MANY Australian shooters are handloaders.
That is, they assemble live cartridges at home, and annealing is a core handloading skill.
Annealing means heating and cooling specific parts of our brass cartridge cases, because those parts are beset by strain hardening (often wrongly called work hardening).
That is, the brass has become less ductile, less malleable and less elastic, so it's no longer able to fulfil its given tasks properly.
Annealing restores the brass to a fully functional state, if done with skill.
On February 3, we delved into the basic metallurgy of brass cartridge cases - things we need to know before we start annealing. This week, let's look at some "how to" stuff.
For heat, we can use a gas torch, a lighter fluid torch or molten lead in a pot.
Torches should offer a small, pointed flame whose temperature is widely adjustable.
Similarly, if we opt for molten lead, we must be able to alter the lead's temperature, so the pot's heat source must be controllable.
Ignore often-heard talk of heating the brass to "cherry red". Cherry red is the enemy.
A full, bright red says the metal is way too hot, has gone dead soft and is probably burnt. "Burnt" means the alloy has lost some or all of its zinc, so it's ceased to be cartridge brass and can't be restored.
Trying unsuccessfully to reach a cherry red is almost as bad, for the alloy still gets too much heat for too long, with dead soft brass as the result.
The following method suits torch owners.
We'll look at two other methods, both more refined and capable of the best possible results, in future columns.
In a darkened room or shed, stand the cases in cold water deep enough to cover the lower third of their bodies.
Ensure good ventilation.
Let your eyes get used to the dark, then anneal one case at a time, like this:
Play the tip of a small, hot, pointed flame on the upper half of the case's neck, from a horizontal direction.
I repeat: horizontal.
If the flame has a noticeable downward angle, the anneal can run into the shoulder area and beyond, often so fast that you won't have time to stop it travelling too far.
If you can rotate each case while applying the flame, perhaps by rotating the dish in which they are standing, a more even anneal will result.
An old turntable or lazy Susan can help.
Alternatively, move the torch around the neck.
As soon as you can detect a dull, red glow in the brass, tip the case over into the water.
React quickly.
Don't study the colour or wait for it to intensify.
If the results are disappointing, try again, either shortening the glow time or allowing the glow to suffuse more of the case neck.
Experiment and practise with reject cases first, of course.
Finally, wet cases have to be dried inside and out.
Patient air-drying is best.
Be wary of the kitchen oven: if you must use it, set it at 65C maximum, or less, to protect the temper of the case heads.
Next column: A field day for gun dog owners is coming soon.
