Home Forums Hunting & Shooting BPCR Brass annealing

Figure this to be the best place for sage advice on the topic, so rather than dance around I'll get to the point.

Amidst all the different approaches used for annealing, I read of one today that was interesting. Found it in a thread about using molten lead to anneal and there was all manner of humor in the thread until one fellow said he used sand rather than lead. Thermometer up around 750*, stuff the case in to the desired depth and withdraw a few seconds later, 6-8 as I recall.

Any of you ever try that?

No problemo,....

I just wander outside around 1400 hours on a balmy June afternoon and dunk em' in the dirt in front of the shop.

Azzing around switch off.

For precision, NOTHING,...and I mean NOTHING beats common Niter Salts.The "degree" of precision that a good controller and a lab grade thermometer / pyrometer allows is WAY ahead of lead , alloys thereof, sand, ....etc. Same same drawing temper on flat springs, and lower temp, CRITICAL heat treating. The technology's 500 years old, if a day.

I've played with induction a bit, and it shows great promise, but the cost of IR gear to really roll that into practicality is way beyond a little farm budget.

GTC

OK then, tell this tale of nitre salts...I am ignorant.

D

Heard of it but not given it a try. Work in my darkened garage with all manner of cartridges spinning necks in a butane torch. At the first hint of a glow they're dropped into a pail of water. The real purpose of the water is simply to expedite handling. If dropped on a hard surface they might take on a dent.

Probably use a tenth of the fuel that one would consume to heat up a lead pot.

I would explain how I do it. But then I would have to listen to all the resident rocket surgeons telling me what I do is wrong.

Same Niter salts one uses for bluing.

Better thermal stability,and recovery to process temperatures because of its lighter viscosity.

No affinity for Zinc,...which most any let pot DOES have.

No headaches if some of the salts do stick to a case,.....and lead can be a PITA , in that particular regard.

GTC

Thanks, will give that a whirl.

Thinking I need a wad cutter too....and some cork.

Salt bathes are neat stuff. The heat transfer rate is much faster than air, and more consistent than in using a torch. We specify salt quenching (austempering) when we want to heat treat spring stampings with minimal distortion.

There may be some useful info here:

http://heatbath.com/2012/06/the-basics-of-molten-salt-quenchants/

The "sand" approach is also called fluidized bed treating - you pump air into a vat of heated sand, so it liquifies, making it easy to insert & remove the parts. The sand is less corrosive than salt, of course, and safety Nazis usually are less excited about it.

The key safety warning is - parts be must 100% free of water, liquids, etc, or you'll get a steam explosion. I heard of a plant in Pennsylvania some year ago, where a worker was annealing some tubing. Unbeknownst to him, there was some water in some of the tubes. A steam explosion resulted, blowing molten salt all over him. He did not survive.

Probably unnecessary to mention to experienced handloaders, but a live primer or powder would have a similar nasty result.

always about half tuckered out here,.....thanks for defining the actual advantages in such brief and concise terms.

gotta' say I'm having a hard time visualizing, "fluidized sand" being screaming nutsoid HOT,....and way beyond the lower temps required for annealing cartridge brass.

I think what the term refers to is that releasing air into the sand column from below will, in essence, float the sand a little and make it easier to "submerge" items in the matrix.

Otherwise making sand into a fluid takes a few more calories that I want to screw with.

Of course I could be fulla chitt.

Yep, the sand itself does not melt - the air bubbling up through it essentially liquefies it.

http://www.getottenassociates.com/pdf_files/Fluidtherm%20-%20Fluidized%20Bed%20Furnaces.pdf

I have enough damned DUST and airborne silicates to deal with on a day to day basis, without adding another source therefor,

Gotta say that a COARSE 'bed' of well screened quartz, or perhaps glass beads would certainly be sompin' to look at,...

Does one heat the AIR, that's doing the fluidizing ?

New area to play in,....eh ?

All said / done, ya' can't cherry out screw heads in sand, the "air" will damned sure induce oxidation,....No ?

GTC

Greg, the only one I have seen in use was at a heat treat shop in California and they weren't talkative about what they ran in it. Google "fluidized bed furnace" and you'll get a variety of hits as far as people making them. AFAIK they bury electric heat elements in the sand, then bubble up just enough air through the bottom to get the sand to liquify.

I would guess that an inert gas would eliminate oxidation. That said it seems a bit more complicated than I have time to fool with.