Annealing temps

[dyst0pia]

Yes, I know I will probably get 5 different opinions from 4 different people. Anyways...

Having never read Tempilaq before, I can't quite tell if I'm getting it right. What I've read is to get the neck/shoulder to 750F, but no higher than 800F, so that's what I'm trying to do (but feel free to throw other numbers at me, if that's not what I should be doing). Here are the cases with 750 and 800 Tempilaq applied (750 on the left):


After heating (5 different timings):


Looks like the middle one is what I should use? Am I reading that right?

Side note: it's an induction annealer, so there's no flame to provide a "false indicator" melting on the outside. Tempilaq inside the neck matched the behavior on the outside.

[bubbala]

It's a reaction you're looking for. As soon as the paint changes that's it. Simple as that.

[supergimp]

This^^^

I use this technique and have never had an issue. I do some relatively extreme resizing both up and down (308 -> 358 Win and 45-70 -> 33 Win) and get reliable results.

[dyst0pia]

Thanks for the replies. I guess what I'm asking is confirmation on "reading" the Tempilaq. It looks like there is some change on the right side of the third case (i.e., the 800F), so I guess it is reacting; maybe I'll try in between the second and third timings.

I had considered using a torch and a pan, but (1) I wanted something a bit more precise and repeatable, at least for my own peace of mind, and (2) after having heard of induction annealing, I couldn't just _not_ build a platform myself

[bubbala]

If it's a homemade device, the next thing you need is a turntable.

[Metal God]

First things first , you are correct on the temp . 750* at the neck and shoulder is what you're looking for . How ever you must apply the temp indicator inside the neck . If you put the tempilaq directly into the flame it will melt/change MUCH faster then the brass heats up giving you a false indication as to how hot the brass actually got . By placing it inside the neck you keep the tempilaq out of the flame and when it melts you know the brass reached the correct temp .

Here's what that should look like . These are 308 cases with 750* inside the necks and 450* just below the shoulder .



I could go into great detail as to my test results but It's quite a bit of info and I just don't have the time . I'll try to show the talking points though .

I'll start by saying your best bet is to just buy an annealing machine . They are by far the most consistent . Then there's the question , why are you annealing ? Is it to extend case life or to control the bullet hold/neck tension on each cartridge resulting is consistent bullet release ?

If the latter then the machines are the way to go . If just looking to extend case life then there's really a few ways that will work just fine . Since you are already using a temp indicator ( my recommendation ) let's stick with that method .

As you can see in the pic above I use two different indicators in two different areas of the case . There are a few reasons for this . First it was to test My method of heating the cases using one propne torch and turning the case in a socket with a drill and if I could use 450* below the shoulder and would that accurately show that The neck and shoulder reached 750* .

This pic shows just that . The picture was taken when I saw that the 750* indicator melted inside the neck . I was not looking at the tempilaq below the shoulder . The picture shows the 450* temp indicator melted at the same time as the 750* inside the neck .


Now to take all that one step farther . You need to understand the flame/heat in the pic above was set specifically to get them to melt at the same time through trial and error . The main reason I want to use the Temp indicator outside just below the shoulder is that I found it very hard to remove the 750* from inside the necks after I was done .

So here are a few more pictures showing different flame temperatures giving the same result just in different ways .

PROPANE TORCH


MAPP GAS TORCH


FWIW I found MAAP gas to be to hot and aggressive for annealing . For me it just heated the cases to fast and it was hard to see/get a consistent read on the temp indicator .

I could go on & on but that's all I'm up for now . If you have any questions feel free to ask .

Here are a few links and quotes for you to consider

http://www.annealingmachines.com/how-to-anneal.html Changes start to occur in brass grain structure at 480 degrees Fahrenheit. To properly anneal brass, the temperature needs to be at 650 degrees F. for several minutes--BUT this will transfer too-much heat to the lower case in that time. So we need more heat for a shorter time. We need to raise the neck temp to about 750 degrees F. only for a few seconds to anneal.

Proper annealing seems so ticklish, some handloading experts flatly advise against it. But they’re usually not wildcatters, so they get along with factory brass and see annealing only as a means of restoring resiliency to the necks of tired cases. Also, too much of what has long been printed about annealing has sired a family of false ideas that have led handloaders to ruin a lot of good brass by too much or too little annealing. Buying new ready-formed brass isn’t always a practical option, even for some well-known factory cartridges. It’s almost never an option for the fellow who loads wildcat or obsolete cartridges.

So, despite some otherwise worthy advice, the need for annealing can be inevitable if the brass is to be fit for handloading. Overannealing is a double danger. Only the neck, shoulder, and upper body can be safely annealed at all. The rest of the case must retain its original hardness. The head in particular has to be hard, which is why the manufacture of good brass requires enough draws to work-harden the head. The head (especially) can’t be safely softened, so the annealing absolutely must be confined to the other end, a process that’s ticklish enough with a case as long as the .30-06 and immeasurably trickier with most handgun cases and very short rifle cases. Any annealing of the head is too much.

But the neck is easy to overanneal, too. Get it too hot, which makes it too soft, and it’s too weak to grip the bullet as tightly as it should

http://bisonballistics.com/articles/...rass-annealing How do you tell how hot the brass is? Use a temperature indicator like Tempilaq. Tempilaq is a special sort of "paint" that is designed to melt at a very specific temperature. Get some and use it. Use some 450 degree Tempilaq on the case body to make sure it does not overheat, and use some 700 degree Tempilaq on the neck to make sure it reaches the required temperature. It's not worth the risk of guessing.

[dyst0pia]

I appreciate the pointers, but there seems to be a bit of confusion as to what exactly I built here. There is no flame; the brass sits inside a coil of copper tubing. As such, I'm not sure I need a turntable. The smoke is from the Tempilaq; clean cases don't do that. Ignore the blue LED fan; it was the only one I had lying around, and I didn't want to buy a new one



I'm looking for consistency, which is why I built this thing instead of going with a torch and pan (or drill). What I was really asking for was help on "reading" the Tempilaq, as I was unclear as to how much perceived change to the liquid signifies an indication. But it seems that the answer to that question is "any".

[Metal God]

Yes any change in the higher temps are the indicator . Placing the tempilaq inside the neck is still what you need I'd think . The heat has to pass through the tempilaq before it heats the case . This should still cause the tempilaq to change before the neck is completely to temp . I'd also think you could look down into the case necks and watch it change to get the timing down better . Not sure on that just thinking out loud .

And yes I did not see the annealer you made , sorry about that

[dyst0pia]

I did put Tempilaq on the inside of the neck; it turned at the same time as the outside. The heat actually comes from the brass itself, not the coil, so if anything, the Tempilaq might change too late rather than too early. The timing is controlled electronically, adjusted by a trimpot on the breadboard you see on the left.

Anyways, thanks again for the tips, everyone. I think I'll stop worrying about being so exact and just go shoot . If I'm feeling particularly bored one day, maybe I'll test the different heatings and see what effect (if any) they have on group size.