Annealing Set-ups: immersing cases in solid media?

[Jäger]

Recent discussion here has once again caused me to think about changing from my fingers 'n alcohol lamp method of annealing, which I'm aware doesn't give me optimal annealing results, although it does work to sufficient effect to extend case life.

Two of the immersion methods out there are dipping in molten lead and the alternate is dipping in a molten salt bath. One turn key solution for salt bath immersion was mentioned here a few days ago and has been bouncing around assorted forums for a few years now.

That leads me to a recurring thought of thinking of trying immersion in a solid substance instead. Sand I have seen mentioned a few times in the past, but I haven't seen a writeup accompanying that. Now that I have a PID/PLC arriving shortly to control my Lyman pot, I am turning my thoughts to trialing immersion annealing in a solid media, using the PID to hopefully control the temperature of the solid media.

Sand is readily available, but what about alternatives that might give better conduction of heat from the media to the case?

Alternatives that have come to mind this morning include very small glass beads (like the ones the optometrist used back in the 60's to heat the earpieces of your birth control eyeglasses in order to twist and bend those to shape the frame to fit your head); I have seen 1mm glass beads offered for sale online for crafts. Or rather than glass beads, the sandblasting media advertised as 40-50 grit should be much smaller - but perhaps tend to be too fluffy? Or perhaps some much more dense solid: during my brief mining career long ago, we used magnetite in some processes. I remember how incredibly dense (and heavy) it was when you shoveled it.

Any engineers/SMEs out there with opinions and suggestions on what might be the most optimal granular/powdered media to use for immersion annealing?

I'm presuming the greatest drawback will be coming close to the heat transference properties of liquids like molten lead and salt. The upsides (at least I think) would be fewer hazards involved, ease of handling and storage when done, etc. I'm assuming the right media would allow you to simply stick a plate with shell sized holes in it on top of your media, poke the cases you're annealing into the media below those holes, and then remove after the proper amount of time.

Thoughts, suggestions, etc?

 

[RicinYakima]

Holes in a heated aluminum plate.

 

[Schweisser]

I worked with molten salt baths professionally for years and I dislike them from a mess and safety standpoint.

I've never tried it, but one idea on my list to try is using steel shot blasting media -- which is available in very small sizes -- instead of salt. I have a bag of shot that's about 0.007" diameter that I bought from my former employer for a few bucks. I'm not sure what steel shot media costs in small quantities.

 

[Jäger]

I'm not ignoring concerns about molten salt baths - but I am also using a process that involves a pot full of molten lead just a few feet from my face. And I am the guy who wears a wide brimmed hat and face shield along with leather apron, long sleeves, and work boots when casting. So I appreciate caution with molten salts, whatever kind they are. Which is why I'm curious about using other media as the source of heat.

A fine sized steel shot sounds like a good option.

I wonder whether the fine steel shot would transfer heat to a case better than fine glass beads?

Glass Bead 80 Grit Abrasive Media

 

[Joshua]

Fire Good!

Expensive Bubbling Caldron Bad!

Here is how I do it. It’s cheap. It’s repeatable. I posted this back in October.

“This is the part of the conversation where I explain how I anneal by hand. Then someone comes back and tells me that there is no possible way that I have any consistency with my method. Then I snap back with the “I’ve been running torches for thirty years” rant.

Oh wait a minute! I’m not on “that” Forum right now.

I use a metronome app on my phone to time every annealing cycle.

The variable speed drill motor is bolted to a pivot point, via the side handle clamp. The motor speed is set with a piece of tape over the trigger. A deep well socket protects the lower portion of the brass. The propane torch is set to it’s lowest setting.

Swing up past the flame and load the socket. Swing to the flame. Count off to the metronome. Swing past the flame and brass drops into the water bucket on the floor.

How do I know how hot, how long? That’s where a temperature indicating crayon and thirty years of brazing and welding comes into play.

I am comfortable with the results that I get.”

 

[BBerguson]

I’ve watched the videos and read the posts about the dipping method. My lead pot is bottom pour so I’d have to do it one at a time, which isn’t a big deal because that’s how my fire method will work too. I’d use lead if I were going to do it because I’m not going to put salt in my lead pot and I see zero advantage to using salt anyways when I already have molten lead.

Anyways, my first attempt is going to be similar in function to the nice commercial units. I’m going to use two torches because my motor is only 3rpm and I’m going to make the case feeder disk a manual operation. I don’t want to heat them for 20 seconds (1 full turn) so I’m thinking with two torches, I should be able to do as little as five seconds (1 quarter turn) and get the heat evenly around the entire case. That and I don’t want to wait 20 seconds per case! This is my plan anyways...

I like the homemade annealers that use a pot with slots cut into the side. If I had an old pot, which I don’t, I try that knowing that with my 3rpm motors, I think I’d need 2 or 3 slots cut so I didn’t over heat the brass. I have some coffee cans but I’m afraid they’d be too weak after I cut the slots. Maybe I’m wrong, one case doesn’t weigh that much so maybe I’m over thinking it. I guess I’ll have to cut one and try. I have 3 motors so I can make both types If I want to.

Just making some crude drawings and plans right now because I still don’t dare to take chances with my neck yet. Dr. Appt on Feb 4th with x-rays so I have to wait until after that to really do anything...

 

[Ian]

They key to efficient heat transfer using a granular dipping media is very fine media size and a high thermal coefficient. Copper powder comes to mind. Aluminum or brass powder might also work well, though oxidation will definitely be a factor. Perhaps a reference of the thermal coefficient of the oxides would be in order.

HOWEVER, I actually started looking into this and it appears there may be some issues. Regarding the molten salt bath, https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

Any granular media will have a recovery time for the area just used, so there is no guarantee of consistent temperature even if a pattern of dipping is followed in an effort to keep the temperature of the media equalized.

 

[Rally]

Could common auto anti-freeze be heated safely, maybe a mixture of sand and anti-freeze?

 

[S Mac]

I would say the boiling point of antifreeze would be well below the temp needed to anneal brass.

 

[Joshua]

Ok, how about Mercury! If it boils you know your too hot!!!

 

[blackthorn]

I am really sorry for the thread drift, BUT---The OP said---"Alternatives that have come to mind this morning include very small glass beads (like the ones the optometrist used back in the 60's to heat the earpieces of your birth control eyeglasses in order to twist and bend those to shape the frame to fit your head);"

Can someone please explain just how that would work?? Maybe keep you from sleeping with ugly people?? Inquiring (and twisted) minds want to know!

 

[BBerguson]

They key to efficient heat transfer using a granular dipping media is very fine media size and a high thermal coefficient. Copper powder comes to mind. Aluminum or brass powder might also work well, though oxidation will definitely be a factor. Perhaps a reference of the thermal coefficient of the oxides would be in order.

HOWEVER, I actually started looking into this and it appears there may be some issues. Regarding the molten salt bath, https://www.ampannealing.com/articles/52/salt-bath-annealing--does-it-work-/

Any granular media will have a recovery time for the area just used, so there is no guarantee of consistent temperature even if a pattern of dipping is followed in an effort to keep the temperature of the media equalized.

That was a very informative article, thanks for posting it Ian. Certainly ”quenched“ any desires I had about annealing cases by dipping them in something. Sounds like fire is the king of annealing.

 

[Ian]

I've used lead alloy for a light draw and tested the effectiveness using calibrated Vise Grip pliers to gently squeeze the neck a slight amount so that springback could be checked. Not a Vickers test but it did work for my purposes at the time.

Heat does weird things sometimes, or should I say heat transfer does strange things to materials sometimes, not always what you would think, either.

Take for instance a bullet quenching test I did concurrently but independently from another member here. We were attempting to harden the bases of low-antimony bullets by water-quenching instead of torch-annealing the noses for "softnose" bullets. Well, guess what? It worked IN REVERSE. The tips of the noses were the HARDEST after aging, and the bases the most soft (air-cooled hardness)! I think it might work if the bullet is reasonably long and thin and the NOSE was briefly quenched from the anneal temperature (pulled from the oven with needlenose pliers after a long, hot soak and immediately quenched). We discussed this at length and all we can figure is that when quenching the bases the heat got sucked out of the noses so fast that they hardened, but the heat feeding the base from the rest of the bullet slowed down the quench rate sufficiently to bypass the hardening window.

 

[358156 hp]

I'm still plugging away with the old "Tempilaq inside the case mouth, spin the case in the flame of a propane torch in a deep socket" trick. I thought the steel shot idea had merit, but I also see potential drawbacks. Maybe I'll just pick out a plan I like and make my own annealer.

I love gadgets!

 

[Ian]

I sure like Joshua's method. Will probably set something up similar. I'd buy an Annealeeze but it doesn't look like it would do rimmed cartridges, though a slight design change to the feed chute would correct that.

 

[S Mac]

I'm still plugging away with the old "Tempilaq inside the case mouth, spin the case in the flame of a propane torch in a deep socket" trick. I thought the steel shot idea had merit, but I also see potential drawbacks. Maybe I'll just pick out a plan I like and make my own annealer.

I love gadgets!

I have never used Tempilaq, just ordered some. You place inside the case mouth? Guess I assumed below the shoulder on the exterior would be proper placement.

 

[L Ross]

Jäger, Sir, what you and I have been doing works, just flat out works. Why mess with it? I know you use an alcohol burner and I use a Bernz-O-Matic , but our fingers really are pretty delicate, plus I count in my head and I observe the brass as I'm annealing.

I'll save my over thinking for more serious topics, such as why do fish get the doldrums in Mid-Winter?

 

[358156 hp]

I have never used Tempilaq, just ordered some. You place inside the case mouth? Guess I assumed below the shoulder on the exterior would be proper placement.

I use 750* degree Tempilaq inside the case mouths. My concern with using the Tempilaq on the exterior of the cases is that it may not get a consistent anneal since the Tempilaq is being heated directly on the exterior surface.

 

[Ian]

Funny, I literally just ordered one last night:

 

[358156 hp]

A tire inflater and an o-ring kit for Valentines Day? I had no idea you were such a romantic