Annealing cases

[Sharpie]

The effects of fully annealing, or stress relieving at lower temperatures, of brass, is not something easily quantified. Brinell hardness is not directly related, though relatively easily measured with simple tools. It's the change in ductility that matters.

Eking out the maximum life that you can get from cases is worthy, but you'll never make them as good, or any better, than they came from the factory. IMO. They are a consumable.

The "rub them with soap and twiddle them in a flame until it turns black" seems as good to me as any other method, certainly worth a try, before investing in and experimenting with a Gucci machine to run through them by the hundred. Unless that's the sort of scale that you are actually using, or are using very expensive cases, belted magnums etc, where it makes sense.

Nevertheless it's not all about plain economics, it's a fascinating subject, and I confess to having tried my own ideas on brass that could really benefit, .303 and 30-30 specifically. Doubling the case life from say ten to twenty uses might even save me maybe 2p/bang, ignoring the set-up costs, gas, my time, etc..

 

[triggersqueezer]

looking at the cases a few posts above they do look good and ones i have had done through an amp annealer look very similar.i guess i'm way over doing mine then because mine look more like lapua in parts and burnt in other parts . but to date they shoot ok.

 

[1066]

Here's one of my homemade machine running some 7x64 cases through.

 

[triggersqueezer]

now that is annealing done right .nice job of the machine.

 

[Ronin]

Six seconds with a MAap gas flame and appropriate deep socket in a hand held drill has worked for me for the last ten years

No need for machines or indicators

 

[Milligan]

Why?

Is it more precise in its results, or less costly for the OP than a bar of soap?

What do you find are the advantages?

Alan

Because the temp of the salt is the annealing temp, no chance of going over so no guessing.
And because we needs more converts to the dark side.

All told it's not an expensive adventure, bout £60 and some time.

 

[Alantoo]

Because the temp of the salt is the annealing temp, no chance of going over so no guessing.
And because we needs more converts to the dark side.

All told it's not an expensive adventure, bout £60 and some time.

fair enough!

Do you end up with the same colours as new Lapua? Any photos?

I did try and fail with molten lead, so reverted to the torch, And then realised I could use the soap to confirm the 400 temp.

Alan

 

[Milligan]

fair enough!

Do you end up with the same colours as new Lapua? Any photos?

I did try and fail with molten lead, so reverted to the torch, And then realised I could use the soap to confirm the 400 temp.

Alan

I even wrote it up
Salt annealing, my journey

 

[Alantoo]

I even wrote it up
Salt annealing, my journey

Interesting. Did they all come out the same as the one you show in the write up... how repeatable did it prove?

I am still wary though because you are still relying on time to arrive at a temperature rather than the more logical (for me) temperature indicator.

How stable were you able to maintain the temperature of the salt or did you vary the time depending on the thermostat / temperature cycle?

One advantage I can see with the salt bath though over just counting loud or other timing in a bare flame, the lower maximum temperature of the salt means less risk of overheating if held too long.

Recrystallisation hardly gets going between 400 and 500. So neck tension would not be unduly reduced even if the neck was taken to the full 500. But like all the stress relief or annealing systems provided you can repeat the process consistently through the entire batch, the neck tension will also be consistent through the batch once you get it to 400 or above.

One of the others advantages I think of the burnt soap indicator is that you are also able to reproduce the results with subsequent batches. It reduces the chances and/or degree of variation between batches.

Thanks for sharing.

Alan

 

[Sharpie]

Because the temp of the salt is the annealing temp, no chance of going over so no guessing.
And because we needs more converts to the dark side.

All told it's not an expensive adventure, bout £60 and some time.

The temperature of the molten salt is simply that to which whatever you cook it up in has reached. Control it with e.g. a thermocouple and a PID and you can set it to whatever you want. To melt it takes a certain minimum temperature, but you can then get it a lot hotter, if not under control.

As with molten lead. If just relying on heating it up until it melts, be aware that once it is alloyed, e.g range scrap, the melting point drops greatly, and it won't do anything useful at that temperature. Pure lead, if you have it, does work, or any old alloy if you have a way of monitoring the temperature (a thermocouple and meter is not expensive, or a decent IR thermometer).

Actually, modern zinc wheelweights might be more suitable, their melting point is higher, and in the right range, though I haven't tried that, and think it might stick to the brass if it is clean.

Or you could just try the old-fashioned way, stand them up in a load block in a tray of water to just below the shoulder, then zap them with a mapp torch, no more than to get them just glowing dull red, in darkness.

You don't need to quench brass afterwards, it's just a time and temperature process.

Once done, do a re-size or two to work the brass and restore some of it's properties, you don't want it dead-soft.

Twiddling in a flame seems to be the principle behind everything else. Personally, if wanting to make a dedicated setup I'd be looking at induction heating. Which is what I think the manufacturers mostly use.

 

[hybridfiat]

I sit mine in a bowl of water on the turntable of my engraver polisher. I play the flame on the neck as it revolves and flick it over into the water when it reaches the right colour. Then place the next one in and do it again.
Alternatively chuck it in a bench drill loosely and at low speed heat it. Then at the right colour lower it into a bowl of water. A bit slower but it means only the neck gets wet.

 

[1066]

In my experience, using the colour of the case as a guide to correct temperature can be very misleading as shown in the photo in post 7. Here srvet shows annealed cases that are not a classic "lapua" blue but look well annealed.

I wet tumble all my rifle cases with SS media, if I anneal them straight away I find hardly any colour change, if I anneal the same cases a couple of weeks after tumbling I get a classic blue look. This is obviously due to surface oxides picked up over time.

I've tried the soap trick and find it's a good reliable heat indicator and works as well as commercial heat indicators for our purposes.

 

[Milligan]

Interesting. Did they all come out the same as the one you show in the write up... how repeatable did it prove?

I am still wary though because you are still relying on time to arrive at a temperature rather than the more logical (for me) temperature indicator.

How stable were you able to maintain the temperature of the salt or did you vary the time depending on the thermostat / temperature cycle?

One advantage I can see with the salt bath though over just counting loud or other timing in a bare flame, the lower maximum temperature of the salt means less risk of overheating if held too long.

Recrystallisation hardly gets going between 400 and 500. So neck tension would not be unduly reduced even if the neck was taken to the full 500. But like all the stress relief or annealing systems provided you can repeat the process consistently through the entire batch, the neck tension will also be consistent through the batch once you get it to 400 or above.

One of the others advantages I think of the burnt soap indicator is that you are also able to reproduce the results with subsequent batches. It reduces the chances and/or degree of variation between batches.

Thanks for sharing.

Alan

Pid keeps it within a few degrees of setting.
I use a metronome app on my phone for timing. Either way, if you leave it in the salt it still won't exceed the temp.

Seems pretty consistent.

 

[Yorric]

I do anneal for all my reloads (made a machine similar to the one 1066 shows) With the gas burner it gives extremely consistent results, mostly down to the easy fine control of time the flame plays on the cases.
I did a lot of work over three years on induction heating annealing, but found that the control systems needed are much more difficult to design & produce, also the process is quite delicate needing very tight control. The automatic case handling is much more complex & requires more precision than a simple motor speed control as used in the gas type.
The designs adopted by 1066 & myself are virtually "hands free" as shown in the video & we just need to keep an eye on it all for safety once it is loaded & running.
You don't need to water quench the brass. I cool the brass under a fan just to make handling more comfortable.
You cannot use the colour of oxydation of the brass as a guide to temperature as 1066 said. Even the same make of brass can come out differently coloured if not all cleaned exactly the same way before annealing. Even a batch cleaned yesterday will colour up different to one done today.
I have Tempilaq but never use it now because when it is painted onto the outside surface of a case & heated in a flame that heats first before the brass & hence doesn't IMHO read true.
As previously stated the annealing process depends on both temperature & exposure time.
To set the gas annealer I run a test watching for the change in flame colour to yellow. I then note the time it appears & set the speed to give an exposure time just less so that no flame change is visible.
That has proved over thousands of cases of varying sizes processed to provide what I need. I.e. consistent suitable neck tension and at least double the case life. NB Cases usually fail due to primer hole issues before I get splitting.

Ian
.

 

[fizzbangwhallop]

These were the .20Prac case I salt annealed a couple of months ago using the Ballisticrecreations case holder in the Lee pot...... having heated the salt cautiously up to 530c I turned the pot down and annealed 'til the temperature reduced to 520c, then turned it back up to 530c etc etc. These cases were in the salt to a steady count of 4 and then into a jug of hot water on the floor well away from the pot.



Following on from that I've since made another case-holder with an adjustable deck-height to avoid messing with the level in the pot and the next step is to ad a PID to accurately control the Lee pot's temperature..... work in progress.



That dirty 7mm RemMag case is only in there for illustration........ I run my cases through an ultrasonic cleaner as a first step.

Fizz

 

[Milligan]

These were the .20Prac case I salt annealed a couple of months ago using the Ballisticrecreations case holder in the Lee pot...... having heated the salt cautiously up to 530c I turned the pot down and annealed 'til the temperature reduced to 520c, then turned it back up to 530c etc etc. These cases were in the salt to a steady count of 4 and then into a jug of hot water on the floor well away from the pot.

View attachment 128352

Following on from that I've since made another case-holder with an adjustable deck-height to avoid messing with the level in the pot and the next step is to ad a PID to accurately control the Lee pot's temperature..... work in progress.

View attachment 128353

That dirty 7mm RemMag case is only in there for illustration........ I run my cases through an ultrasonic cleaner as a first step.

Fizz

Fyi. I bought a pid off evilbay for sub 15 quid and an IP box from local electrical shop.
Your setup is way cleaner than mine...

 

[ChesterP]

I do anneal for all my reloads (made a machine similar to the one 1066 shows) With the gas burner it gives extremely consistent results, mostly down to the easy fine control of time the flame plays on the cases.
I did a lot of work over three years on induction heating annealing, but found that the control systems needed are much more difficult to design & produce, also the process is quite delicate needing very tight control. The automatic case handling is much more complex & requires more precision than a simple motor speed control as used in the gas type.
The designs adopted by 1066 & myself are virtually "hands free" as shown in the video & we just need to keep an eye on it all for safety once it is loaded & running.
You don't need to water quench the brass. I cool the brass under a fan just to make handling more comfortable.
You cannot use the colour of oxydation of the brass as a guide to temperature as 1066 said. Even the same make of brass can come out differently coloured if not all cleaned exactly the same way before annealing. Even a batch cleaned yesterday will colour up different to one done today.
I have Tempilaq but never use it now because when it is painted onto the outside surface of a case & heated in a flame that heats first before the brass & hence doesn't IMHO read true.
As previously stated the annealing process depends on both temperature & exposure time.
To set the gas annealer I run a test watching for the change in flame colour to yellow. I then note the time it appears & set the speed to give an exposure time just less so that no flame change is visible.
That has proved over thousands of cases of varying sizes processed to provide what I need. I.e. consistent suitable neck tension and at least double the case life. NB Cases usually fail due to primer hole issues before I get splitting.

Ian
.

The idea, I thought, was to paint a line on the INSIDE of the neck and then it will be a reliable indicator. It should just turn from blue to very dark blue (almost black)

I started doing this when I first assembled my annealing machine but found with repeated checks, that tempilaq was simply not required. Lights out, gas on centre of neck and watch for the neck just starting to turn dark cherry red. By the time it glows bright red it's far too hot. If it doesn't start glowing a dull cherry red, it's not hot enough. The timer is set to that for each batch and nothing more is needed.

Some argue that you time it so that the flame just starts turning yellow but this is not reliable since that yellow flame (an indicator of surface zinc burning off AFAIK) can start when the very thin section of the case mouth where you ream for deburring and chamfering starts glowing before the main case neck.

 

[fizzbangwhallop]

Fyi. I bought a pid off evilbay for sub 15 quid and an IP box from local electrical shop.
Your setup is way cleaner than mine...

Thanks for the nod on using an IP box.... thats just opened up a load of options, I've found a load on CEF and there are stores near me. I’ve been thinking about the enclosure for the PID and thought an el cheapo metal cased car battery charger might be a suitable donor......

My updated caseholder from a different angle....

 

[Milligan]

Here is mine. Too big a box but it was what they had in stock

 

[Sharpie]

These were the .20Prac case I salt annealed a couple of months ago using the Ballisticrecreations case holder in the Lee pot...... having heated the salt cautiously up to 530c I turned the pot down and annealed 'til the temperature reduced to 520c, then turned it back up to 530c etc etc. These cases were in the salt to a steady count of 4 and then into a jug of hot water on the floor well away from the pot.

View attachment 128352

Following on from that I've since made another case-holder with an adjustable deck-height to avoid messing with the level in the pot and the next step is to ad a PID to accurately control the Lee pot's temperature..... work in progress.

View attachment 128353

That dirty 7mm RemMag case is only in there for illustration........ I run my cases through an ultrasonic cleaner as a first step.

Fizz

Full marks for endeavour.

My guess is that the colour change induced by the process is due to an oxidising reaction with the molten salt and not indicative of much else. The potassium nitrate content (basis of black powder) particularly. I see that your results look quite variable.

PIDs aren't magic either, you can try their auto-tune, or for precise purposes set them up manually, which is quite a skill. Then you are relying on the little Lee pot with it's small volume of salt, to keep up with the energy that you extract every time you dunk a case into it. Faster, slower, one or two at a time, big cases, little ones, the salt doesn't get stirred around much, does the thermocouple reading correspond to that actually experienced by the case ?

Personally I don't fancy having a pot of molten salt with strong oxidising power anywhere near me, I'd rather take my chances with molten lead.

Then you need to wash off the salt residues afterwards and dry, at least I presume that you should.

As well as keeping the pot topped up with fresh salt mixture.

Spinning in a flame until dully glowing in the dark, or blackened soap, seems as good a way to me. The extent to which this is automated is your preference, and your throughput requirements. I suppose that once you have such a machine set up you can run the cases through before every reload, whether they need it or not. Remembering to re-calibrate every time you adjust the torch, unless you have a way of locking it down rather than just twiddling the knob until it looks about right.

Colour changes to the heat affected zone don't tell you anything, they are just a surface oxidation side-effect, that can give some clues as to which parts of the case you heated. If using a flame it also depends on whether you were in the reducing zone or the oxidising zone, or at the boundary between (the hottest part), and the gas that you used. Propane, butane, so-called MAPP (nowadays propylene).

MAPP gas - Wikipedia

en.wikipedia.org

Polish them up in a tumbler afterwards and you won't be able to see any difference with the body, brass doesn't change colour or display any other visible signs to confirm whether you have done a good consistent job, or not.