Salt bath anealing

[Texas10]

http://www.hightemptools.com/Salts.html This is one place you could buy the salts. $4.50 per pound. I have heard the shipping is pretty spendy but probably a one time expense.

I plan at some point to try this but work has all my time. When I do I will post all the details.

I see they also sell a "low temperature salt" with a working range of 300 to 1000 F that would allow you to fine tune the stress relieving (annealing) process.

 

[Fotheringill]

The only thing I saw that was attractive was the cost of the components needed.

With all of the warning and the what happens IF's in the video, equipment failure, whether it is the pot, temperature gauge and whatever else can lead to catastrophic results to your house and yourself.

I will stick with my Annie and if I didn't have an Annie, I would go with an Annealeeze.

 

[Brians356]

Can this annealing process be done safely indoors.

If by "safely" you mean "risk-free", the answer is "No". Like deep frying a turkey, you would be prudent to do this outdoors.
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[Webster]

Has anyone tried salt bath anealing? Seen it on Facebook a while back and seems pretty legit. Guy took a lead melting pot and heated a mix of Potassium nitrate and sodium nitrate. They melt at about 900F and he simply dips the case mouth into the solution for 6 seconds. He made a neat little case holder so he can do 2 cases at a time and it's kind of a heat shield so not to burn hands. Has anyone messed with this. Is there any negatives to this? Would a different salt be better like table salt (easier to get). Tell me what you all think?

If there is any moisture in a case you could have a nasty explosion.

 

[Brians356]

If there is any moisture in a case you could have a nasty explosion.

Please elaborate.
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[Prose]

Putting water into a very hot pan causes it to boil vigorously. Putting water into extremely hot salt causes an explosive boil that will shoot superheated salt and steam out at high velocity (with a BANG). Kind of the opposite of what happens when you drop dry ice into water.

 

[Brians356]

Putting water into a very hot pan causes it to boil vigorously. Putting water into extremely hot salt causes an explosive boil that will shoot superheated salt and steam out at high velocity (with a BANG). Kind of the opposite of what happens when you drop dry ice into water.

That video shows dumping a large amount of molten salt into water, not anything like a tiny drop of water into a relatively large amount of molten salt. Not disputing anything, I'm just asking for a relevant citation. The assertion was that "any moisture" could cause an explosion. That's pretty dire.
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[Prose]

That video shows dumping a large amount of molten salt into water, not anything like a tiny drop of water into a relatively large amount of molten salt. Not disputing anything, I'm just asking for a relevant citation. The assertion was that "any moisture" could cause an explosion. That's pretty dire.
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I hereby assert that any moisture will react to molten salt in a manner commensurate with the amount of moisture involved. A drop of sweat or a drip from your beer would be like setting a blackcat off on the surface of the salt.

 

[Brians356]

I hereby assert that any moisture will react to molten salt in a manner commensurate with the amount of moisture involved. A drop of sweat or a drip from your beer would be like setting a blackcat off on the surface of the salt.

Gosh.
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[PDS]

Just Google "molten salt bath safety". Lots of info from industrial sources and an interesting thread from Blade Forums. Makes a propane torch seem pretty tame.

 

[jds holler]

Many of us have been dealing with molten lead on a regular basis, and the danger of water in that situation. It is no different than using care when handling powder and primers.

This method seems to offer an easier and much more regulated alternative to almost all of the popular annealing processes that seem to be in common use.

I've already got a couple of thermostat controlled lead furnaces, high temp thermometer, -- I may finally have to try a little case annealing. jd

 

[Prose]

Sorry, don't get me wrong, I think salt bath annealing is pretty slick, and safe too. I didn't mean to imply that you will explode if you do this, I was only referencing a worst case scenario if a person were to much it up. I hereby attest to the safety of this process!

 

[DRNewcomb]

Please elaborate.
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Similar to working with molten lead. Anything which might contain even a slight amount of water (e.g. jacketed bullet recovered from berm) must be heated up from room temp to drive the water off before melting. One drop of water under the molten lead can cause the contents of the pot to erupt, with disastrous consequences.

 

[SheepDog]

A molten salt bath is hygroscopic. It readily pulls water into the molten salt. Water expands 100 times its volume going from a liquid to a gas. The steam continues to expand with temperatures over 212F. The molten bath is 1000F so you get from water to superheated steam in a few milliseconds. The result is a shower of molten salt pushed out at relatively high velocity. It can be very dangerous. Working outdoors will require a covered area to prevent contaminants from entering the salt bath. You should wear full face shield and protective garments - like welders leather. You might never need it, but if you do need it it will be too late to get it. It's going to leave a mark and it's going to put you in the hospital. With the proper use and protective gear it is safe.
You wear seat belts in a car, you wear life vests in a boat, you wear a gun for protection, all of these in case you need it. Do yourself a favor and wear the proper safety gear.

 

[Gabe22BR]

nothing like sticking your BRASS cases in corrosive liquid...

 

[Brians356]

A molten salt bath is hygroscopic. It readily pulls water into the molten salt. Water expands 100 times its volume going from a liquid to a gas. The steam continues to expand with temperatures over 212F. The molten bath is 1000F so you get from water to superheated steam in a few milliseconds. The result is a shower of molten salt pushed out at relatively high velocity. It can be very dangerous. Working outdoors will require a covered area to prevent contaminants from entering the salt bath. You should wear full face shield and protective garments - like welders leather. You might never need it, but if you do need it it will be too late to get it. It's going to leave a mark and it's going to put you in the hospital. With the proper use and protective gear it is safe.
You wear seat belts in a car, you wear life vests in a boat, you wear a gun for protection, all of these in case you need it. Do yourself a favor and wear the proper safety gear.

Golly.

"Life contains a particle of risk."
Allardyce T Meriweather
"Little Big Man"
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[Brians356]

Safely annealing cases in molten salt:


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[jds holler]

Jeese, I must really live on the edge. The risk of this process seems pretty negligible.

I sure like the idea of dipping my brass in a pool of liquid of a known and sustainable temperature as opposed to a flame of nearly un-regulatable, unknown, and unrepeatable temperature. jd

 

[BoydAllen]

On the corrosion angle, has anyone seen any evidence of this on cases that have been annealed in this manner? For that matter, what data is available regarding the corrosive nature of these liquid salts on brass?

 

[jds holler]

On the corrosion angle, has anyone seen any evidence of this on cases that have been annealed in this manner? For that matter, what data is available regarding the corrosive nature of these liquid salts on brass?

Brass has frequently been used in nautical fixtures and other places where corrosion resistance is needed. I think that with a water bath after treatment, the point would be moot. jd