case annealing

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Sharps '63

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Even though I wasn't having a problem with case mouths splitting, I just annealed 100 Winchester 45-70 cases that have been reloaded and full length resized many times. That's twice I've done it -the FIRST and the LAST time!
I sure hope it was worth the time and aggravation.

What do our resident experts have to say on the topic, and what methods have they actually tried, not just read about?

Todd
 
I anneal my cases every 4 or 5 shots. Sit them on an aluminum block in a bread pan of water with about 1/4" of water above the base of the shell. Heat to low red hot and tip into the water

cheers mooncoon
 
Sharps 63,
Prepare a large container of cold water, room temp, with a large opening, a plastic bucket will work fine.
Get a good pair of oven mitts ready and handy. Then preheat the oven to 475-500 F.
Then I fill an eight inch cake pan with about 1 1/4 inch of hot water.

Put it on the oven rack, pull it out first, then add the deprimed/cleaned cases to the water/pan so they are case mouth up resting on the base. The inside of the cases should fill with water.
Gently push the rack into the oven and close the door.
The water will start boiling very quickly and the cases will also heat very quickly.
Allow the water to boil away until there is about 1/2 inch left in the pan.
Then with a prefilled container of cold water handy, right beside the oven, dump the contents of the cake pan as quickly as possible into the cold water.
Time is critical, don't take the time to try to do this nicely, or comb your hair. Dump them fast. Your brass should now be annealed properly and soft.
bearhunter
 
i like lead pot annealing myself, brass anneals at around 650F and lead melts at about 625F or so. i leave the spent primers in the cases and smoke the out side of the case with a candle, the spent primers keep the lead from flowing up inside the case mouth and the smoking just protects the outside. i dip the case in the molten lead just past the shoulder with my bear fingers till they start getting hot then toss the case in a bucket of water. i reload 3 differnt wildcats, moving shoulders back and blowing out case walls and necking down up to 90 thou and i allways get excellent consistent results.
 
The molten lead one sounds interesting. I will try that next time. I use the pan of water...heating until almost red hot and tipping into the water. It works just fine for me and I have never had a neck split yet. Dave
 
In a darkened room, with the propane torch on low, hold the case between thumb and index finger and rotate the neck area in the flame. Once the colour red begins to appear, dump it into cold water.
 
Probably the most poorly approached and understood topic in reloading. I am going to get wordy on this one. I will make two posts, one explaining the problem, the other listing some different solutions (though I do not think any are ideal).

I have had bottleneck rifle cases in caliber .233, .250 Savage and .308 Win. split on me. It depends on the brand of brass when it starts happening, but it mostly seems to come in the 3rd to 5th firing. I full length resize all calibers I reload.

Cartridge brass is 70% copper, 30% zinc, and is formally referred to as UNS C26000 brass. It is an extremely ductile material when its crystals are large and evenly formed. But, every time it is deformed while cold, its crystals likewise deform, and are broken into smaller, distorted crystals that don't allow smooth deformation. This process is called work hardening and occurs in all metals. As it proceeds, the metal becomes stronger, but less ductile (more brittle), and will eventually fracture under load, instead of deforming.

To undo this, we need to recrystallize the metal, to restore the large size and even shape of the grains. The recrystallization temperature of C26000 is usually given as 290 C, which means that if the metal is heated to this point, it will spontaneously recrystallize.

Take a look at the graph on page 29 of this document. It shows the effect on the hardness of brass of heating to different temperatures.
http://web.nchu.edu.tw/~jillc/me/Ch10-%20Kinetics%20-%20Heat%20Treatment.pdf

Bearhunter is annealing at 500 F in his oven, which is about 260 C. Looking at the graph, we see that he is barely starting to soften the brass at this temperature, and is probably reducing the hardness only about 2-3 points on the Rockwell 'H' scale.

Sawdust's molten lead bath is at some temperature over 327 C, and if he we assume he is a bit over that, he could be at 350C, which is the inflection point at the upper end of the recrystallization range. Figure he is dropping the hardness about 15 points, HRH.

Several people have mentioned heating the brass until it starts to glow red. All metals luminesce at around 700 C. Going back to our graph, these people are reducing the hardness at least 35 points HRH. Note that the people who made the graph discontinue it around 750 C.

For what it's worth, Matweb.com lists the annealing range of C26000 as 425-750 degrees C. This indicates that these are the temperature limits to what may produce viable results, usually in commercial practice. Lower than that, you are not doing much good, higher and you are making the brass way too soft to be practical, and risk oxidation attack which may destroy the metal.

Hornady is the only manufacturer to attack the issue. They offer an "annealing system", which is just a case holder and a bottle of 475F Tempilaq. Tempilaq is a liquid that looks like nail polish that changes temperature at a set point, in this case 475 F, which is 246 C. I applaud their effort to do something about the witch's brew of bad practices in the world of cartridge case annealing, but I really think they need to step up to a higher temperature. But, the fact that they are selling this and apparently having some good results with it adds to the data from Bearhunter and Sawdust that we really want to just be at the top end of the annealing range to get the best results, and the ideal temperature for home cartridge annealing is likely 275-350 C (525-660 F).
 
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The pan-and-water method is the most common. It has been described in reloading manuals and gun magazines for years. Basically, you get a pan, fill it with water to some depth above the case head of the cartridge, and stand the case up in it. Then, you heat the neck with a torch until it starts to glow, and tip the case over. I have done this, and it works, but I really hate this method.

For one, I think any method that heats the brass until it glows is 300 degrees too hot. The brass comes out so soft you could crush the mouth flat between your thumb and index finger. It is inconsistent, as lighting conditions will dictate when you notice the brass glowing. You tend to heat aggressively, to hurry the process, and with the temperature of the case rising at probably 100-200 degrees per second, every case comes out a bit different. It is hard to reach the back of the case, unless you are walking around the pan while heating, so you anneal more on the front and sides than the back. If you are a bit slow removing the case from the flame, the metal oxidizes and turns black, and I believe the life of such a case would be shortened considerably. The process is messy, I always ended up with water everywhere and the cases needed a couple of days to dry in my basement.

It also leads to a pet peeve of mine, which is people start believing that the quenching in water is a crucial part of the process. It is not.

To repeat: IT DOES NOT MATTER HOW YOU COOL THE CASES. You can drop them in water, you can remove them from the heat and allow to air cool, you can turn the oven off and let them cool over a period of hours. The hardness will be the same (though the oven cool method will effectively make them a bit softer, in practice).

The water in the water-and-pan method is there for two reasons. One, it gives you a way to cool the cases quickly so you can handle them without burning your fingers. Two, and by far the most important, it prevents the case head from overheating. This is the only hard and fast rule of case annealing: DO NOT ANNEAL THE CASE HEAD. Doing so will result in case failure at time of firing, and a ka-boom on a large scale.

Bearhunter's method is interesting, but I think the temperature would ideally be a bit hotter, especially with short cases, since the brass close to the water line will never get up to the temperature in the oven. Also it sounds really time consuming. How long does it take to boil off 3/4" of water? And his cake pans must be flatter than mine, I always got frustrated trying to stand more than half a dozen cases up at once. It seems inevitable that one will land on a warped spot in the pan, tip and domino over dozens of other cases. Also, don't let the water boil down too far, or you will soften the case head. And what is with the haste to dump in the bucket at the end? I don't understand the point.

In the end, cases in an oven set to its highest point, with the heads constantly submerged, should produce good results. The heating would be even over the exposed metal and much easier to control than any torch-in-hand method. It would be very intersting to try this, taking the time to build a case holder first and maybe borrowing the idea of getting some Tempilaq to see how long it really takes to get the brass hot enough.

Sawdust's method of molten lead is tried and true. Lots of commercial heat treating is still done in molten baths. Heating is rapid, easy to control and you can easily control which parts of the case you are annealing (ie head and neck) simply by which parts you submerge. The only problem is that many people don't have an adequate lead pot, heater, ventilated area etc. to do this, and many people don't like the idea of working with pots of molten lead at all. Also, make sure your cases are absolutely dry! A drop of water inside a case could make a big, painful mess.

I have tried chucking a case in a Lee case trimmer holder, chucked in a drill, and spinning that in a torch flame set low, and watch for the change in colour of the mouth. Ever look at a military brass case, with its rings of gold and blue oxides at the neck? That is what I was trying to watch for. The case mouth should reach that point well before enough heat conducts to the head to soften it, but in practice it made me nervous. Without the water on the head, or some way to monitor it, I just had no idea how hot the head was really getting.

So, next I simply held the .250 Savage case head in my fingers, and turned up the torch to heat the mouth a little faster. Spinning the case as fast as I could in the flame, when I felt the case head start to get warm I dropped it onto a damp towel. I adjusted the flame so that the oxides on the brass had changed colour all the way down the neck by that point, and I thought I had a pretty good system. The only equipment was a torch and a towel, the brass was ready to reload in minutes (no drying required), and by the time I had done 20 cases, the consistency was pretty good.

The problem? Two of the cases split on the next firing (the cases had been fired four times before the annealing). Clearly, I didn't quite get them hot enough, at least, not all of them.

I intend to keep playing with annealing as much as I can. I believe in the necessity, I understand the science and I am determined to find a simple, reliable method that allows the handloader to anneal brass cheaply and quickly, with regular, even heating and no chance of softening the case head. Ideally, I would like to see the annealing of 100 cases reduced to a half hour job, with perfect, repeatable results.
 
BattleRifle, I will try the oven a little hotter next time. Thanks for the extra info.

I find that I can do as many cases as the cake pan will hold in about 1/2 hour or less. Once that water starts to boil, it doesn't take long to disappear. Ilike to give it the extra time to normalise the metal thoughroughly. I work in a glass bottle manufactureing plant and we have to anneal the glass to an ideal softness, the methods are the same as is the technology for metal. The main problem is that the temp must be consistant all the way through. We find that a soak time is needed at or slightly above the ideal normaliseing temp. Glass and iron are different from brass in that by "quenching" or rapid cooling after the the proper temp has been reached, overhardening occurs, as well as destructive stresses form. From what I've read, if the brass isn't quenched quickly, hardening and stresses occur. As you say, this may be untrue, but my source was Norma about 30 years ago, when they would still give that kind of info out. They use the molten lead method when reloading military brass for range use.

I would also like to mention that most of the brass handloaders use isn't really hard, just much less ductile, so doesn't take much softening. You mention the brass getting to soft, you're right there, and it does effect neck tensions and not well.

100 cases/half hour is easily doable with the oven/water method. I sometimes do many more than that with smaller cartridge cases like the 223Rem.

Thanks again for the heads up on temps and the metalurgical structure of the brass. I realise that the ratios are just a guide line depending on manufacturer. I looks like the cartridge makers are getting less consistant batches of metal all of the time. Some of the latest Winchester stuff, hardens extremely fast. bearhunter
 
Credit goes to Jerry Teo (Mysticplayer) for this fantastic method. I shoot alot and I use all Lapua brass so annealing became a matter of economics.

To hold my shell cases I use a deep socket from a socket wrench set. I use washers inside the socket to adjust the height of the shell case so the neck is all that sits above the leve of the socket.

I use a socket extension to hold the whole gizmo.

Apply welder's pencil to the neck shoulder junction of the brass case - the stuff rated for 700 degrees. Apply the heat and rotate the socket in the flame. When the welder's pencil changes, I dump the whole works in water.

Ta-da.

Easy, accurate (Judging heat by the color of the glow is crude at best) and effective.
 
Annealing is something I have been wondering about for a long time, I buy Lapua brass when I can because it comes annealed, but I have a rifle coming that Lapua does not make brass for, I have read your posts with interest, anyone have any comments on the following system?

http://www.6mmbr.com/annealing.html
 
All commercial brass has been annealed. Most manufacturers polish after annealing, so you can't tell just by looking at the brass
 
I would like to see a gadget making use of an induction heater and a bimetal switch to actuate a relay to stop the heating and drop the cases into a pail of cold water.
Could be automatized easily.
PP.
 
Here is the high tech solution: http://www.6mmbr.com/annealing.html

I just use the propane torch and tray of water method. I don't heat to first glow, I play the torch around the neck from all directions and bump the case over with the tip of the torch when I see blue temper colour down to the case shoulder. I know this is a bit imprecise but it has worked for me.

I mostly neck size for my bolt actions and anneal when I feel the sizer ball starting to get stiff when pulling back through the case neck. I have some Norma .308 brass that I have reloaded over 40 times and they just keep going. I keep reloading this Norma brass just because I want to see how long I can keep loading it.
 
roberti11 said:
... I have read your posts with interest, anyone have any comments on the following system?

http://www.6mmbr.com/annealing.html
Click to expand...

I have read through that article a couple of times and think it is the best, most factual thing I've ever seen as regards annealing for the handloader. Not surprising when you see the number of things that the writer and I agree on. He also wants an automated, simple method of annealing that keeps the cases dry, heats evenly and does several hundred cases per hour. The editor also suggests to Hornady that they step up to a higher temperature indicator with their system. Clearly he and I are of similar mind.

As to the BC Light annealing machine, I think it looks great. I don't suspect they sell a lot of units at over $300, but if someone annealed tons of cases, it might be the way to go.
 
PerversPépère said:
I would like to see a gadget making use of an induction heater and a bimetal switch to actuate a relay to stop the heating and drop the cases into a pail of cold water.
Could be automatized easily.
PP.
Click to expand...

I also think that induction heating would be the ultimate solution for an automated setup. I got a quote from a company that engineers their products in the US but has them made in China to save money, and it was still over $3000 for the induction power supply. I don't think we are going to see any home reloaders with one of those anytime soon.
 
Bearhunter - I was under the same impression with quenching in iron/steel versus in brass or copper.

I haven't worked brass, but I know to make copper easily workable you quench it quickly, as it will be softer, and to harden copper you cool it slowly, the reverse of iron or steel.

However, like I said, I've never done that with brass, but I should have a more definitive answer once I get my forge back up and running:)
 
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