Salt Bath Annealing, Pro's and Con's.

[Robinhood]

I've got you now. I agree on the 1000 degrees. The zink will start to liquefy below that I think very close to 900. I am not worried about heat soaking that fast but over annealing is a concern. The guys I know are somewhere around 800 to 850.


I don't think the process is flawed. One test is to weigh it before and after. If heat soak is a concern, What I did was put some 450 below the annealing line. If 750 is the "anneal" temp for C2600 brass and it never breaks 450 at the body above the head my belief is it is OK.Do you agree?

As always you have a keen eye for shortcomings.

[darkker]

I don't think the process is flawed. One test is to weigh it before and after. If heat soak is a concern, What I did was put some 450 below the annealing line. If 750 is the "anneal" temp for C2600 brass and it never breaks 450 at the body above the head my belief is it is OK.Do you agree?

As always you have a keen eye for shortcomings.


I don't think the fundamental process is any concern, no; only the temps being used.
I know that Lapua openly admits to using Olin alloy C260, everyone else seems to hold that in the realm of Super Secret Squirrel Sh....:rolleyes:

As originally spec'd, C260 was a certain mix, with a tensile strength spec'd at 70-75,000psi. Which is another reason to not be to enamored with "signs" of case stretch for SAAMI MAP as reliable, but that's a side note. If someone else uses a different alloy, or tensile rating, it may not translate as well as hoped. But yes, 450 at the body wouldn't bother me personally either.

Cheers

[big honkin jeep]

I got injured at work, forklift driver carelessly tried to load 1300 lbs of shingles into a pickup truck while I was bent over the tailgate pulling out a pallet the customer was returning. Customer was paying attention and screamed at the driver who stopped just as he pinned me against the tailgate. A couple more inches and I'd of been a goner. Went to the hospital to get checked out, and of course, caught the flu bug since the hospital is full up with flu cases, and my flu shot wasn't much good.

Just wasn't my day :crutch:

Dangitman I feel for you,
37 years after a forklift accident that almost cost me a leg, (run over in the back of a 48' trailer) I still give them a wide berth.
I hope you get mended quickly and completely.

[Texas10]

Shot some pic today as I annealed 308 and 6br brass. I'll get them up as soon as I can remember how to resize and post.

[PhilC]

I got that the whole case goes in a roughly 900 - 1,000 degree bath for 4-5 seconds for the process used to anneal.
No it does not, only the neck/shoulder region goes in the solution. The case is set on a holder that limits how much of the neck/shoulder region can be immersed. Check the second linked video, this one (https://www.youtube.com/watch?v=qaHGwrKzQYY&feature=youtu.be), the guy is using his fingers to remove the brass and drop in his dunk bowl. No way he'd be doing that if the case head was 450° let alone 900°. Skip to 22:16 to bypass his wordy prelude and just watch the process.

At 23:58 you can see the depth line on the shoulder of the .223 case. He shows a clearer indication with some "dirty" 300WM brass at 25:28. Tempilaq on the case just above the holder would eliminate any question of overheating.

[darkker]

That's excellent, thank you for the link.

[Texas10]

Just to clarify a bit, the 3rd and 4th photos are of the baffle/case holder. The second of the two show the neck holder that suspends the brass to a fixed depth in the salt bath, which is adjusted to submerge only the portion you want. I prefer the salt to cover the neck and about half the shoulder.

The 1000 degree temp really does nothing to the composition of the brass in the short time it's heated. Annealing is dependent upon time at temperature, the hotter the temp, the faster the annealing process is completed. I found this process is actually faster then using a propane torch which burns at 3600*F (1980* C)
and unlikely to overheat the brass because it heats evenly inside and out.

If you like, you can google "salt bath annealing cartridge brass" to find some good video's, or go directly to the BallisticRecreations website link provided.

Good luck and good shooting.

[Savage170]

DARKKER:

"As originally spec'd, C260 was a certain mix, with a tensile strength spec'd at 70-75,000psi. ..... If someone else uses a different alloy, or tensile rating, it may not translate as well as hoped."


I analyzed some cases for my brother a few months ago, I thought Lapua was in here, it's not, but for what the info is worth here it is, I hope it contributes to the thread. This data is listed as MFG and Caliber, I do not know if the recipe translates across all calibers for a given MFG. This data is for a specific case, for a specific caliber, from a specific MFG.

Industry Brass 260 aka “Cartridge Brass”
Comments: Cartridge Brass
Copper, Cu 68.5 - 71.5 %
Zinc, Zn 28.5 - 31.5 %
Iron, Fe <= 0.050 %
Lead, Pb <= 0.070 %
Other, total <= 0.15 %

Federal 6.5 Creedmor
Comments: Brass 260
Copper 70.03%
Zinc 29.81%
Manganese .01%
Iron .05%
Tin .01%

Remington 280 Remington
Comments: Brass 260
Copper 71.55%
Zinc 28.25%
Aluminum .12%
Phosphorous .01%
Iron .04%
Tin .03%

Winchester .243 Win
Comments: Brass 260
Copper 69.99%
Zinc 29.52%
Aluminum .29%
Iron .06%
Nickle .03%
Tin .11%


Starline 7MM-08
Comments: 443
Copper 73.67%
Zinc 26.23%
Tin .04%
Iron .04%
Manganese .01%
Phosphorous .01%

[Robinhood]

I nuked some at work on time. I have the data sheet I documented the stuff on somewhere around here. If you are working with a recently calibrated gun with a new sensor(from what I am told) they are crazy accurate. I have had some cutting fluids cause them too lie before though so everything has to be clean. Thanks for posting that. Check the blue box and the gold box Lapua brass that everyone claims is the same.

[Texas10]

To read results of some definitive testing, see this test report under the home tab. http://www.savageshooters.com/content.php?405-The-Realities-of-Case-Annealing

Bottom line: Anneal every time for consistent neck tension, and use a bushing (or mandrel) die. Conventional dies using an expander ball will overwork even the freshly annealed brass. Neck tension is a function of brass harness and interference fit and will affect shot to shot consistency accordingly.

Annealing is complete at 1000*F for a few seconds, and those temps will not change zinc contents of brass.

The tests were conducted with an induction type annealer, where annealing temps are tightly controlled. There was no mention of salt emersion type annealing.

YMMV.

[Robinhood]

I wasn't concerned about ruining brass, but I understood that was Darkkers thinking. If you were loosing Zink, your salt would have a dark layer on the bottom of the hardened plug.

This was a great post Texas. Thanks for taking the time for the review. It helped push me over the edge on getting one.

[Shooter0302]

Great info, where do you get the two disks ? and is there a bottom disk for small cases like 223's and a large one for 308 size cases ??

[Robinhood]

Great info, where do you get the two disks ? and is there a bottom disk for small cases like 223's and a large one for 308 size cases ??


http://ballisticrecreations.ca/salt_home/salt-bath-annealing-kit-rev/

[PhilC]

Just wanted to post that some kits have been available. I was able to order one yesterday but see they're out of stock this morning. For any looking to get one of Gary's kits, keep checking back as he's working on increased supply.

[Texas10]

Update: You can probably see in the photos that the aluminum parts of the melter pot really don't do well around salt, and when I went to use it several days ago, it was just a mess of corrosion. So I ordered a new pot on Amazon and painted it with high temp paint before putting it to use.

With everything ready I plugged it in and a couple minutes later heard a pop and saw sparks. The heating element had failed, and took the thermostat with it. I ordered another Lee Melter pot and had it in my hands the next day and after painting it, plugged it in and.....same result.

So I called Lee and found out that they had a bad batch of heater elements and offered free replacement.

With new parts in hand several days later, I put it back in service and it worked fine.

Lee customer service was tops, with parts to fix one pot and another new pot on the way, can't beat that!

So if you're just getting into this form of annealing and using the Lee Melter Pot for the first time, plug it in and just watch it for 10 to 20 minutes without touching it. Read that again, without touching it. And if the heater fails, simply call Lee and they'll take good care of you.

[PhilC]

Thanks for that head's up T10, the last part I needed to build a PID controller arrived Monday so I can finally start assembly. My Lee pot delivered in May is still sitting in the box unopened, hope I don't have same problem, but now know what I need to do if the heater fails.

[Texas10]

I would be interested in reading your experience with PID controller when you get it working, Phil.

And since you're going to disassemble the unit it wire for the PID, I highly recommend the high temp paint on all aluminum parts. Also a high temp silicon seal on the lower pot cap to keep salt from seeping under the cap.

Please write back with your PID building experience and overall satisfaction with it.

One other caution when using the Ballistics Recreations thermocouple is be sure you don't twist the plug end. The wires are exposed inside the plug and when twisted they'll short and you'll get erroneous temp readings that will throw your PID into conniptions.

[PhilC]

Thanks for the head's up and will do.

The way I'm going eliminates the need to disassemble the pot for the PID controller, I'm also not using the BC thermocouple. Got the idea from this l o n g video - https://www.youtube.com/watch?v=AgixJeF0vEU

Longest wait was for the project box, apparently the company had to run a new batch, even the 800C thermocouple from China arrived sooner. Have some ideas for modifications over the one in the video, so will detail them when I do the build.

[Texas10]

I wasn't concerned about ruining brass, but I understood that was Darkkers thinking. If you were loosing Zink, your salt would have a dark layer on the bottom of the hardened plug.

This was a great post Texas. Thanks for taking the time for the review. It helped push me over the edge on getting one.

You're welcome, RH. Having lots of fun and decided to share my experiences.

I get the black layer on the bottom of the hardened salt plug, but I'm pretty sure it's not zinc, but blueing being stripped off each time I tap it out after cooling. I noticed that the steel pot was very nicely blued just like a new barrel after the first use. Tapping out the cooled salt plug reveals bare steel spots in the bottom of the pot and a blackened bottom before annealing any brass.

[Texas10]

Another update: I am finding that the amount of time in the 1000 degree salt bath does make a difference on the neck tension when seating a bullet. My process has always been to size the brass then anneal to get the most consistent neck tension and I'm finding that emersion time does make a difference in seating effort. Only a few seconds seem to matter, so I'm trying to keep careful track of time at temp. Longer seems to be better and the difference shows up on the target.

As always, YMMV.