Dark necks on annealed cases

[Cole440]

The two with bullets in them are from my last batch of cases. The three without bullets are from the current batch.

I haven't seen the darker brown/black color before. I recently switched to a hotter torch, but also changed my annealing time to compensate.

Looks like the heat line on the cases is in about the same spot. I'm not at all worried about the integrity of the brass. I just thought I'd see if this is normal/common?

 

[ArTeeKay]

Intuition says it's likely to do with residue of some kind on the cases when you hit them with the torch. Without knowing your cleaning or annealing process, it's hard to pin it down.

 

[PinesAndProjectiles]

It looks like your torch flame was more concentrated on the necks of the three pieces w/o bullets in them, and more at the shoulder junction on the other two.

 

[Haney]

Could the brass have stopped rotating while the torch was on it ?

 

[Dolomite]

Did it turn a red glow?

 

[Cole440]

Did it turn a red glow?

I usually set it up so they just start to have a dull red glow when they come out of the flame.

 

[Dolomite]

If I remember correctly the dark color is from it being in the flame a little too long or the neck had lube on it, but you don’t have that blue heat line on the brass. What kind of gas are you using?

 

[Cole440]

Regular propane out of a 20lb bottle and a swirl flame style torch

I had wet tumbled these cases with pins, lemishine, and some simple green wash and wax before I annealed them. That might have contributed a little. Or maybe I just got the necks a little too hot.

I'm not worried about the bodies being soft though and the necks sized and are holding tension just fine, so either way I'm going to shoot them and see how it goes!

 

[straightshooter1]

Regular propane out of a 20lb bottle and a swirl flame style torch

I had wet tumbled these cases with pins, lemishine, and some simple green wash and wax before I annealed them. That might have contributed a little. Or maybe I just got the necks a little too hot.

I'm not worried about the bodies being soft though and the necks sized and are holding tension just fine, so either way I'm going to shoot them and see how it goes!

Since you're annealing after cleaning, I'd say it's residual cleaning solutions that are being burned.

If you're going to wet tumble, I'd suggest you do that after you've annealed; since the annealing process always leaves a somewhat rough oxidation coating of the outside and inside surfaces of the necks which can interfere with consistent seating. I always anneal before cleaning for this reason.

 

[Im2bent]

The two with bullets in them are from my last batch of cases. The three without bullets are from the current batch.

I haven't seen the darker brown/black color before. I recently switched to a hotter torch, but also changed my annealing time to compensate.

Looks like the heat line on the cases is in about the same spot. I'm not at all worried about the integrity of the brass. I just thought I'd see if this is normal/common?

View attachment 8357963

Not so fast Kimosabe, by that logic I can crank my oven to 550 and cook my turkey in half the time. My point? You have more intense flame at the neck and shorter time for the heat to get the shoulder to temp.

 

[Cole440]

Since you're annealing after cleaning, I'd say it's residual cleaning solutions that are being burned.

If you're going to wet tumble, I'd suggest you do that after you've annealed; since the annealing process always leaves a somewhat rough oxidation coating of the outside and inside surfaces of the necks which can interfere with consistent seating. I always anneal before cleaning for this reason.

Good thoughts! I hadn't really considered that. I could flip flop the cleaning step. I dip my cases in dry lube before mandrel sizing the necks so I'm not super worried about the seating force (that being if they are totally clean that should be ok).

 

[Cole440]

Not so fast Kimosabe, by that logic I can crank my oven to 550 and cook my turkey in half the time. My point? You have more intense flame at the neck and shorter time for the heat to get the shoulder to temp.

Excellent comparison. The reason I didn't really suspect that is that the new flame is much broader and washes over the case a lot more than the pencil flame did. But you still make a good point.

 

[Dolomite]

That black mark is from the wax reside left on the case after cleaning. If you annealed a clean piece of brass with no wax used on brass the heat will turn the necks darker color and have a faint blue line below the shoulder which means you have over annealed the brass some.

Try cleaning the brass with no wax or polish additive and then anneal. The necks turn darker color not pure black and there should be a faint blue line below the shoulder.





Or this video explains more

 

[Haney]

That black mark is from the wax reside left on the case after cleaning. If you annealed a clean piece of brass with no wax used on brass the heat will turn the necks darker color and have a faint blue line below the shoulder which means you have over annealed the brass some.

Try cleaning the brass with no wax or polish additive and then anneal. The necks turn darker color not pure black and there should be a faint blue line below the shoulder.





Or this video explains more

The necks turn darker color not pure black and there should be a faint blue line below the shoulder.

If you annealed a clean piece of brass with no wax used on brass the heat will turn the necks darker color and have a faint blue line below the shoulder which means you have over annealed the brass some.

So, which is it? Does your Faint blue line theory mean over or under annealed ?

 

[Dolomite]

I don’t have any technical data but I anneal and have both the faint blue line and dark necks.

 

[straightshooter1]

I don’t have any technical data but I anneal and have both the faint blue line and dark necks.

Don't worry about the colors as it has nothing to do with annealing of the metal that's taking place. The colors are about the interation of the heat with residues on the brass and the gases in the flame.

Do an experiement of your own by taking a piece of brass and clean it throughly with some steel wool. Then anneal it as you would normally and see what you get.

Here's a single Federal .308 case I picked up at the range the other day, cleaned it with steel wool and subjected it to a little higher heat than I normally use for annealing AND for twice as long: