs.
In researching brass annealing I find a bunch of data on gas torch annealing but only a bit of hard data on lead pot annealing- I needed specifically the temp. and number of seconds to keep the case in the lead melt and the prevention of lead sticking to the case.
I did some testing on Winchester 30-06 cases, 9 times fired with annealing every three firings. I'll present the conclusions first and the pics and data last.
1. Lead dipping for 8 seconds into a 15 lb. Lyman pot with a surface temp. of 750-775 deg.F and then wiping the warm case with a cotton rag to remove all the residual lead on the case necks gives an acceptable anneal of the case neck and shoulders and the first 1/8 to 1/4 inch of the case body. The cases were dipped to the shoulder-body junction.
a. this result works well when the cases are uncleaned and tarnished and the fired primer in place. There was no leading on the interior neck. Cases were dropped in cold tap water after annealing to limit heat transfer to the case head.
2. Using new cases without a primer resulted in the most leading externally and internally.
https://i.imgur.com/BoIoLuw.jpg?1
https://i.imgur.com/e2BL8IZ.jpg
https://i.imgur.com/TklROeQ.jpg
https://i.imgur.com/GTswqRN.jpg
https://i.imgur.com/yUXOE38.jpg
Data- 1. It took 30 minutes to get the pot up to temp.- measuring 775 deg.F at the bottom of the pot and 750 deg.F in the first inch of depth (measured with a RCBS dial thermometer). The air temp just above the lead surface was 295 deg.F.
2. I tried various case coatings to decrease lead coating of the cases- namely motor mica, imperial sizing wax and 10-40 oil. All worked to some degree but the best result was wiping off the case with a cotton rag just after dipping.
3. The cases were held in place over the lead pot with a leather welding glove.
The next experiment will be with 450 deg.F Tempilaq to record how the dip times affect the length of annealing down the case body.
Since I had difficulty finding specific info on lead dipping times and temperatures I hope this will provide a starting point for others. Lead dipping has the advantage of a known repeatable temp. and symmetric annealing around the case neck without the guesswork of eyeballing a case color change as with flame annealing. Best of all is that I get to melt lead again which had stopped due to affordable bullets now being available.
best wishes- oldandslow