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Molten Salt Annealing Rig


Popsbengo

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59 minutes ago, Bob57 said:

Nice job fizz๐Ÿ‘, I like the look of that,and sounds a better way of annealing than with a gas flame, you ought to put it into production as a complete kit, I'd be interested in buying one๐Ÿ˜ƒ

Thanks Bob ๐Ÿ‘

That might be a project in a couple of months time if I can find someone local to laser cut and drill the discs and the bottom plate for a reasonable price....but donโ€™t hold your breath. ๐Ÿคฃ

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Cheers

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fizz

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This is my rig which I had laser cut. It's specifically made for the Lyman melting pot.ย  The top disk is 3mm stainless to provide weight as it sits on the pot. and the lower two are 1.5mm stainless and is held together with a stainless bolt, nuts and washers.

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ย I think I might buy a shorter thermocouple or I might have a hole cut in the lower disk for the thermocouple to protrude through.ย but otherwise I am happy.ย 

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21 hours ago, fizzbangwhallop said:

Thanks Bob ๐Ÿ‘

That might be a project in a couple of months time if I can find someone local to laser cut and drill the discs and the bottom plate for a reasonable price....but donโ€™t hold your breath. ๐Ÿคฃ

ย 

Cheers

ย 

fizz

Ok, thanks fizz, if you get there please let me know.

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I have just stumbled over this thread and find I'm on a parallel path.ย  Also using the small Lee melter and my shell holder is very similar to those here.ย  As the main reason for going the salt bath route was to improve accuracy and consistency of the reloading process over the gas torch method.ย  I was unhappy at the very much 'hit & miss' (a bit like my shooting!) performance of the Lee temperature control. This inaccuracy negates the rest of the concept.

To overcome this I am almost completed the building of a PID temperature controler which is capable of maintaining the salt bath at better than plus or minus one degree C.

As a guide for anyone interested, a PID controller is a load switching device to which a Type K thermocouple is connected.ย  The output controls a solid state relay which connects the load to the Lee.ย  Once a required salt bath temperature is set the PID begins the heating process during which it 'learns' to reduce over and undershot temperatures (which Lee type thermostats do badly) until it is able to maintain temprature at very fine limits.

This type of accurate control is used by brewers.

The total diy cost, including a Lee melter is about ยฃ140

I am looking forward to the trial run.

ย 

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Many thanks chaps for all the input to this thread.ย  I 'need' to start annealing soon as my lad's Lapua Creedmoor cases are on their 3rd/4th firing and a ยฃ1 a case, that's something I want to keep going as long as possible.

Looks like this is something that would suit me better than any of the flame systems....

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I had my disk laser cut which for a one off was quite expensive. I was offered a deal on 10 and did post on another forum to see if anyone wanted to split the deal but got no takers. I think if I did it again I would have the thermocouple hole slightly smaller and I think I would have quite a few drain holes cut in the lower disk say 4mm.

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8 hours ago, Pinkfoot said:

To overcome this I am almost completed the building of a PID temperature controler which is capable of maintaining the salt bath at better than plus or minus one degree C.

As a guide for anyone interested, a PID controller is a load switching device to which a Type K thermocouple is connected.ย  The output controls a solid state relay which connects the load to the Lee.ย  Once a required salt bath temperature is set the PID begins the heating process during which it 'learns' to reduce over and undershot temperatures (which Lee type thermostats do badly) until it is able to maintain temprature at very fine limits.

I'm thinking of making a PID controller but,ย as an ex-process and automation engineer, ย I'mย concerned about running the Lyman heating element at 100% all the way up to temperature, I don't think the standard heater assemble is fit for that, it's designed around a simple ON-OFF thermostat. ย I'm likely to operate an ON-OFF cycle up to a near top temperature target before switching to full PID control. ย I think it safer to be slow and steady with su๏ปฟper-hot oxidising salts๐Ÿ˜๏ปฟ๏ปฟ ย Possibly utilize the standard Lyman 'stat and then bypass with a PID controller.

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28 minutes ago, Popsbengo said:

I'm thinking of making a PID controller but,ย as an ex-process and automation engineer, ย I'mย concerned about running the Lyman heating element at 100% all the way up to temperature, I don't think the standard heater assemble is fit for that, it's designed around a simple ON-OFF thermostat. ย I'm likely to operate an ON-OFF cycle up to a near top temperature target before switching to full PID control. ย I think it safer to be slow and steady with su๏ปฟper-hot oxidising salts๐Ÿ˜๏ปฟ๏ปฟ ย Possibly utilize the standard Lyman 'stat and then bypass with a PID controller.

8 hours ago, Malinois said:

Iโ€™ve also been watching the PID vids on YouTube. A project for next month.ย 

ย 

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Hi there Pops......

I have left the melter as is, other than replacing the mains plugtop with a variant to fit a variant outlet on the control box.

The intention is to find the setting on the melter thermostat which gives circa 600 deg. C. and leave it there.

When the PID is turned on power is supplied to the melter just as if there was no PID control.

Once the salts reach the temperature set on the PID (around 500 to 550 depending on experiment) it will begin to control the temperature.

I feel that if you have concerns as expressed at the rate of bringing the salts up to temperature it would be a simple matter to begin with the melter thermostat low and gradually bring it up until the PID indicated the working temperature and then take the melter stat a smidgeon higher.

Does this make sense?

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1 hour ago, Pinkfoot said:

Hi there Pops......

I have left the melter as is, other than replacing the mains plugtop with a variant to fit a variant outlet on the control box.

The intention is to find the setting on the melter thermostat which gives circa 600 deg. C. and leave it there.

When the PID is turned on power is supplied to the melter just as if there was no PID control.

Once the salts reach the temperature set on the PID (around 500 to 550 depending on experiment) it will begin to control the temperature.

I feel that if you have concerns as expressed at the rate of bringing the salts up to temperature it would be a simple matter to begin with the melter thermostat low and gradually bring it up until the PID indicated the working temperature and then take the melter stat a smidgeon higher.

Does this make sense?

Yes, that's pretty much what I will do. ย Alternatively I may design an electronic controller to do the whole thing and junk the internal 'stat. ย I will probably install an ultimate thermal cut-out too.

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38 minutes ago, Bob57 said:

Just read on another forum, you can also anneal with molten lead, Anyone tried that yet??

Yes, it's a technique that's been around for a long time. ย It relies on the brass not 'wetting out' and the lead sticking (like soldering when flux is applied).

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  • 2 weeks later...

Finished my PID controlled, salt bath annealer yesterday and fidled around to get settings.

Today set to work and with the temp. At 500 deg. Cย  tempered 40 No. 6BR for 4 seconds and 0 No. .308W for 5 seconds.ย  It all worked a treat and sample seating using the Wilson hand dies felt good wรญth 0.001 tension.

This is way ahead of the propane torch method!

The only mรฌnor problem was to remove the hardened salt for storage in an airtight container to prevent moisture absorbtion but this was soon solved by turning the heater back onย to melt enough salt around the lee crucible to let me dump it out into metal container.

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1 hour ago, Pinkfoot said:

Finished my PID controlled, salt bath annealer yesterday and fidled around to get settings.

Today set to work and with the temp. At 500 deg. Cย  tempered 40 No. 6BR for 4 seconds and 0 No. .308W for 5 seconds.ย  It all worked a treat and sample seating using the Wilson hand dies felt good wรญth 0.001 tension.

This is way ahead of the propane torch method!

The only mรฌnor problem was to remove the hardened salt for storage in an airtight container to prevent moisture absorbtion but this was soon solved by turning the heater back onย to melt enough salt around the lee crucible to let me dump it out into metal container.

Nice job. ย I take the jig out of the salts whist molten, let everything go cold and then pop the crucible out of the heating element, turn upside down and knock the 'puck' out to store in a plastic bag. ย I wash the residual salts off and dry everything ready for the next go.ย 

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55 minutes ago, Pinkfoot said:

Am I correct in thinking you leave the crucible fixing screws out in order to do this.ย  I had thought about polishing the inside of the crucible to facilitate extraction.

Yes, on my Lyman pot. ย There are three self tappers, I just discarded them. ย The crucible coating has all but fallen off now and the 'puck' just comes away with a tap.

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