Annealing cases in a lead bath, some guidence please


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Andrew Leigh
August 13, 2013, 08:09 AM
Hi,

was given an electric lead solder pot a day or so ago. Is is nice as the bath diameter is 6" so with the right type of jig I could anneal batches of 50 easily on one plunge into the bath. The advanatage of this is that every case in the batch should be nearly identical in terms of annealed status. The other advantage is only one exposure to the lead and no 50.

A couple of question then.
-I would want the lead at a temperature of 750F and immerse the necks for 5 seconds?
- Do I want to quench in water or allow to aircool?
- What stops the lead sticking to the brass?
- How far past the shoulder should I immerse to. Was thinking of between 1/16th and 1/8th of an inch?

Cheers

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Grumulkin
August 13, 2013, 08:18 AM
Hi,

was given an electric lead solder pot a day or so ago. Is is nice as the bath diameter is 6" so with the right type of jig I could anneal batches of 50 easily on one plunge into the bath. The advanatage of this is that every case in the batch should be nearly identical in terms of annealed status. The other advantage is only one exposure to the lead and no 50.

A couple of question then.
-I would want the lead at a temperature of 750F and immerse the necks for 5 seconds?

I wouldn't know.

Do I want to quench in water or allow to aircool?

Either; it doesn't matter with brass.

What stops the lead sticking to the brass?

The fact that you aren't useing flux. Even with solder meant to stick to brass, you have to use flux. That said, I don't think I'd blow my whole wad of cases on a trial run; try at least one first.

How far past the shoulder should I immerse to. Was thinking of between 1/16th and 1/8th of an inch?

I'd go with 1/8th of an inch.

stubbicatt
August 13, 2013, 08:34 AM
I would do one at a time. The problem with introducing that much material at room temperature to the molten lead is that the lead in contact with the necks will congeal and stick to the necks of the inner ones for sure, and maybe all of them, and by the time it heats up enough to release from the casings, you will have ruined them because the heat will have migrated to the case heads which will then be dead soft.

Andrew Leigh
August 13, 2013, 08:56 AM
Great points guys, thanks.

Stubbicat I was hoping that that the critical mass of the 6X2" bath full with molten lead would be sufficient to avoid a dramatic change in temperature. But better safe than sorry.

I will take an old batch of cases that have passed their sell by date and incrementally increase the amount in the jig. I also have a thermocouple and that can also tell me the drop in temp.

I got the 750F from a case annealing manufacturers website who mentioned a few seconds. I took the stab at 5 seconds.

Any other thoughs please let me know.

kelbro
August 13, 2013, 08:59 AM
^^^^^^^ The lead will cool if you try to dunk all 50 in that small of a pot.

There is no difference between one exposure and 500 exposures to the molten lead. I cast a lot and I have for 40 yrs. I get tested nearly every year. My levels hover between 2 and 3.

Get a propane torch, cordless screwdriver and the shellholder from Lee.

Set the flame where it has about 1" of blue.

Get in a dark room.

While counting (one thousand one, one thousand two, etc...) Spin the brass neck/shoulder junction just past the edge of the blue in the flame until it just starts to change color. Remember the final count.

Move out of the dark room. Repeat the process for the count that you determined to just cause a color change.

No need to quench.

If it glows cherry-red, you've gone too far!

You will be through before the lead pot gets molten.

Andrew Leigh
August 13, 2013, 09:17 AM
Hi Kelbro, thanks.

The exposures, was talking about me being exposed to the lead and fumes rather than the case to the molten metal.

Was considering making a automatic flame annealer but for the amount I shoot is simply would not pay back. Had considered the screwdriver and flame approach and had even bought the butane torch for the process.

My reasoning on the lead bath, apart from being free, was that each case would be subjected to an identical process. I am sure the the torch works perfectly but I believed that consistency would be better in the bath?

Cheers

627PCFan
August 13, 2013, 10:56 AM
Get some tempilaq, a propane torch and a lee case holder :) Cheap and works.

homatok
August 13, 2013, 03:15 PM
Annealing case necks by dipping them into molten lead that is held at about seven hundred degrees ‘F’ works well. Wheel weight alloy, which is approximately eighty nine parts lead, one part tin and ten parts antimony, melts at six hundred and nineteen degrees ‘F’ so you can safely set your lead alloy temperature at seven hundred degrees ‘F’. The use of a thermometer will take any guesswork out of the process. The reason for using lead for annealing is to keep the temperature low enough for proper uniform annealing, and that is simply not possible using the torch method. With a torch the case is often heated on one side more than the other, temperatures are not readily repeatable from case to case, and in falling over into the water, one side is quenched before the other.

To minimize the likelihood of lead ‘soldering’ itself to the brass case it is best to use as close to pure lead as possible (although any lead alloy will work). Anneal your cases with the fired primers left in, as that forms an airlock that keeps lead away from the inside of the case. With respect to annealing cases using molten lead, basically you: set the thermostat on your pot at seven hundred to eight hundred degrees ‘F’ pick up each case by the head and dip the neck of the cases about a quarter-inch into some powdered graphite or light oil (vegetable oil is fine). The oil keeps lead from sticking to the brass but, any lead that does stick is easily removed by a quick twist in steel wool while the case is still hot. Shake off any excess oil, dip the neck, shoulder, and about a quarter-inch of the case body into the molten lead and just as you begin to feel an uncomfortable degree of heat in your finger tips, drop the case into water. If you hold the cases in some other way than with your bare fingers, leave them in the molten lead from eight to twelve, but not more than fifteen seconds. When the case is hot enough that the lead does not cling to it, it is annealed. Pull the case up out of the lead, tap on the side of the case to remove any bits of lead (if the lead is really sticking, the case isn't annealed!), then drop it mouth down (straight) into a container that is mostly full of ice water. Following the anneal, it would be wise to closely inspect the inside of the case both visually and with a bent paper clip just to make sure there are no lead drippings adhering to the inside the case.

If you are left-handed, have the cases on the right side, the lead in the middle, and the ice water on the left. The cases go only one direction, to the left, and you use only one hand. If you are right handed, reverse the set-up. Because it only takes a few seconds per case, you can anneal hundreds of cases in an hour with this method. After the annealing process, remove the cases from the water, shake them out and use a piece of bronze wool to clean the annealed portion. This removes any residual lead and/or burned oil. Then, dry and tumble the cases to remove any traces of residual oil and they are ready to process.

Hope this helps.

eam3clm@att.net
August 13, 2013, 09:56 PM
You want to be REALLY careful about putting cold things in molten lead. Your brass may not be the only thing that gets hot, and lead will stick to skin without flux.

FROGO207
August 13, 2013, 10:15 PM
I use a leather glove with the end of the thumb and first two fingers cut off enough to allow me to grip the brass securely when dipping brass in my lead pot. This cuts the heat the rest of my hand is exposed to measurably. Otherwise I do about the same procedure wise as post #8.

Andrew Leigh
August 13, 2013, 10:25 PM
Thanks guys,

going to try the lead bath this weekend, all part of the learning curve. Will be in well ventillated area and will take the necessary precautions.

Will also try the flame method and see which is more convenient.

I fancy the flame will be more convenient while the lead bath should be the most consistent. How I measure this is anyones guess.

stubbicatt
August 13, 2013, 11:34 PM
Do NOT let water splash into the lead pot. If you do this, I would recommend a bucket on the floor so that the splashes won't get in the molten lead.

Really bad things happen if water gets in molten lead.

Andrew Leigh
August 13, 2013, 11:56 PM
Saw a cup of coffee fall into a foundry pot of molten aluminium, was not pretty.

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