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View Full Version : Why do some consider torch annealing superior to salt?



Mram10
03-20-2019, 12:27 AM
Salt bath temperatures are much easier to monitor and adjust. I set my pot at 430c (800f) and dip the necks for an 8 count. It is much harder to accurately anneal with map gas at 3000+ deg F. Easy to ruin necks in a milli second of extra heat.
Why havenít more moved to salt bath annealing?

murray brook
03-20-2019, 12:34 AM
By what I've read on different sites I believe there are quite a few loaders that have taken up the salt bath method.

brickeyee
03-27-2019, 03:58 PM
By what I've read on different sites I believe there are quite a few loaders that have taken up the salt bath method.

With a good temperature sensor (like a thermocouple), a PID controller (they are very inexpensive now), and a high power switch (often a single transistor) you can set the temperature you want and it will be maintained.

You can get all the parts for less than $50 if you look around.

It also provides better control over a typical lead pot temperature.
They will heat up as fast as they can and then maintain a set temperature with no real attention being paid.

A PID controller is more sophisticated than a typicality bang-bang (on/off) style thermostat.

Even when the switch only allows on/off control of the heater the PID will turn it on and off multiple times per minute to obtain smoother control (variable duty cycle).

johan teughels
03-28-2019, 01:59 AM
plans ? i use a lee meltingpot but if there are better systems i like to get the info how to build one /what areyou using for salt mixture ?

brickeyee
03-28-2019, 02:43 PM
plans ? i use a lee meltingpot but if there are better systems i like to get the info how to build one /what areyou using for salt mixture ?

IIRC Lee pots have a simple mechanical thermostat.

The heating element is either full on or full off.

This makes the temperature wobble around a set point.
The variation can be larger though.

There are a number if salts that can be used to create a mixture that has a desired melting temp.
Potassium nitrate and sodium nitrate are common.

2 parts potassium to 1 part sodium IIRC.

I still put some Tempilaq on the head as a warning/backup.
Not real high stuff either.
Around 450 F. Low enough that no annealing should occur if you do just hit it.

If that spot melts the case is scrap.

Amazon has some nice 'kits' of a PID controller, a TRIAC to boost output power for the load the pot puts on the system, a heat sink for the TRIAC, a thermocouple in a probe to measure the temperature.
All in a kit around $40. Like this one:
https://www.amazon.com/Inkbird-Thermostat-Temperature-Controller-Thermocouple/dp/B01489AQAW/ref=sr_1_6?crid=2QPSWHBGNN2NT&keywords=pid+controller+kit&qid=1553795537&s=gateway&sprefix=pid+controller+%2Caps%2C151&sr=8-6

A lot of the PID manufacturers have suggested schematics for setup.

For a 120 V load (the pot) parts are pretty common and standardized.

And keep in mind the idea is to partly anneal the brass.
If it goes dead soft in the neck you will have very close to zero neck tension.

An annealing temperature that allows for about a 1 minute dwell at temperature is desirable.

It allows tie for the brass 'crystal' structure to move around without growing excessively large or over annealing.

TrxR
03-28-2019, 02:52 PM
Some are using the lee pot and a pid to control it.

murray brook
03-28-2019, 08:25 PM
With a good temperature sensor (like a thermocouple), a PID controller (they are very inexpensive now), and a high power switch (often a single transistor) you can set the temperature you want and it will be maintained.

You can get all the parts for less than $50 if you look around.

It also provides better control over a typical lead pot temperature.
They will heat up as fast as they can and then maintain a set temperature with no real attention being paid.

A PID controller is more sophisticated than a typicality bang-bang (on/off) style thermostat.

Even when the switch only allows on/off control of the heater the PID will turn it on and off multiple times per minute to obtain smoother control (variable duty cycle).

So far all I've used was the Lee pot to control the temp, and it works good, but I can see where the PID system would be a great up-grade. I'll have to look into this.

johan teughels
03-29-2019, 03:01 AM
the pid you mentioned goes to 400c you use 430c ?
is 430C high enuff ? some info i got heat to 500-550C

Al Nyhus
03-29-2019, 09:18 AM
It is much harder to accurately anneal with map gas at 3000+ deg F. Easy to ruin necks in a milli second of extra heat.

And that's why I don't use MAP gas for annealing......;)

Mram10
03-29-2019, 04:45 PM
I bought one of these to save time. Itís proven already.

https://ballisticrecreations.ca/

The temperature doesnít vary much at all. When doing rum cases, i turn it up 10c+ hotter to account for cooling from cases. Much more temp stable than torches

Mram10
03-29-2019, 04:54 PM
the pid you mentioned goes to 400c you use 430c ?
is 430C high enuff ? some info i got heat to 500-550C

Brass will anneal at 800f(430c) within a few seconds. My necks are usually around .0125Ē depending on case so it happens quickly. You can go as high as 550c with the salts according to the setup he sells, but I prefer to stay closer to the 800f. Iím sure there are better ways though

brickeyee
04-01-2019, 04:10 PM
the pid you mentioned goes to 400c you use 430c ?
is 430C high enuff ? some info i got heat to 500-550C

The thermocouple is rated for 400 C.
It will go further just fine but may not last as long.

The thermocouple junction itslef is good 2,460F.
The wiring and enclosure material around the actual device are what is limiting its range.

Engrbill
04-02-2019, 02:43 PM
I bought one of these to save time. Itís proven already.

https://ballisticrecreations.ca/

The temperature doesnít vary much at all. When doing rum cases, i turn it up 10c+ hotter to account for cooling from cases. Much more temp stable than torches

I have checked his website for a month. Non for sale. Guess he doesn't make the kits anymore. He claims he does, just keep checking, but no luck.

Pete Wass
04-02-2019, 04:35 PM
for his real job so may be afield.

Pete

Mram10
04-03-2019, 12:25 PM
Wouldnít be hard to make a kit.
Lead pot
Salts
Laser thermometer
Double plate for dipping

Donít need temp control. It isnít important. I set mine at 7 on the dial and it keeps it around 430c ish. For bigger cases I start hotter

Mram10
04-03-2019, 12:37 PM
Hereís a basic list

brickeyee
04-03-2019, 01:34 PM
Wouldnít be hard to make a kit.
Lead pot
Salts
Laser thermometer
Double plate for dipping

Donít need temp control. It isnít important. I set mine at 7 on the dial and it keeps it around 430c ish. For bigger cases I start hotter

An on-off (AKA bang-bang control) is not as accurate as the control from a PID.

And you will need to adjust the IR thermometer for the emissivity of the salts.
Other than on a flat black surface they are NOT all that accurate.
Displayed digits is NOT accuracy and resistivity affects the color of the IR spectrum emitted.

The 'progression' of colors for IR operates just like visible and changes with temperature and surface.

A PID controller will turn the heating element off with rapid short pulses based on the rate the temperature is changing and how far it is from the desired set point.

The on off pulses narrow as the temperature approaches the set point.

Mram10
04-03-2019, 03:15 PM
Your setup would be more accurate, but IMO a controller isnít needed beyond what the pot comes with. An ir thermometer only needs to get you in the 420-550c range. That is close enough to anneal the brass. Without a controller it is far more consistent than torch setups.

brickeyee
04-03-2019, 04:41 PM
Your setup would be more accurate, but IMO a controller isnít needed beyond what the pot comes with. An ir thermometer only needs to get you in the 420-550c range. That is close enough to anneal the brass. Without a controller it is far more consistent than torch setups.

And with a controller is even even more accurate.

Keep in mind the idea is NOT to completely anneal the case neck.

It is to soften it without making it dead soft.

At dead soft you will have ZERO neck tension to hold the bullet.

Bob Brushingham
04-11-2019, 10:23 AM
Where can you get it in this country?
Brush

bbrawand
04-11-2019, 02:02 PM
Can you aneal necks this way by raping body of case bill b

bbrawand
04-11-2019, 02:09 PM
Can you aneal case necks by wraping body of case in treating foil in heatreating furance bill brawand thanks

GeneT
04-12-2019, 08:50 AM
Can you aneal case necks by wraping body of case in treating foil in heatreating furance bill brawand thanks

No. Foil will not prevent the body from becoming annealed as well.

GsT

Mram10
04-12-2019, 11:45 PM
Salt annealing is much easier and cheaper to do correctly if you donít need an automated setup for tons of brass. Even 100 doesnít take too long

waynemac1
04-14-2019, 08:07 AM
ĎAt dead soft you will have ZERO neck tension to hold the bullet.Ē

I use an induction heater to anneal brass with and have been trying different shades of red to determine the temp I want the brass. I have taken it to red all the way down into the shoulder and still have plenty of neck tension to hold the bullet. Now to qualify that statement, this is on LC 5.56 brass cases of recent manufacture, and they feed and function in an AR-15.
My PPC and Beggs cases are taken to a slight glow in a low light setting which Iím sure is still well over 800 degrees, and have not seen a reduction in case neck tension.
Now, I donít claim to know the best way to anneal brass, my reasoning to do it this way has to do with repeatability and time. It takes about 14 minutes to do 100 pieces of brass, and thatís at a leisurely pace. Still, I want to learn what others are doing and why. I have found that with annealed brass, my headspace can be adjusted to the .001 with virtually no spring-back, yet Iím reading that dead soft is not the goal. Iím not up to speed with you guys, so please help me along a little.

Wayne

retired
05-17-2019, 08:45 AM
try this link
https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

Mram10
05-17-2019, 10:42 PM
try this link
https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

I read your sacrilege :)

It doesnít make sense that heating brass to 800f doesnít anneal, salt or not. Every metallurgy table for annealing calls for 800f ish. I have had good results in the press and on paper with the salt. Any red while using a torch is too hot. Iíd like to see more info from an unbiased source.

We need a simple equation showing how long it takes to heat the neck area, aka, .015Ē of brass to absorb 800f deg of heat. Iíll try and look it up

brickeyee
05-28-2019, 02:27 PM
At one point I had a very precise chart that showed crystal
structure changes in brass as a function of time and temperature.

It used larger pieces of cartridge brass to allow easier sectioning and
microscopic examination of the polished cross sections.

I cannot locate it, and have not found another.

Annealing is a function of both time and temperature.

If you are doing things by hand (like salt bath dipping) you want a slightly
lower temperature to help extend the required time and reduce variation.

An error of 1 second on a 4 second anneal is a lot worse than a 2 second error on a 10 second anneal.

And hardness measurement are a correlated measurement as opposed to cutting and
polishing a brass section and examining it under a microscope to determine the size of crystals in the metal.