Re: Stainless Steel Media Testimonials
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RoosterShooter</div><div class="ubbcode-body">I'm not trying to be a naysayer, but have a few honest questions concerning SS Media Tumbling.
1) Does anyone not remember Chemistry 101 where you put a piece of copper and brass in citric acid to watch it 'dezinc'? Could this be the reason why a lot of people are ending up with Orange or Brown cases? What about being brittle after a few cleanings? Is that not a concern?
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I'm a chemist by degree, but haven't worked in the field for some years, but I don't think there's much to worry about at these concentrations. It's probably less than a gram of citric acid in a gallon of water, plus, you need two metals with sufficient electronegativity difference for a redox reaction as you describe and stainless just ain't that active (by design) as an anode/cathode in this case. Mostly the citric acid just raises the pH slightly to "soften" tap water.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RoosterShooter</div><div class="ubbcode-body">
2) Has anyone filtered the water coming from their rotary tumbler to see how much brass is removed? A simple coffee filter will do!
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I haven't actually filtered and weighed, but I'm sure there is a measurable amount of brass particles getting rubbed off the cases as can be seen here on a freshly uncapped gasket:
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RoosterShooter</div><div class="ubbcode-body">
The reason I bring up these two points is because I have long been familiar with 'alternative' methods of cleaning brass. One of the rules of thumb is never use citric acid! Citric acid will cause corrosion of the brass and cause it to become brittle. This compromises the integrity of the 'SAAMI Spec' case!
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I just got the STM kit, but I've been using citric acid in my ultrasonic for quite some time now and I have some Lapua .308 cases on their 8th reloading and show no signs of embrittlement, etc. (I anneal every 4th firing and only collet neck size). I just don't think you're going to damage brass at these concentrations.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RoosterShooter</div><div class="ubbcode-body">
Furthermore, SS media is used in the casting industry to debur castings. I have seen it used at a local foundry, and the castings are actually cast at .010" OVER spec to allow for changes due to the media deburring process. When the casts come out they are to spec!
Again, I'm not trying to piss on the thread. I'm just looking for some serious answers and studies. "Because it works!" isn't a valid reason for me to try it. I have some serious concerns about the ways these cases are cleaned.
My main concerns are about the elasticity of the brass after several cleanings, and the pressure sensitivity after only a few firings.
Your input is appreciated. </div></div>
I've only had the STM kit for 4 days, but I'm already having serious doubts about the process.
