Did I just ruin my brass? Put it in the oven...

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Tomekeuro85

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Oct 11, 2007
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#1
So this is my second time using the Stainless tumbling method.. the first time I put it in the oven to dry it and the brass came out shiny and dry.

This time I put it in the oven at 290F for an hour, and the brass came out pretty dark and tarnished looking. Each piece of brass also has that "oil rainbow-ish" look to it.

At what temp does annealing become unsafe for the head area?

My concern is that I inadvertently annealed the entire casing.. but I didn't think 290 would do it. I'm mainly worried because of the drastic color change and the rainbow hue. They were shiny as new when they went in there, perfect visually.
 
#5
Re: Did I just ruin my brass? Put it in the oven...

I wouldn't trust it. Just because you set the thermostat to 290 doesn't mean the brass didn't get hotter. Over the last year or so every post I've seen with a title similar to this one involves someone putting brass in the oven. If you want it to dry faster I'd suggest a heatlamp.
 
#7
Re: Did I just ruin my brass? Put it in the oven...

After I pull the brass out of the wet tumbler, they are all shiny. I lay them out on a towel and roll them around to dry the outside, mostly. Then I shake them a bit to get any liquid from the inside possible, but I dont work on it too hard. Then I just throw them into my fine ground walnut media and vibrate them for an hour or two. Drys them off and keeps the shine on em this way.
 
#9
Re: Did I just ruin my brass? Put it in the oven...

The rainbow "oiled" look is due to hard water and/or an incomplete rinse of the detergents IME.

I oven bake my brass at 200F (I slowly turn the dial until I hear the relay click "on" to heat) but 290F is well below the temp needed to anneal brass in an hour, or even a month.

Brass anneals on a logarithmic scale

1yr at 290F (maybe?)
20mins at 400F
60s at 500F
10s at 650F
3s at 800F and it's probably ruined

The average kitchen appliance oven or toaster oven uses a "bang bang" control system. This (simplified greatly) means that it goes "on @ 100%" and then "off" as it hits the temp. Then it cools, then "on @ 100%" then off. This causes a sinusoidal pattern to the Temp vs. Time trace and you get varying temps during the cooking time that may range up and down as much as 50F on the surfaces closest to the heating elements.

So, that means your 290F could have been as much as 240-340F, but thankfully the high end of that is well below the critical temp and time alotment for ruining the work hardened brass case head's integrity.

In the future do this:

Set the oven just until you hear it "click" the relay on for heat (or until you hear the gas start and whooosh in a gas oven)

Rinse the brass an extra time an pat it dry on a papertowel or clean rag before baking it.
 
#10
Re: Did I just ruin my brass? Put it in the oven...

tsar-bomba4.jpg
 
#11
Re: Did I just ruin my brass? Put it in the oven...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: blklabs</div><div class="ubbcode-body">Try the press test. Press the lip of the case against a hard surface, if the case collapses easily then the brass is ruined. </div></div>


I tried this and compared the same pressure to known good brass.

Both took the same pressure to make the same size dent in the neck, which btw was not much pressure at all.


I found one piece that i forgot to put in the oven with the rest of them... this one is still perfectly shiny
 
#13
Re: Did I just ruin my brass? Put it in the oven...

I agree that you weren't at a suitable annealing temp. I have dried in the oven as well, but generally set it at 175F.

Also consider a towel dry, then the refridgerator. It does a nice job of drying things out, but will create a little condensation when removed.

Those are some fancy billet loading blocks! I use hunks of 2x4 I drill holes into.

Anyone have a link to a "drying box"? I've been thinking of making one of these.
 
#14
Re: Did I just ruin my brass? Put it in the oven...

I honestly doubt there was enough heat to do serious damage. I think the proper temp for annealing is probably somewhere above 600 degrees. I would watch the primer pockets after firing to see if they are growing abnormally fast.

Greg
 
#15
Re: Did I just ruin my brass? Put it in the oven...

Seems that the general consensus is that the temp wasnt high enough for long enough. What I'll most likely do is take just one piece with me and shoot it and see how it works. If it's ok then I'll load up the rest.

The brass is a winchester/ RP mix of .223
 
#17
Re: Did I just ruin my brass? Put it in the oven...

Assuming OP's brass was at risk of being fully annealed, is there any way to rework the brass to save it (assuming the brass is e.g. Lapua and worth saving).

I thought maybe you can load them up with very weak loads with no bullet seated and firing them in a manner similar to how your fire-form brass. That way the brass expands a little when fired and hopefully starts to be "rework" hardened.
 
#18
Re: Did I just ruin my brass? Put it in the oven...

LOL @ Treebasher !!!

Tom,

Try crushing the web of one of the cases some pliers. It should be very hard to crush and may not even crush at all, if its a .308 case... small cases may be different.

Next time just use alcohol to dry them up. Buy 2L of metho spirits from you supermarket and use that. I put the cases and metho/ethanol into a container, swish them around for 30 second and then pour the liquid back into another container. Hit the whole lot with a hair dryer and within 10 minutes everything should be as dry as it can get.
 
#19
Re: Did I just ruin my brass? Put it in the oven...

I believe it is just insufficient rinsing, or too much gunk for the water. I had the same problem using ceramic media.

For drying, I use an old food dehydrator that was laying around gathering dust. I towel off the brass first, as this reduces water spots. Then I just pile it in the dehydrator and let it run.

For tall brass that I want to be extra clean, I took one of the dehydrator layers and cut out the intervening ribs. This gives me an extra high open layer.

ss4.jpg
 
#23
Re: Did I just ruin my brass? Put it in the oven...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tomekeuro85</div><div class="ubbcode-body">So this is my second time using the Stainless tumbling method.. the first time I put it in the oven to dry it and the brass came out shiny and dry.

This time I put it in the oven at 290F for an hour, and the brass came out pretty dark and tarnished looking. Each piece of brass also has that "oil rainbow-ish" look to it.

At what temp does annealing become unsafe for the head area?

My concern is that I inadvertently annealed the entire casing.. but I didn't think 290 would do it. I'm mainly worried because of the drastic color change and the rainbow hue. They were shiny as new when they went in there, perfect visually. </div></div>

Do you sell the loading blocks?
 
#26
Re: Did I just ruin my brass? Put it in the oven...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">yes he does Cactus </div></div>

Thanks VMAN!
 
#27
Re: Did I just ruin my brass? Put it in the oven...

Build yourself a drying box. Get a steel ammo can, axial fan, lightbulb, and chickenwire. I have been using mine for almost 2 years now. Dries all the brass in about 2 hours.
 
#28
Re: Did I just ruin my brass? Put it in the oven...

Dont you have a heat vent in your house? I put mine over one and it works great. I just use a wire basket so I can get air flow. My basket also is used for my mail. its 3 in off the floor and never been a problem
 
#29
Re: Did I just ruin my brass? Put it in the oven...

An update for everyone, I used all the brass and it worked just fine, no problems whatsoever.

The only thing was that it was a bit harder to get the primers in than ususal.

Shot just fine great groups too. Must have just been stained.
 
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