Proper temperature for salt water annealing....

[done111]

So question has come up on proper temperature for salt bath annealing. Consensus seems to be 500-550C which is around the 1000F mark and a duration from around 4-7 seconds. Seeing some info for other annealing methods that are shooting for 750F. That’s like a 250F difference! Does anyone have information on why salt bath method is using that temp? Does doing so over anneal the brass?

Don

 

[luckeeshot]

very interesting , my search took me to a video on youtube

 

[JRS]

I'll stick with razor blade juggling, or Cape Buffalo riding. They seem to be much safer.

 

[jds holler]

Thanks for the original post, and the post with vid. I haven't yet annealed a single case in my life, but when I do, this will be the method. I've got a Lee bottom drop pot sitting here doing nothing since I upgraded to a mobetta Lyman pot for casting. I figure I can plug the bottom spout, and remove the hardware to use as the one in the vid.

Seems like this would also be a great way to temper spring steel and such. jd

 

[normmatzen]

JRS,

I'm with you!

I'm not ready to get rid of my Annie! She can anneal on my office desk!

 

[jds holler]

JRS,

I'm with you!

I'm not ready to get rid of my Annie! She can anneal on my office desk!

Well, I'll be able to set the salt bath up on the kitchen table - as soon as I get the lawn mower re-assembled. jd

 

[TAJ45]

Well, I'll be able to set the salt bath up on the kitchen table - as soon as I get the lawn mower re-assembled. jd

Heh heh, I like it! I had my Husquvarna 350 on a 4x8' plywood (pre OSB days) in the living room one winter....

 

[smokinghole]

I think 500c-550c is the sweet spot. You get a nice quick anneal on the neck/shoulder before it have the chance to soak too far into the body. If you go for a lower temp you risk an ineffective anneal or too much soak into the body/head. I did my salt bath bare handed and the case heads were all cool to the touch when I hovered near 510c.

 

[Webster]

So question has come up on proper temperature for salt bath annealing. Consensus seems to be 500-550C which is around the 1000F mark and a duration from around 4-7 seconds. Seeing some info for other annealing methods that are shooting for 750F. That’s like a 250F difference! Does anyone have information on why salt bath method is using that temp? Does doing so over anneal the brass?

Don

1000F should be OK. The reason annealing by flame or induction heating is limited by many to about 750F is because the flame from a torch may be around 2000F an induction annealer can easily melt a case neck. In other words the temp of the case is always increasing in temp. The source of heat with a salt bath is constant. You cannot over shoot. You have to understand that there are different degrees of annealing. Make sure you don't make the necks to soft. You can sqeeze the neck with pliers and tell if the neck is approaching dead soft. After annealing the neck should still have good resistance to crushing. You might want to try 900F and see if there is a difference on the target?

 

[tuttlefarm]

1000F should be OK. The reason annealing by flame or induction heating is limited by many to about 750F is because the flame from a torch may be around 2000F an induction annealer can easily melt a case neck. In other words the temp of the case is always increasing in temp. The source of heat with a salt bath is constant. You cannot over shoot. You have to understand that there are different degrees of annealing. Make sure you don't make the necks to soft. You can sqeeze the neck with pliers and tell if the neck is approaching dead soft. After annealing the neck should still have good resistance to crushing. You might want to try 900F and see if there is a difference on the target?

WRONG............. Zinc melts at 787.2 degrees............. Yellow brass is composed of about 60% or 70% copper; 30%-40% zinc, and trace amounts of tin and lead....... you will end up throwing away all your casing at that temperature.

 

[Metal God]

How do you know what temperature the neck actually reached ? You can't use tempilaq do to it being it direct contact with the salt bath .

The annealing testing I've done ( torch and socket ) seemed to indicate it's almost impossible to get the heat to transfer down to the head at any dangerous temp . My test showed by the time my 450* temp indicator melted at the head the neck and shoulders were glowing red for a few seconds meaning the cases were ruined anyways .

Has anyone tried the salt bath at 750* with tempilaq half way down the case body to see if the heat transfers down that far ?

This salt bath thing is new to me . Has anyone explained how the salt bat only takes 4to7 sec at just under 1k* and the torch method at 2k* takes the same amount of time ? I assume it the fact the entire annealed surface is submerged ?

 

[JRS]

How do you keep water in there at those temperatures? Hot salt at those temperatures would probably leave some nasty scars on your face

 

[mikecr]

I do lead dip process annealing at 800-850deg and this has always turned out great.
But I'm sure it could be done at a bit lower or higher temps than this.
Salt should be similar.

I dip longer at ~20sec for a smooth insertion/retraction that prevents cooling of the lead at surfaces.
With this temperature and immersive contact, I don't think there is too much or too little dwell time for good results.

 

[done111]

How do you keep water in there at those temperatures? Hot salt at those temperatures would probably leave some nasty scars on your face

I messed up on title of thread. Meant to say salt bath not salt water, LOL

 

[done111]

1000F should be OK. The reason annealing by flame or induction heating is limited by many to about 750F is because the flame from a torch may be around 2000F an induction annealer can easily melt a case neck. In other words the temp of the case is always increasing in temp. The source of heat with a salt bath is constant. You cannot over shoot. You have to understand that there are different degrees of annealing. Make sure you don't make the necks to soft. You can sqeeze the neck with pliers and tell if the neck is approaching dead soft. After annealing the neck should still have good resistance to crushing. You might want to try 900F and see if there is a difference on the target?

I would love to have a very exact way of measuring over-annealing of brass. I guess I could leave a piece of brass in for say...3x the time.....and see how that one squeezes with a pliers vs one that I think is done properly vs one that hasn't been annealed to try to get a feel for the property. My luck i wouldn't be able to tell the difference between all three pieces in a blind-fold test, LOL.

 

[Webster]

WRONG............. Zinc melts at 787.2 degrees............. Yellow brass is composed of about 60% or 70% copper; 30%-40% zinc, and trace amounts of tin and lead....... you will end up throwing away all your casing at that temperature.

Cartridge brass melts at about 1700F.

 

[chop house]

takes 4to7 sec at just under 1k* and the torch method at 2k* takes the same amount of time

in my experience 3 seconds is about right on the torch method... 5 is definitely too much in my setup.

 

[smokinghole]

I don't have any templiaq but I can toss in a W/W .270 win or Fed 6.5 Creedmoor case into my salt batch and see how long it takes to get a high temp reading half way down the body and then into the casehead.

 

[Pawnee Bill]

Way too complicated for me, I'll stick to my AMP.

 

[smokinghole]

Way too complicated for me, I'll stick to my AMP.

Not all of us can justify $1200 for a case annealing setup.......nice humble brag though. The salt bath is not complicated at all however, very simple and costs about $60 all up.