Salt Bath Annealing

[Mikecr]

They're being critical in the sense that the exact kind of annealing Mike is looking for isn't what they're looking for.

I agree, and I'm sure their machine could be programmed to provide what I want. What anyone wants.
But I already have exactly what I want, for decades now, with dip annealing.

That's what I'm defending, against what I see as a smear campaign against main competition.

 

[WildRose]

Nothing happens with brass until passing 450degF. For shoulder depths I hold cases by hand at the rims when I dip, and there is no heat building at the case head to matter. Even with short 6BR length cases.

I was just agreeing with your final point in that post. No argument from me on any of it.

Now if you wanted to full anneal, then temperatures and timings are all different. AMP is right about that, it's nothing new.

But that has never been what I want with cartridge brass.

 

[misser]

it follows that a shooter who regularly neck anneals cases in the range of 500°-550°C for five seconds can expect complete mitigation of cracking without affecting the fine-grained factory microstructure of the brass.

– Annealing temperatures of 600°C and greater begin to produce substantial metallurgical changes in the material, simultaneously resulting in reduced hardness, increased recrystallization, and grain growth of the material. G. Chambers, Ballistic Recreations

 

[Mikecr]

You can reach 900 or 1000degF with a dip, pot knob maxed. That's about it, and you shouldn't want to go higher.

 

[QuietTexan]

Call me crazy but anytime your method or product is being criticized by your competitors I'm always going to be at least a bit skeptical.

And after listing cons of salt bath, they say this:

What is the point of taking on all that risk, when the results are so poor? There are several ways to achieve correct annealing. Molten salt bath "annealing" isn't one of them. For those reloaders considering getting started on annealing, and who are on a budget, we would recommend a gas flame-based option.

I don't buy into the notion that AMP is being overly critical of the salt bath method. They seemed to rationally lay out how one processes doesn't achieve their goals, and offered a viable alternative to their product to achieve that goal.

What they didn't do was a test running thinner brass or run that same Lapua brass through the process for 9-11 seconds which seems to be the magic point based on what I've been able to find.

They did do salt bath dips at 8 seconds and 20 seconds. The results from that is the core of their point regarding salt bath annealing in bottleneck cases.

This is where we found a significant anomaly. While the neck region of the cases when measured showed no hardness indications below 120HV, it was observed that extended insertion in the salt bath caused the shoulder and body to soften further.

You have to remember they're coming from the point that they want 100-120 HV in the shoulder AND NECK of the case. Salt bath doesn't get a bottleneck case neck to to 100HV. If 8 and 20 seconds didn't get it there, 11 seconds wouldn't either because the case isn't softening and re-hardening at different points in the dip, it's only getting progressively softer.

That's what I'm defending, against what I see as a smear campaign against main competition.

I don't think it's a smear campaign, just a bunch of loud Chevy vs Ford supporters on the internet BS-ing and yelling over more meaningful technical discussion between people who know what's actually going on. We know that both work, in different ways, and neither is designed to meet all of the goals possible here.

I'll be the first to say that salt bath should reduce the split neck and shoulder problems that come with fireforming shoulders. Should also anneal to the point that split necks in general go away. Also seems a lot easier than flame annealing honestly. I've watched BB's video a half dozen times and flame isn't complicated at all, but and at the end of it I don't want to be that manually involved in the process to be watching for a color change or anything like that, I'd find a way to screw up the cases the same way I could crack an anvil.

 

[WildRose]

And after listing cons of salt bath, they say this:

I don't buy into the notion that AMP is being overly critical of the salt bath method. They seemed to rationally lay out how one processes doesn't achieve their goals, and offered a viable alternative to their product to achieve that goal.



They did do salt bath dips at 8 seconds and 20 seconds. The results from that is the core of their point regarding salt bath annealing in bottleneck cases.

You have to remember they're coming from the point that they want 100-120 HV in the shoulder AND NECK of the case. Salt bath doesn't get a bottleneck case neck to to 100HV. If 8 and 20 seconds didn't get it there, 11 seconds wouldn't either because the case isn't softening and re-hardening at different points in the dip, it's only getting progressively softer.


I don't think it's a smear campaign, just a bunch of loud Chevy vs Ford supporters on the internet BS-ing and yelling over more meaningful technical discussion between people who know what's actually going on. We know that both work, in different ways, and neither is designed to meet all of the goals possible here.

How hot does brass need to be heated up to in order for it to be properly annealed?

 

[QuietTexan]

How hot does brass need to be heated up to in order for it to be properly annealed?

Partially or fully?

Somewhere between 500*F and 1000*F for somewhere between 2 and 20 seconds. Can be accomplished with flame, induction heating, molten lead, molten salt, or if you shop at Cabela's by firing in the chamber

 

[WildRose]

Partially or fully?

Somewhere between 500*C and 1000*C for somewhere between 2 and 20 seconds. Can be accomplished with flame, induction heating, molten lead, molten salt, or if you shop at Cabela's by firing in the chamber

The problem with that theory is that Zinc melts at just 420c, less than half the melting point of copper thus if we heat the brass to over 420c for any significant amount of time we risk cooking it off and having nothing left but copper and thus an unusable case.

So the key is heating the brass to probably no higher than 450c all the way through evenly so as to get the most effect.

I know for a fact that i've ruined brass in the past with the, "if some (red) is good, more is better theory" using a torch.

The key to making the salt bath work seems to me then is careful control of temperature not to exceed 450c, and figuring out the amount of time necessary to heat it up all the way through evenly without cooking off the zinc or otherwise damaging the brass.

If the pot is heated to 500-550c then it should be a fairly simple matter of figuring out just where that time constraint then is met.

From what I've gathered on the subject recently it seems as though we get maximum benefit by annealing our brass every 3-4 loadings IF we get it properly annealed each time so I'd really like to figure out exactly when that point is reached.

 

[Seabeeken]

Salt Bath Annealing - Does It Work? | Learn More | AMP

View the latest articles from AMP Annealing. Get tips and tricks from our R&D. Here we upload articles to provide your the best possible information on innovations in the annealing process.

www.ampannealing.com

 

[QuietTexan]

 

[QuietTexan]

The key to making the salt bath work seems to me then is careful control of temperature not to exceed 450c, and figuring out the amount of time necessary to heat it up all the way through evenly without cooking off the zinc or otherwise damaging the brass.

Sounds reasonable to me. The process has given positive results for a lot of guys so there's nothing to write off about it.

I think the entire argument goes back to AMP wants the neck at a certain hardness level, which induction and flame do but apparently salt bath does not. They supported the lack of neck hardness change with evidence. I don't have a reason to doubt them about that one point.

Who's to say the neck hardness is as critical as they think it is? I chose induction for other reasons, not specifically neck hardness. Maybe I should try salt bath and see if anything changes for me, I do try to keep an open mind on these things.

Not sure if I said it here or elsewhere, but salt bath might be ideal for fireforming cases to new shoulder dimensions specifically because it softens brass more in the shoulders than the neck, and that might change where brass in the case pulls from at it takes on it's new form.

 

[Mike Matteson]

Sounds reasonable to me. The process has given positive results for a lot of guys so there's nothing to write off about it.

I think the entire argument goes back to AMP wants the neck at a certain hardness level, which induction and flame do but apparently salt bath does not. They supported the lack of neck hardness change with evidence. I don't have a reason to doubt them about that one point.

Who's to say the neck hardness is as critical as they think it is? I chose induction for other reasons, not specifically neck hardness. Maybe I should try salt bath and see if anything changes for me, I do try to keep an open mind on these things.

Not sure if I said it here or elsewhere, but salt bath might be ideal for fireforming cases to new shoulder dimensions specifically because it softens brass more in the shoulders than the neck, and that might change where brass in the case pulls from at it takes on it's new form.

I have both salt and bench soruce. No comment presently. I did get an attachment to use propane from at 5 lbs tank with duel hoses. The little propance bottles isn't worth it. That item can be gotten @ amazon. I have read about all the different ways to anneal. When I started annealing was over 25yrs ago. The old case in the pie pan. A torch in hand. I will say that stop the necks from splitting. I don't feel that was the best way at this time by a long shot. I do feel that annealing after each shot is better than another way. (each your own) Your case is more consistent for releast. It's been my understanding the being consistent everytime creates better accuracy.
It really boils down to how much you want put into it. I do have a lot of respect for Mikecr too. There is several other here too that have a great amount of very good imput.