Proper annealing temp?

[6.5grendel]

I've never annealed but I have been wanting to start or at least give it a try. I've been reading up on the different methods of annealing such as handheld torch while spinning case, automated machine, and salt bath. A thread I recently read talked about salt bath annealing using a Lee melting pot and a fixture from Ballistic Recreations to hold the cases in the pot. It seems like a pretty inexpensive and easy way to get repeatable results. The thing that has me confused is that it says not to heat the salts above 590F or you get toxic fumes. Everything else I have read says to anneal at temps of 700-750F. Does salt bath annealing get hot enough to properly anneal cases? If it does, then what is the proper miminum temp for annealing?

 

[Tech0214]

“Brass is annealed by heating it to a certain temperature for a certain amount of time. The higher the annealing temperature, the shorter the time required to anneal. The grain structure of the brass begins to change - indicating the start of annealing - at just under 500 degrees Fahrenheit. At 600 degrees F, brass will anneal in one hour. At 800 degrees F, brass will take only a few seconds to anneal.” This is taken from an article in MassReloading.


From what I’ve found. This can be a touchy subject on the this forum.

 

[spclark]

This can be a touchy subject on the this forum.

Touchy?

Here?

Surely you jest.

Problem is we all can’t settle on exactly what ‘annealing’ actually means, let alone arrive at a consistent protocol as to how to go about either describing it or achieving it.

Cartridge brass to be reloaded doesn’t need to be fully annealed before further processing. It’s not like we’re making new cases from raw brass stock.

When I set upon this path (ironically when I was shooting 6.5 Grendel too, abandoned years ago) I started with electric drill + deep socket + propane torch method ‘cause I already had it all laying about.

Worked fine - at least for my needs - after I burned a few cases getting things figured out.

My goal was to achieve consistent shoulder movement when re-sizing cases. Without ‘annealing’ I was seeing anywhere from 0.00” to 0.008” movement in cases fired maybe three times.

Running case shoulders in a torch flame for 7-8 seconds changed that to 0.002”-0.003” immediately.

So I moved on to other cartridges like 308WIN, 6HAGAR, 6.5WSSM briefly. Each needed a different deep socket, maybe a small change in dwell time in the torch flame, but it works.

I moved on to an MRB Annealer a few years ago after my back started hinting it didn’t appreciate the posture I kept while sitting holding that drill.

Dwell’s about 4-6 seconds now, cases behave exactly as when the cheaper method (hardware-wise) was used.

I know some favor salt-bath annealing, but if the salt being used is hazardous above 600F & that means cases have to sit in it - upside down - for awhile at a slightly lower temp to get decent “stress relief” (my preference for terminology) I’d think it’d both take too long for a bunch (300+ cases, my average batch) as well as pose risks for both case walls and my working environment due to fumes.

Let the flaming begin!! (Pun fully intended!)

 

[6.5grendel]

I also read that exact article. That was making me wonder how the salt bath works in only a few seconds if it is around 500-550F. Also, most of what I read on using a torch recrecommends using 750F tempilaq to get proper temps which goes right along with what that article suggests. I imagine there is a broad temp range that works when annealing but 500-750 seems like a huge difference. I just don't want to waste the money on a salt bath setup if i would be better of using a propane torch. I apologize if this is a touchy subject. I didnt mean to open a can of worms.

 

[spclark]

The points to remember:

You’re working to achieve consistency in neck sizing, neck tension, shoulder set-back, case life;

You do not want to affect brass strength anywhere below 3/4 of the case length below the shoulders - by that I mean you’re focusing your efforts to a point just above a point slightly behind the case wall / shoulder junction.

Dimensions of cases (wall thickness, case diameter and length) vary so much no specific number can work for all of ‘em, either for how long to dwell in the heat source or for where that point on the case sides is exactly. For 308WIN I try to avoid heating much below about 1/4”-3/8” below shoulders. 6HAGAR about 1/4”.

Brass necks & shoulders will likely be ruined for our purposes if heated to where they glow bright red in a room lit well enough to work comfortably. If you prefer sitting in the dark (I don’t) and get a dim, dull red glow, that’s OK. You won’t see that point easily if you can see well enough to work at other tasks.

I focus the inner blue flame of a single propane torch right at the case shoulders. Adjusted so that inner cone is ~ 3/4 - 7/8” long, the outer cone is about 1-1/2” long, much paler blue. Putting the inner cone tip ~ 1/4” off shoulders, case necks and sides get hotter than shoulders by conduction only.

Templaq is useful when you first start out if you need confidence in your set-up. I used it for awhile but haven’t bothered after the first few attempts. It’s just Not That Hard an endeavor if you pay attention to how your brass reacts to what you’ve done to it.

If air-cooling, a fan helps move air over processed brass for cooling. I let my brass fall into a NECO-type brass sieve fir cooling. Running 100 at a time, the sieve fills rathet nicely but as cases accumulate they take longer to cool if I don’t use a small camping-type fan to assist cooling. I’ve never had issues with loss of case wall strength since I started ‘stress-relieving’ cases with heat.

 

[Ccrider]

I think you have it wrong. Do not heat above 590c.

 

[spclark]

I think you have it wrong. Do not heat above 590c.

You may be spot on there! 590C = 1,094F! Lead (Pb) melts at 622F; some advocate using that for annealing, but heated beyond melting temps the vapors too are toxic.

Might I ask, just what ‘salt’ is recommended for this process?

There are many kinds that decompose at elevated temps. You do NOT want to be casually messing about with anything ending in cyanide...

 

[6.5grendel]

Ccrider, you are right! I went back and read the thread and site on salt bath annealing again and everything is in Celsius. Everything I read on annealing with a torch referred to Fahrenheit. Sorry for the useless thread. I obviously need to pay more attention to the details.

spclark, you are correct. 590C would be 1,094F which is well above th 750F. The salt that I have read about that is recommended is heat treating salt. I believe a blend of potassium nitrate and sodium nitrite. Ballistic Recreations sells the special salt. Hightemptools.com also sells heat treating salts. And yes, if those salts are heated beyond 590C or 1,094F they put off toxic vapors.

I think I'm going to give it a try now that I have my confusion straightened out. Seems like an easy process with a very low cost. Around $45 for the Lee melting pot and $10 for the salts. Thank you everyone for the help.

 

[spclark]

https://ballisticrecreations.ca/salt_home/salt-rev/

Good that they warn you about overheating this stuff.

Potassium Nitrate is one of the three ingredients used for making black powder. You don’t want organics in it when it’s being used or stored.

 

[jepp2]

Everything else I have read says to anneal at temps of 700-750F

Not everything. Most of what you will read will suggest getting the brass to 750°, but more recently it was revealed that is actually stress relieving, not annealing. To actually anneal you need to get the brass to a dull red in a darkened room. That is around 1050°. The difference is the extremely short dwell time at temperature and better information now available from AMP.

I made the conversion recently and was kind of full circle for me. As when I first started annealing in the early 70's the technique was brass in a pan of water half way up the case and heating the case neck until dull red in the darkened room.

 

[TC260]

It's all annealing. "Stress relieving" as it's called here is just recovery annealing as opposed to full annealing. Materials textbooks explain how it works.

 

[varget204]

If you look at most recognized annealing sites,most suggest 750 degree Tempilaq,Simple,it's a reddish brown color,brush it on inside of neck,when heat gets to 750 it turns clear,only have to Tempilaq,3-5 cases to determine how many seconds b4 it turns clear.Once u know time your good to go,a Simple propane torch will work,although you can buy them that are advertised for annealing; THe Woodchuck Den sells Propane Tip called Ring of Fire,heats circumference of neck at once

 

[SAILOR]

if anyone wants a Woodchuck Den Ring of fire i have one for 40$ shipped.

 

[Willie]

Every time I read one of these threads, I get down on my knees, so thankful for the AMP machine.

 

[Murray Brook]

I purchased the salt bath set up from Ballistic Rec about 3 months ago. I find it work really good only you have to always keep in mind you are working with a very hot liquid. Protective clothing and eye protection should be a must. But all in all it is very straight forward.

 

[Texas10]

When the temp controller on my Lee pot began acting up, my salt pot got up to 1125 F according to my temp gage, but there was no discernible change in the salt bath. I unplugged the pot as soon as I realized it'd gone so high, having read the same warning about hazardous fumes, but I detected nothing different.

That may be due to the combination of salts used by Ballistic Recreations, but I can't say for sure.

 

[6.5grendel]

Texas10, do you use the Ballistic Recreations salt or a different salt? Is there any other place to get the salt from? Ballistic Recreations is out of stock and Hightemptools wants $24 just for shipping.

 

[muleman69]

If you look at most recognized annealing sites,most suggest 750 degree Tempilaq,Simple,it's a reddish brown color,brush it on inside of neck,when heat gets to 750 it turns clear,only have to Tempilaq,3-5 cases to determine how many seconds b4 it turns clear.Once u know time your good to go,a Simple propane torch will work,although you can buy them that are advertised for annealing; THe Woodchuck Den sells Propane Tip called Ring of Fire,heats circumference of neck at once

When I use tempilaq it turns from green to black, what have I done wrong?

 

[PatMiles]

When I use tempilaq it turns from green to black, what have I done wrong?

Does it actually turn black or clear as it should, showing the color of the carbon deposit (black) inside the neck area?

 

[muleman69]

Does it actually turn black or clear as it should, showing the color of the carbon deposit (black) inside the neck area?

It shows a tarnished look whether inside or out?