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Salt bath annealing?

Discussion in 'Handloading and Reloading' started by tcoz, Aug 3, 2017.

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  1. tcoz

    tcoz Member

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    I've either been living under a rock or this is so obscure that nobody uses it or it's "voodoo" annealing.
    Please comment, especially if you use this process. The 6+ minute video explains it....and it wasn't created on April 1.

    http://ballisticrecreations.ca/
     
  2. tcoz

    tcoz Member

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    But does it accomplish the same thing? Any downsides?
    I'm not about to try it but just satisfying my curiosity.
     
  3. barnbwt

    barnbwt member

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    That would be exceedingly dangerous for firearms applications, due to removing alloying agents that gave the case its strength in the first place (very much like decarberizing steel by exposing it to oxygen at high temperature to burn off the carbon & leave a softer mild iron behind). This is simply dunking the necks in a bath of non-reactive molten material to bring the metal above its critical temperature, I could see it being more consistent & controllable than a burner flame (more akin to molten-lead bath for drawing hardened steel parts a bit softer). I can also see any spec of water or combustible material inside the case causing a bubble of expanding gas to splash the hot salts around, same as with lead casting.

    Brass is a weird metal in that it easily soaks up a ton of different compounds that change its properties (ammonia being the most well known, since it causes rapid embrittlement that will split cases and explode case heads), so a dunk in high temperature salts being beneficial seems...unintuitive. I've been wrong before though, and it's possible/likely that these salts are totally inert with respect to brass cases.

    FWIW, the salts are nitrate-based, and not chloride-based, probably because the Chlorine would react with the Copper or Zinc (maybe; I think Sodium is still higher than Zinc in reactivity so maybe the Cl wouldn't hop off its tastier Na without additional persuasion like very high heat. NaCl and KCl are also at a higher melting point than you'd likely want for brass annealing)

    TCB
     
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  4. Orcon

    Orcon Member

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    You're right barnbwt, I made some false assumptions. This seems to be no different than the lead dipping method of annealing.
     
  5. Demi-human

    Demi-human Member

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    Somehow this seems more dangerous than a blow torch. I like it.
    Makes sense to me but is quite involved.
    I use my Annealeez to dry my brass after I clean them. Saves running the oven.:)
     
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  6. jmorris

    jmorris Member

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    Removing zinc from brass leaves copper, there is a reason brass is made from brass and not just copper. Too much heat will so the same thing and why you don't want to over anneal.

    If you have a pair of boots that are too stiff, you can make them soft by throwing them in a campfire and they will become softer, just not anymore useful.
     
  7. tcoz

    tcoz Member

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    So...from everybody's posts it looks like salt bath annealing might be based on some faulty science?
     
  8. hdwhit

    hdwhit Member

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    Go back and look.

    Once you ignore the posts premised on the erroneous assumption that the salts used being were chloride salts, the science is sound. The process would tend to be more tolerant of exposure time than using a hotter direct flame, but not by much. And the problem that the video downplays is the reactivity of the molten salts (not just to water, but many other substances commonly found in a garage or around a reloading bench).

    This will work and it can be done safely as was demonstrated in the video, but it will take care and attention.
     
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  9. Demi-human

    Demi-human Member

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    Not at all. It would work just fine. But if I over heat a case with a torch annealer I ruin a case. If one overheats the salt bath it produces a poisonous gas.

    To me it seems if one wanted to get a very precise anneal line one could use a torch and water, instead of hot salt.

    I have heard of using a lead bath too, but wouldn't it solder to the neck? Fire looks to be easier but this is a very interesting take on annealing.
     
  10. tcoz

    tcoz Member

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    Thanks for all of the great responses. I was just telling my wife that I've been reloading for twelve years and have barely scratched the surface of knowledge.
     
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  11. mdi

    mdi Member

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    Not knowing anything about the chemicals used nor how the brass is affected by the salt, I think this method would be more precise and safer than an open flame (or two). I wonder if one made a set up to be used with lead, using the same components (pot, thermometer, case holder) if the method would work? I would rather melt lead, with a higher "dangerous vapor" temperature than salts (best temp I could find for lead vaporization is around 1700 degrees F, where the vaporization for the salt is 590 degrees F). But that's a moot point anyway. The salt bath process looks promising...
     
  12. homatok

    homatok Member

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    Just for kicks:

    Annealing case necks by dipping them into molten lead that is held at about seven hundred degrees ‘F’ works well. Wheel weight alloy, which is approximately eighty nine parts lead, one part tin and ten parts antimony, melts at six hundred and nineteen degrees ‘F’ so you can safely set your lead alloy temperature at seven hundred degrees ‘F’. The use of a thermometer will take any guesswork out of the process. The reason for using lead for annealing is to keep the temperature low enough for proper uniform annealing, and that is simply not possible using the torch method. With a torch the case is often heated on one side more than the other, temperatures are not readily repeatable from case to case, and in falling over into the water, one side is quenched before the other.


    To minimize the likelihood of lead ‘soldering’ itself to the brass case it is best to use as close to pure lead as possible (although any lead alloy will work). Anneal your cases with the fired primers left in, as that forms an airlock that keeps lead away from the inside of the case. With respect to annealing cases using molten lead, basically you: set the thermostat on your pot at seven hundred to eight hundred degrees ‘F’ pick up each case by the head and dip the neck of the cases about a quarter-inch into some powdered graphite or light oil (vegetable oil is fine). The oil keeps lead from sticking to the brass but, any lead that does stick is easily removed by a quick twist in steel wool while the case is still hot. Shake off any excess oil, dip the neck, shoulder, and about a quarter-inch of the case body into the molten lead and just as you begin to feel an uncomfortable degree of heat in your fingertips, drop the case into water. If you hold the cases in some other way than with your bare fingers, leave them in the molten lead from eight to twelve, but not more than fifteen seconds. When the case is hot enough that the lead does not cling to it, it is annealed. Pull the case up out of the lead, tap on the side of the case to remove any bits of lead (if the lead is really sticking, the case isn't annealed!), then drop it mouth down (straight) into a container that is mostly full of ice water. Following the anneal, it would be wise to closely inspect the inside of the case both visually and with a bent paper clip just to make sure there are no lead drippings adhering to the inside the case.


    If you are left-handed, have the cases on the right side, the lead in the middle, and the ice water on the left. The cases go only one direction, to the left, and you use only one hand. If you are right handed, reverse the set-up. Because it only takes a few seconds per case, you can anneal hundreds of cases in an hour with this method. After the annealing process, remove the cases from the water, shake them out and use a piece of bronze wool to clean the annealed portion. This removes any residual lead and/or burned oil. Then, dry and tumble the cases to remove any traces of residual oil and they are ready to process.
     
  13. Demi-human

    Demi-human Member

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    Whew! That's it?:D
     
  14. Nature Boy

    Nature Boy Member

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    If I had to go through all of that to anneal I wouldn't anneal
     
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  15. someguy2800

    someguy2800 Member

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    I prefer safer pass times such is knife juggling or alligator wrestling
     
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  16. FROGO207

    FROGO207 Member

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    Well I anneal my brass in the lead pot just like homatoc describes. The only thing I do differently is I use a leather glove with most of the fingers cut off to keep my hand from overheating so much or getting burned. The fingers do need to be bare though or you will not be able to feel when the web of the brass starts to get hot.;)
     
  17. rayatphonix

    rayatphonix Member

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    I'm a member of a 6.5 Creedmoor forum. Several members there use this method with success. I've been using a torch for years and have ordered the hardware to try it. By the end of the month I'll be able to compare.
     
  18. Sunray

    Sunray Member

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    Please excuse my countryman. There's nothing to do in AB with their economy in the toilet. His idea is way more complicated and expensive($80 Cdn is currently $63.28US plus shipping and probably duty.) than it needs to be. A propane torch kit runs $17 in Home Depot.
     
  19. Saggins

    Saggins Member

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    Doing some reading in between loads of corn I came upon this today. My understanding is that you could also set the salt to 700-750f and it would still be molten. Couldn't you do the exact same method as the lead version, only with any residue or clean up being water soluble? And 750f, is juuust under 400C, I'd consider that well under the 590C vapor hazard
     
  20. Walkalong

    Walkalong Moderator Staff Member

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    That is pretty cool.
     
  21. Demi-human

    Demi-human Member

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    @rayatphonix , have you done any brass with your machine? I find this method more and more interesting.
     
  22. rayatphonix

    rayatphonix Member

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    I'm sorry to say I haven't. I've got the parts, but haven't had the time to put everything together. Hopefully I'll have time over the Thanksgiving holidays to complete.
     
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  23. Red Cent

    Red Cent Member

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    pid box wired.jpg
    This is a PID. This plugs into the wall and you plug in your lead pot to the PID. A thermocouple plugs into the PID and is inserted into the lead pot. For those of us who are anal about making the perfect bullet, it is important to maintain a constant temperature of lead melt.
    Looking into the salt bath, I found this (old) post, and the PID would work well in maintaining a safe temperature with the bath salt.
    I am unable to run and gun/SASS these days, so I have started shooting "long distance" (up to 300 yards so far) with the old rifles. Some may have seen a picture of the C Sharps in 38-55. I do not plan to resize at all so the annealing process is not necessary for me. But if something changes I would use the salt bath with the PID.
    PID AT4.jpg
    One can build a PID for about $50.00 or less unless you buy a "project box"
     
  24. Red Cent

    Red Cent Member

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    PS: The salt bath would not be more dangerous than the molten lead. Some of us who cast in the summer learn not to lean over the lead pot and let a drop of sweat hit an unfortunate spot. The salt bath will react to most of the same items that molten lead would react.
     
  25. rayatphonix

    rayatphonix Member

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    Demi, now I've used my salt bath annealer. I expect I've done between 600 and 800 pieces of brass. Compared to my propane annealer, I believe it's considerably more forgiving. A few observations:
    - different calibers require different times in the bath. I assumed 308 and Creedmoor would be the same. 308 takes a second or two more; 30-06 even more.
    - I have to rinse my brass afterwards, otherwise there's a salt residue. I never saw this mentioned anywhere.
    - keeping a steady temperature is not easy, when in use I've learned to expect about a 10 degree variation
    - I have not tried to do 223 or 204 brass yet, but I don't see a problem
    - I'm not sure how it will work on short cases, like 6.5 Grendel.

    Overall I like it and it was worth it. I don't shoot as many rounds as in the past, and it's easy to turn on and anneal the 20 cases I just shot.
     

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