Brass discoloration

Nick_C_S

New member
I'm new to SS pin tumbling. With some of my brass, I chose to oven dry. I have a gas oven and set it to 220f - figuring to go a little over the boiling point of water. I have an oven thermometer and the oven's thermostat is accurate.

All the brass I oven dried slightly discolored from that normal bright yellow brass color to a tawny, slightly orange-ish discoloration.

What happened? Surely the brass didn't get hot enough to anneal. They were first tumbled with water, a squirt of Dawn, and just a 1/2 of a 380 ACP cartridge full of Lemi-shine. 1lb water; 1lb pins; 1lb brass. I rinsed them really well before placing in the oven.

Air dried brass is fine. This is 38 Special brass, if it matters. Fairly new - fired maybe once or twice. Most of it - but not all - is Winchester.

I'm also curious if it's permanently discolored, or if it will tumble back out. (I'm guessing it's permanent.)
 

Wreck-n-Crew

New member
They will tumble back out. I have done the same thing. I try not to use the oven but when I get busy I just set it on 150 degrees or some ovens it is the warm setting. Some may only go as low as 180.

If your batches are not that big it is faster to shake them out good with a strainer, spread them out on whatever your using to oven dry them and use a hair dryer and blow dry them while shaking them around here and there.
 

Rondog

New member
I dry mine in the sun, but I've found that if I spread them out wet they'll tarnish so fast I can almost watch it happen.

After I rinse them real well, I dump them on a big cotton towel and blot them real good with another cotton towel. Cotton is the most absorbent, don't bother with any synthetics. And worn-out cotton towels are even more absorbent.

After blotting, I spread them out on a big movers blanket on the patio. Again, cotton! Synthetics won't absorb water, it'll pool up under the brass and tarnish will happen.

FWIW - I use a small cement mixer and run 25lbs of SS pins and 20-25lbs of brass. So I'm running fairly large amounts.
 

LE-28

New member
Drying in the sun is definitely the best if it ever shines again. Through the summer I use the sun more than anything but in the winter I put mine under an inferred ceiling heater I have hanging 18" above my work bench in the garage.

They tarnish drying them that way also. I use spray case lube in my auto progressive press with my 9mm and .357mags so for me it's a given that I throw them in my rotary tumble and dry tumble them for about 20 minutes after their loaded. That takes the lube and tarnish off in short order. I have some New Finish or something mixed in also.

Heat drying of any kind seem to accelerate the tarnishing.
 

Gdawgs

New member
I also do the towel/air dry method. I use a fairly large towel, put the brass in, then fold the corners of the towel together to form a sort of bag. Then I give the whole works a good shaking. This helps get a lot of the water out of the insides of the cases as well as the outside. Then open up the towel and spread everything out to dry.
 

Nick_C_S

New member
Like rondog and Gdawgs, I now use an old large cotton towel. Yes, old towels (that haven't been impregnated with fabric softener) definitely absorb better. I do the "fold into a bag and shake" method, followed by laying them out on the towel in a warm room upstairs (I'm in California, so humidity is never a problem). I'm having the best luck this way; and so, I think I'll continue.

Once again, the collective minds of TFL come through. I think this post has already answered my question: Heat tarnishes brass. I didn't realize that. And this is the sort of thing I should have already known, given my background.

It's also good to know that the tarnish will tumble off.
 
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