Case Dicoloration

[SirMike1983]

I ran some brass through my Lyman heated ultrasonic cleaner yesterday. The first couple boxes of brass came out nicely. The cleaner's water was hotter by the time of the third box. I got some blue-purple discoloration on some of the cases. The water was hot to the touch and steamy but not boiling or bubbling. It seemed about like hot dish water. The solution was the NRA type water, vinegar, dish soap, and salt mixture.

I am a bit unhappy with the discoloration of the cases, but also find it hard to believe that water got hot enough to soften the brass. The cases are Federal and Winchester brands. Is this just a cosmetic reaction of getting a little too hot in the cleaner?

The shot on the left is with no flash, on the right with. Same sample of cases. These are the worst of them.


159086159087

[Wayne Smith]

Not hot enough to harm the brass if you could put your hand in it! Does the discoloration rub off? Maybe my monitor but it looks pink to me.

[dudel]

Water didn't get as hot as the case after firing. I doubt you could soften the brass with a heated cleaner.

I've seen that happen before, and I seem to recall, that's related to impurities in the brass. Did you have any steel cases in the batch?

[SirMike1983]

Water didn't get as hot as the case after firing. I doubt you could soften the brass with a heated cleaner.

I've seen that happen before, and I seem to recall, that's related to impurities in the brass. Did you have any steel cases in the batch?

No- just brass .38 spl cases. The coloring does not rub off. The cases darkened a bit and some gained a purple-blue tint. The water was hot but not boiling. The heat really seems to help clean the brass. The box I did before this came out very clean and shiny. Apparently I let the heater run a little long and the next box developed the weird colors. Both were Federal brand brass.

Edit: it does rub off if I use a rag, some One Shot, and some effort. Could just be the way the NRA formula acts with some heat.

[Motor]

SirMike, I've seen this before on the reloading forum on AR-15.com

A lot of those guys are into "high production" and use all sorts of cleaners. I'm sorry but I can't remember what the cause was.

It may even have been something in the tap water. If you post your question over there I'm sure you will have your answer soon.

Motor

[RugerFanOH]

Try SS pin tumbling with Dawn and citric acid

[gpidaho]

My Lyman sonic cleaner sometimes discolors the brass when using the Lyman cleaning solution. Looks sort of like case hardening on steel. I can't see that it hurts the brass any, just looks different. Gp

[JWT]

I have gotten this with RCBS case cleaner and tap water. They shoot fine.

[SirMike1983]

My Lyman sonic cleaner sometimes discolors the brass when using the Lyman cleaning solution. Looks sort of like case hardening on steel. I can't see that it hurts the brass any, just looks different. Gp

That's exactly what it reminded me of- color case hardening. It had the same sort of blue-purple, mottled color. The heater was not quite as warm with the other cases I did, and they came out fine. I was concerned that these were different, but skeptical that hot water could change the hardness or softness of the metal. I guess others have seen this, and it's a cosmetic matter.


I have gotten this with RCBS case cleaner and tap water. They shoot fine.

It could be the heat, the tap water, or both I guess. Glad to hear they shoot well. This brass was pretty good and I really did not want to waste it.

The heat really does make a difference using the NRA formula. The first set of cases I did had water that was not really hot: just a bit warm. They cleaned up OK. However, the later sets with the hotter water really came out a level better. They shined up a bit too. It's not tumbler-level shine, but it's quite clean and certainly satisfactory for me.

[Wayne Smith]

The first pic looks pink - that is what happens when the zinc is leached from the brass leaving soft copper rather than brass. If it wipes off it is only a surface phenomona, if it doesn't it weakens the brass greatly. Those need to be tossed, if it doesn't wipe off.

[omegatacticalsupply]

Try SS pin tumbling with Dawn and citric acid

This is all I use for cleaning my cases, and it works great. The commercial case cleaners from RCBS and Hornady sometime do this - they're also stinking expensive. Dawn + Lemi-Shine for the win

[Geezer in NH]

My Harbor freight ultra sound did spark mark my 30-30 cases I cleaned in it. Tossed the cases and got rid of the US.

I got the Frankford rotary tumbler and now clean with pins, hot water, Dawn detergent and a 1 teaspoon of citric acid with an added 1 liquid ounce of car wash and wax.

[hunter49]

I'm in agreement with Wayne Smith on this one. Although I thought the leaching of zinc from your brass cases caused the brass to become brittle and weakened significantly. At the time you removed your cases from your cleaning solution if it was blue I would be concerned.


I see your edit where the discoloration seems to be wiping off, hopefully your cases will still be safe to shoot. I learned the hard way when I overcleaned my brass in a vinegar cleaning solution and they all turned pink. I threw them away just to be safe. Definately interested at what others have to say.

[EDG]

Quit using that silly NRA formula. It did the same thing for me 45 years ago. Not only that but your cases will start turning dark within few weeks and will look like they were never cleaned.

Spend a few bucks on the commercial product Brichwood Casey case cleaner and use it warm in a pyrex pan or dish on a hot plate.

This product has benzotriazole. The acid in the case cleaner cleanes the brass and benzotriazole protects the surface from tarnish and corrosion for years.

Here is a white paper on the subject - notice Birchwood Casey is not mentioned but the effective ingredient for protecting your brass is.

http://www.copper.org/publications/pub_list/pdf/a1349.pdf