Case color change - metallurgy question

[highplainsdrifter]

I put a number of cases in my tumbler last night, filled with water, stainless media, a little Dawn detergent and Lemishine, as usual. Unfortunately, I got involved in something else and forgot my tumbler. I woke up this morning remembering that I had left my tumbler on, so I promptly went outside, turned it off and drained it. What I discovered is that my cases, while nice and shiny, have now taken on a distinctly more copper-ish color than normal brass. I have included a side by side picture here with some copper colored brass vs. brass colored brass for reference. My question is, have I changed the metallurgy of these cases such that I should throw them away, or are they still safe to load and use?

 

[ppaul]

I'd shoot 'em. Maybe save them for a match, if you win you could have alot of fun with the losers!

 

[Hohn]

The excess lemi-shine acid dissolved some of the zinc in the surface. It’s safe. Next time, go easier on the l-s and maybe don’t soak overnight.

 

[Webster]

I put a number of cases in my tumbler last night, filled with water, stainless media, a little Dawn detergent and Lemishine, as usual. Unfortunately, I got involved in something else and forgot my tumbler. I woke up this morning remembering that I had left my tumbler on, so I promptly went outside, turned it off and drained it. What I discovered is that my cases, while nice and shiny, have now taken on a distinctly more copper-ish color than normal brass. I have included a side by side picture here with some copper colored brass vs. brass colored brass for reference. My question is, have I changed the metallurgy of these cases such that I should throw them away, or are they still safe to load and use?

You cannot change the metallurgy. The color changes with the thickness of the copper oxide. It's just a very microscopic change related to how much oxide is present. I have used Dawn and Lemishine for years.

 

[rwj]

Try placing them into a mild vinegar/water solution if the tarnished appearance bothers you...

 

[243winxb]

Dezincification of cartridge brass on the surface. Use extra lube when sizing.
Load & shoot.

No vinegar.

 

[dolek]

I have never left mine soaking overnight, but have seen the same thing on certain brass . They are good to go

 

[Dusty Stevens]

The citric acid dissolved some of the metal. Who knows how much and how deep from the inside. Cant believe some of the responses knowing this forum like i do.

 

[highplainsdrifter]

The citric acid dissolved some of the metal. Who knows how much and how deep from the inside. Cant believe some of the responses knowing this forum like i do.

Dusty, would you advise scrapping them then?

 

[243winxb]

When brass corrodes, it can undergo dezincification, a process in which zinc is lost and copper is left behind. Mild dezincification may simply cause a cosmetic change, namely, the colour of the surface turning from yellow to pink, but severe dezincification can lead to the weakening of brass and even its perforation.Jul 22, 2019

https://www.canada.ca/en/conservati...on-institute-notes/dezincification-brass.html

 

[Webster]

Dusty, would you advise scrapping them then?

Now Dusty is a metallurgist expert in corrosion . 16,000 expert replies in 5 years.

16,000 replies, never once asked a question. Hummm

 

[highplainsdrifter]

Now Dusty is a metallurgist expert in corrosion . 16,000 expert replies in 5 years.

Point taken.....

 

[Dusty Stevens]

Now Dusty is a metallurgist expert in corrosion . 16,000 expert replies in 5 years.

What makes you think im not? Then we ask what makes you the expert? I did work at one of the only thixocast facilities in the world, solving metallurgy issues on a daily basis as an engineer at the same table. If cartridge brass loses its zinc does that make it stronger or weaker? We dont need scooby doo to solve this mystery. But we’ll let you, the expert, tell mr highplains drifter that his brass is fine and safe for him to use.

 

[Dusty Stevens]

50,000psi of hot gas leaked out! Its ok, some guy named “webster” said it was fine.

 

[243winxb]

I wonder? Measure neck wall thickness with a ball mic. Same lot of brass. One washed to long vs normal wash.

Did the steel pins thin the necks? Or the chemicals?

Just thinking out loud, while trapped in quarantine.

When in doubt throw it out.

 

[highplainsdrifter]

https://www.canada.ca/en/conservati...on-institute-notes/dezincification-brass.html

View attachment 1171876

243, I read the article that you have quoted. I took one of the cartridge cases and lightly scraped the surface with a steel straightedge. The discoloration appears to be just on the very surface of the brass as in the area I scraped there is a shiny brass color showing through. Thank you for the article.

 

[highplainsdrifter]

50,000psi of hot gas leaked out! Its ok, some guy named “webster” said it was fine.

Dusty, I'm just considering different opinions on this and have not made any decision. I appreciate your comments and your expertise. My inclination is, if in doubt, throw it out! However, I am also a little bit inclined to load some low pressure loads to see how one or two react just as a learning exercise. Would you definitely throw them out at this point?

 

[dolek]

Just a guess,but thinking the inside looks similar to the outside . I have seen this same thing and a quick round in the tumbler brings it back to normal so I was very confident in using it...and that was about 10 reloads ago

 

[Dusty Stevens]

Dusty, I'm just considering different opinions on this and have not made any decision. I appreciate your comments and your expertise. My inclination is, if in doubt, throw it out! However, I am also a little bit inclined to load so low pressure loads to see how one or two react just as a learning exercise. Would you definitely throw them out at this point?

No, i wouldnt, but i cant in good conscience tell you not to. Dale makes a good suggestion above- i have done that as well

 

[highplainsdrifter]

I wonder? Measure neck wall thickness with a ball mic. Same lot of brass. One washed to long vs normal wash.

Did the steel pins thin the necks? Or the chemicals?

Just thinking out loud, while trapped in quarantine.

When in doubt throw it out.

I will run that test, 243, thank you. I have to run up to my Ace Hardware store or Harbor Freight (gulp!) to pick up a ball mic. Been needing one anyway! Gotta find my mask and gloves! I have just awakened to the adventures of playing with neck thicknesses and do need more tools to fully appreciate the differences in neck pressures. Thank you....