Annealing brass with a Kiln

[Faret]

I know some of you anneal your brass with a Kiln. Would like this to be a thread on techniques, temp, time and how you set up the Kiln for such a operation. For those that heat treat their homemade dies with one feel free to jump in as well.

TIA

[Nueces]

From my reading of your post, I believe there to be a misunderstanding. Using a kiln or other furnace arrangement to anneal brass cases would leave the entire case soft, to include the head. This sort of treatment utterly destroys the case for further use, as the strength of the head has been reduced too much. While brass may be annealed, and thereby softened, by using heat, it may be hardened only by 'working' it, i.e., by rolling, forging, case-sizing, etc.

Case annealing, usually called case neck annealing, involves heating the neck and/or shoulder area quickly, so as not to overheat the head. Often, a dunk in water is used to eliminate the possibility of too much heat traveling down to the head, but the cooling has no effect on the resulting hardness.

Or, did I misunderstand you.

[BK7saum]

Nueces, he's referring to annealing cases for swaging bullets. They need a full anneal to be able to work them in the swage dies.

[ReloaderFred]

I use a kiln for annealing large batches of brass. My technique is to stack the cases tightly in a stainless steel tray (actually, 2 of them), with the cores already inside the cases. I heat the kiln to 1,125 degrees F, and when it reaches that temperature, I turn the kiln off and let it set overnight. This bonds the cores to the brass without the use of flux, which is hard on swaging dies.

Tray of cases and cores ready to put in the kiln:



Here's another view:



And here's a batch after sitting all night in the kiln. They were still 240 degrees F. after the kiln had been turned off for 12 hours:



Hope this helps.

Fred

[Faret]

From my reading of your post, I believe there to be a misunderstanding. Using a kiln or other furnace arrangement to anneal brass cases would leave the entire case soft, to include the head. This sort of treatment utterly destroys the case for further use, as the strength of the head has been reduced too much. While brass may be annealed, and thereby softened, by using heat, it may be hardened only by 'working' it, i.e., by rolling, forging, case-sizing, etc.

Case annealing, usually called case neck annealing, involves heating the neck and/or shoulder area quickly, so as not to overheat the head. Often, a dunk in water is used to eliminate the possibility of too much heat traveling down to the head, but the cooling has no effect on the resulting hardness.

Or, did I misunderstand you.

Yes for using cases as jackets for swaging bullets.

[Nueces]

Roger, sorry! Can see that from the forum this is in.

I just surf recent posts, must pay better attention.

[Idz]

Question for Fred: Why 1125F temp? Brass anneals at about 600 and lead melts about 620 so why heat so hot?

[Dryball]

With that temp and duration...do you need to clean your cores or does the lube cook off allowing the lead to bond with the jacket?

[ReloaderFred]

Idz,

I picked 1,125 degrees F. simply because that's the temperature Starline uses to anneal their brass. I figured they know more about brass than I do, so I just tapped into their knowledge on the subject. It's in one of the videos on their website about making brass.

Dryball,

The bullets I used for cores have no lube. I cast them of almost pure lead, with a Bhn of 6, specifically for using as cores. It was by accident that I learned that leaving them soaking overnight bonded the cores to the brass without the use of any flux. I found that letting them cool to about 200+ degrees F. made them easier to handle than with molten cores. My old ceramics kiln is so well insulated, it takes forever for stuff to cool down when the lid is left closed, so I just left them overnight out of not wanting to handle them while molten.

I lift the trays out of the mold in the morning and just set them on the concrete floor to cool off the rest of the way. The tray pictured above had cooled completely before I set it on my bench.

The .429" diameter 230 gr. bullets I swage are completely bonded. The only way to get the lead separated from the jacket after they're smashed in the impact berm is to melt it off. I've found it to be the same with my .357", .400", .410" and .452" diameter bullets. I use no flux at all, and there's no lube on the bullets when they're put in the cases prior to annealing. Flux is an acid, and if you don't completely clean your swaging dies after using it, an expensive swage die can be ruined if left over a period of time.

Hope this helps.

Fred

[ReloaderFred]

Here is a photo of the steps I take in swaging those .429" bullets from .40 S&W brass. I'm using military .40 brass, made by Federal, since I've found the weights to be so consistent in them. They seldom vary more than a grain or two in weight, which is great quality control. I also have an unlimited supply of them from the Coast Guard using our range for qualifications.



Here is a top view of the same steps:



Hope this helps.

Fred

[ReloaderFred]

And here's the setup I used for swaging those bullets. I've since purchased a used Corbin CSP-1 press for bullet swaging.



And yet another picture:



Note the size difference between my Rockchucker press and my Hollywood Senior. I also have a smaller Hollywood Senior, but I don't swage on it, since it doesn't have the swage bar on the front.

Hope this helps.

Fred

[runfiverun]

and I just realized why my C&H canellure tool is such a pain to use.
you only need to get brass to 715 to make it go dead soft.

[dragon813gt]

Chuckbuster's ultimate cannelure tool is worth the price of admission. It was a joyous day the first time I used it. I may never use the CH tool again but I'm hesitant to sell it. It's backup for now.

[runfiverun]

his tool is super nice but I have the C&H and 2 others, I don't know what I would do with a 4th one.

[dragon813gt]

Use that one all the time while the others collect dust

[Bills Shed]

I was useing a small kiln to anneal my .172 jackets. First I derimmed the .22LR cases then drew them down to .169" and trimed to length, then anneal at 450deg C for 15 min. After I annealed I tumbled to clean the jackets and remove any burrs. I only annealed at 450 for the 15 min for .17 jackets that finish up at .526" long when point formed. I am currently also trialing not annealing at all as they are pointing forming up well with out it. A jacket that long needs to be pretty strong to withstanding point forming when there is only 10.7 gn of lead in the base. It makes an awesome 17 gn projectile that has just shot a .118" four round group. Unfortunately the fifth round blew it out to .684"
I believe I have no "fold ups" during the PF because I trim off over .400" and so remove any cracks and flaws at the case mouth. Find what works for you and go for it. Do not be scared to challenge current thinking and keep experimenting.
Bill

[Faret]

How is everybody setting the temp or are you running a PID controller?

[runfiverun]

I don't really use a kiln.
I use my cast iron pot and a thermometer.
as soon as it hits 750 I turn the heat off and let everything cool down, I have been thinking about going real fancy and using some sand to fill in the air gaps with.

when I melt cores to do jacket bonding I just set them in the bottom of the pot and watch the lead melt.

[Faret]

Well got my brass in the new kiln. Hooked it up to a pid controller that I built. Going for 1000F well see how it works!