A question about anealing?

Mram10us

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That is not true. They have done studies using 1000°F molten lead It took a piece the thickness and size of a cae neck fully submerged 19 seconds to reach equal temp to the bath. Actually they used it heated from 650 in steps up to 1200. The higher the temp the shorter the time to reach equalibrium.


Not directed at anyone here but a genrral observation. People want salt bath to be the answer as its cheap its easy to do. It addresses the heat consistency issues of propane torch. But it just does not work as people think. It does do some stress relief. The beginning part of recovery phase of annealing. But there is no way it can work. 3/4 of the case is acting as a huge heat sink pulling heat off the neck. It takes a fully submerged piece so no cooling or heat sink effect 19 second. Thats way too long. A neck submerged case would take much longer.

The one way it might work is switching out the 50/50 blend of nitrate based salts for a 50/50 blend of chloride based salts. This would allow 1600°F.

Consider for a second that the flame on a propane torch, the outer part of the light blue tip where it almost goes clear, is around 2000°F. That is why it works so effectively. It overwhelms the thermal conductivity ability of the brass. Heats way fast than it can absorb.

We have to have sonething that heats super fast that it overcomes/overwhelms the thermal conductivity of brass which is one of the highest.

Low temp; molten salt bath does improve the cases and will make them last longer but they are not annealed to a factory state nor to a ideal hardness. I also think they will continue to get harder just at a reduced rate. So its not a complete failure just under performing.

What we are actually doing or our goal is not to just anneal the case neck; that has no frame or specificity. Its also why there is so much confusion because people throw around terms that are not correct or specific trying to describ things.

What we are doing same as the factory on the final neck annealing is known as "Temper Annealing" or "Annealing Temper" Ior Annealing to Temper" the last is most correctly descriptive. We are annealing to a specific hardness range , state also known as temper. There is an entire standardized list of anneal temper states in various industries.

I have wanted to lay out all the data with the carious referenced data studies lab reports etc but its a immense amount of work. I felt I would likely get frustrated when people tried to refute it with nothing more than "it works for me" or similar without any real tech support for thier position.

The AMP guys knew this before they ever bothered to test it as they have to have more time into annealing research than me. Otherwise I very much doubt they would have reported the results. The results where the shoulder lost more piint in hardness from its starting point than the neck also maje sense on the long soak time and is fully explained in the annealing science of work hardened copper alloys.

Hey I can be wrong but some of this but the studies and technical articles from metalugists that are suppose to be experts in this field support it.

Again salt bath does have a positive effect but its a small one. Believe me I wish it worked just as well. I would not be spending the hours tweaking things and studying schematics to build an induction annealer. What you really pay for with AMP is testing that developed the program to test and chose the correct anneal time or there manual testing to give the correct time.

IMO, that's where the real critical part is. Knowing that [email protected]/mass formula for each case.
I would like to see the test info from the lead example. Other studies have shown it takes 5-8 seconds at 500c to anneal a brass neck (see https://ballisticrecreations.ca/salt_home/annealing-knowledge-centre/annealing-lit-review/)
Questions I have always had, but haven't taken the time to figure out:
1. How long does it take heat to transfer from both sides of the neck thru the entire .015" (for example)?
2. How is the zinc affected since its melting point is <800f?

It seems that SBA gets us to the temps needed to anneal the brass without as much error as a flame. Since we are looking for consistency, even a partial annealing (assuming it doesn't fully anneal) would still be what we are looking for.

All this to say, I'm not sure how Hot Lead Annealing cannot somehow anneal the brass when a temp/time is what we are after. Simple mechanical or chemical engineering tables should allow us to compute the time it takes 500c heat to transfer thru the neck. Then further help us compute how much time it takes to transfer the heat up the shoulder and case body.
 
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Mram10us

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I have a very old lee pot I have replaced the cord on long ago.

Someone with a newer one. What gauge wire does the power cord appear to be made of? 16g 14g 12g?

What setting are you finding it needs to be set on average to keep salt at 500°C?
My old pot needed to be at 6 to get up to 500c, then set on 7-8 to stay there when annealing rum size cases every 7 seconds.
My new pot heats up at 4 and holds at 6.
 

bushmotornv

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I have a very old lee pot I have replaced the cord on long ago.

Someone with a newer one. What gauge wire does the power cord appear to be made of? 16g 14g 12g?

What setting are you finding it needs to be set on average to keep salt at 500°C?
My new pot seems to be 14g. When I first fired up my salt bath using stock pot control, I maintained 500°C between 6-7.
 

bushmotornv

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Exactly. That is what makes the salt bath so attractive I also fully agree it does improve things and if you have it use it. I am not against salt baths. On contrary I am trying to see if with changes they can turn out better end result.

Where they really shined for people is in its comparison to a propane torch setup in terms of reducing unknowns. There was always that unknown of what temp were you actually applying to the case neck. Move it just a tig and it was a different temp....but what temp?? There was nonscale standard even using tempilaq. The salt bath instanty addressed this with high accuracy and consistency of temp being applied.

I do not seriously think anyone gave thought to the difference between the temp of the heat source vs the ideal temp we want the case neck brads to reach and the heat sink effects of the rest of the case in terms of how it effected heating the neck to a certain temp. There in is the issue.

We have been using both low and high temp molten salt baths in blacksmithing for heat treat annealing normalizing for some time now. It offers other benefits in this area vs brass case annealing. But it has many of the same benefits as well. Low cost. Precise control of temperature and its even and consistent in its application to the work piece.

When I went looking for support and the technical reasons for results vs other heat source annealing, frankly it was a PITA. Most annealing technical papers use ovens as they are not doing differential annealing. The info is buried in pages and pages of other techincal data etc. You had to read and wade thru it all to find the nugget you were after.

That brings up another point. I said it was annealing to temper but really its "Differential Annealing to Temper" as we are only doing that small section and decreasing to no effect as we go down the shoulder to body.

If you look at the crystaline structure of the brass in some of the microscopic images you see the are long polygonal shapes with sharp corners edges etc. When we expand the elongate but also separate from each other. Those edges lock into each other holding the tension of force. Compress them and they are being forced pressed together.

When you heat them even if its below the typical annealing temp ranges say 350-500°F. It can soften but also expand n swell those interlocking points of stress It can allow them to slip. The crystals do not change shape etc but small amount of tension. In the case of the necks release small amounts along the lateral sides and those slip joints.

For me it really helps when I can visualize what's happening.

Fact id all those studies and tech papers that speak of annealing for minutes even hours are not bogus. Obviously they are peer reviewed and were done in labs by metallurgists. At the same time we have tons of real world proof of how fast neck annealing happens using torch etc. I knew both were true so I setout to understand how. That was some time ago.

But a reloader can not be expected to spend weeks reading over studies, tech manuals, ref books, etc Buying micro vicker hardness testers etc. Outside a few geeks nuts like myself we need a cookie cutter setup Hence why salt bath was/is so exciting.

I am trying to see if I can make the high temp chloride base salts work in a lee pot or some other equally low cost setup. But it takes actually testing the hardness and looking at the structure which means paying to send it off to a lab. So its a personal nvestment for the communal benefit. Which I am good with.

Same goes for induction annealing. Building an induction setup is not costly at all. Its tuning and timer setup that is the bugger and generally cocks thing up well and good along the way.

Then we are left as we are with all of these annealers with figuring out ideal time for a given case neck mass. That will always be the thorn. Its what really was the major benefit and worth the cost of the AMP unit. IMO its where a large % of the cost overhead is tied up as its manpower heavy. If you looked at profit counting only cost of the annealer itself it would be very healthy indeed. But out in all the r&d and constant testing for proper time to reach given temper. Now that adds up to some $$. Of course it gets spread over all unit sales So in the veginning it was very much a negative return. But wity the increased vol.......

Now with the built in info and database it no longer seems the case but that has to be backed up by real testing. I want to research further to see exactly how the process on the AMP works for case testing. More out of my own curiousity. Its also protected by patent Im sure. Regardless my own *Rule 1 Violation*s would prevent me from any shenanigans.

As a community we can establish times for a given standard with trial and error. Once we have that and the relationship it will allow us to build a sort of data base. But we need a standard when it comes to induction power voltage and coil design.

I am just a curious guy that likes to work stuff like this out. I find it like others do puzzles and brain teasers.

Without a doubt I think induction is the most precise way to anneal. But I still want to give the high temp salt a go to see how close I can get. The only real downside is safety. I have suffered full thickness burns on parts of my body from past employment/career.. So I know better than most what molten liquid does to flesh.

.
I'm not saying that the salt bath is completely safe,but the case holder covers most of the pot. Only the cartridge ports are open to the top. The only real danger is the carry off salt dripping onto whatever surface is above your water pail. As far as quality of the anneal, I annealed old military 06 cases with an unknown number of firings on them. The discoloration(which we all know varies by manuf) can be as dark as you like,per time in the bath. 10 seconds per case made a tremendous difference in the sizing of the cases. And the head never got hot enough that you couldn't handle the case with bare fingers. Perfect...maybe not...but it is easy to maintain consistency of the process. From my experience, cases that have been cleaned with ultrasound(I like the Hornady solution) anneal better because the carbon residue has been removed from the inside of the case. And polished cases do not carry off as much salt. And FWIW,you can over anneal a case by running oo high a bath temp,and too log a soak time. Ask me how i know this.Just my humble observations after using the SBA method.
 

Mram10us

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To avoid dripping salt, I started tapping the cases on the case holder after pulling them from the bath. The extra goes back into the pot and less filling it with extra salt. Nothing cosmic, but it seems to work well for me. Great to hear other guys experiences with SBA. It sure is noticeable on the comparator. Easily .003" difference between twice fired RUM and annealing each time. MUCH more repeatable when I compare each case after FL sizing.
 

tim_w

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My new pot seems to be 14g. When I first fired up my salt bath using stock pot control, I maintained 500°C between 6-7.
Thanks.

I am trying to setup a hot plate or all in one that has 1000watts. I had seen one new one in a store and it looked like it could have been 16g. So 14g is good to know.

I know people have gotten the lead molten tobwhere it had to be 1300-1400. I am to get to something where a 300wm case takes around 5 sec. I think that will take 1500°F

The thing with temp is its not linear for time. When you reach a point time becones disproportionately shorter with temp increase. With such small volumes chloride salts are not a big deal in terms of fumes. Just need modreate air flow.

At the same time I have parts ordered to work on building an induction annealer. The issue is ideally we want to run it on 120 not 240. That means we are looking at max 1400w @ 48v which will be fine. That with a water cooler radiator setup will give 100% duty cycle. Then I need to work a case feeder. A basic one can just have a push button to start programed cycle. Manual seat and remove case.
 

BigBullBob

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GLTaylor

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Just paint a single stripe from the case mouth to well past the shoulder of the case. When the brass reaches the target temp it will change from color to clear/dark. Time this. That gives you the target time to immerse the brass. Once you know the number of seconds it takes for your case, duplicate this time for each case going forward.
 

nksmfamjp

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Where do you apply the Tempelaq?
Inside the neck. You are trying to get a minimum at the farthest point of conduction, if that makes sense.

You can put low temp tempilaq on the outside near the base, but I put 3 long strips base to mouth. Then I make sure the target temp melts in the neck and just below the shoulder..
 

Mram10us

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Thanks.

I am trying to setup a hot plate or all in one that has 1000watts. I had seen one new one in a store and it looked like it could have been 16g. So 14g is good to know.

I know people have gotten the lead molten tobwhere it had to be 1300-1400. I am to get to something where a 300wm case takes around 5 sec. I think that will take 1500°F

The thing with temp is its not linear for time. When you reach a point time becones disproportionately shorter with temp increase. With such small volumes chloride salts are not a big deal in terms of fumes. Just need modreate air flow.

At the same time I have parts ordered to work on building an induction annealer. The issue is ideally we want to run it on 120 not 240. That means we are looking at max 1400w @ 48v which will be fine. That with a water cooler radiator setup will give 100% duty cycle. Then I need to work a case feeder. A basic one can just have a push button to start programed cycle. Manual seat and remove case.
Tim, curious how you decided on 1500f. Studies have shown brass can be annealed at 600 for an hour (ugh) or 800f for 5-8 seconds. Definitely not linear, as you stated. What not try 900-1000 for a quick dip of 3-5 seconds? curious to see your results!
 

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