Citric acid and brass

[swampratt]

Brass is an alloy of metals primarily copper and zinc for the common brasses (roughly 70% copper 30% zinc. Using Citric acid on Brass dissolves a minute amount of the metal (don't worry it won't hurt it), but the dissolved copper can re deposit (the zinc doesn't) back onto the surface of the brass, giving a "salmon pink" coloration. This is such a thin layer that it can easily be cleaned off.

Now when you clean with more than 1% citric or leave your brass in the solution too long you may see the pink salmon color.

Back off the time or back off the citric acid, or do both.
That is another debate on time left in solution..some say time does not matter as it reaches a certain point then stops..

I experimented with my tumbler and how much citric and how long.
I have stopped at 1/8 teaspoon for 1/2 gallon and 1.5 hours or less.
Then i rinse 5-6 times with hot water then tumble once more with just hot water and soap
for about 15-30 minutes...Rinse well 5 times or so
Brass is much cleaner.
Done in less than 2 hours total.

The bluish color you see in the water is from dissolved copper compounds…put an iron nail in it and see what happens!

Another note is that copper and zinc are toxic to the bacteria in your septic system and you know you need that bacteria in there..

Have fun!
You can search the web and read much much more on copper or brass and citric acid.

 

[aviator41]

You will also tend to get a more pink color on badly oxidized range pickup brass than you will with fairly clean brass with citric acid (lemi-shine)

Vinegar also causes the oxidation but only attacks the tarnish, leaving un-oxidized brass untouched. A combination of the two makes for a potent cleaner for range pickup brass without removing an appreciable amount of mental, but totally removing tarnish.

 

[uncle money bags]

Good info you two. I was wondering why I got the pink deposits on the brass I cleaned with Lemishine. I have since switched to using a squirt of 20% hydrochloric acid in a 2 quart ultrasonic. five minutes and its done. Not a scientific ratio I understand, but if you stay present during the process you can judge when the brass is ready. I do not recommend this procedure for anyone who is not comfortable working around acids! Also, do what you oughta and add acid to watuh, not the other way around. Then rinsed several times, first with a weak baking soda solution and then hot water.

After I shake off the water I dump the lot into a bowl of acetone to displace the water, shake them off again and let them air dry for about 20 or 30 minutes.

Total time about between 30 and 40 minutes.

 

[aviator41]

Yep, thats an excellent cleaning method. the hydrochloric acid and the citric acid essentially do the same things (as does the vinegar, which is Acetic Acid mainly). I think most people would recommend the citric acid or vinegar over using hydrochloric acid (Muriatic acid is the same thing) simply because of the its' dangerous qualities left full strength and can do serious damage to both person and property.

I use is to etch circuit boards, it will eat through copper very quickly!

I have a similar drying process, but use isopropyl alcohol instead of acetone simple because it's cheap.

I've also shot plenty of 223 with that pink hue without any trouble (in case anyone wondered)

 

[swampratt]

Citric acid will create passivation, which allows the surface of brass to resist staining by handling residues and atmospheric contaminants.
That is an upside to citric.
I have used vinegar ..but acetic acid worries me if it is not neutralized on my brass cases .
When i used vinegar i would rinse when finished with baking soda and water a few times.

I have read that acetic acid eats zinc so this vinegar deal is used sparingly if i use it at all.
Great for cleaning black powder residue though..

 

[aviator41]

Wouldn't be too worried about the acetic acid after effects. you will know very quickly if you don't have it all removed as the cases will quickly tarnish during drying. Key indicator that all the vinegar hasn't been neutralized.

A quick rinse with some water with a pinch of powdered laundry detergent, or a teaspoon of liquid concentrate, agitate for a moment, then dump the cases into a strainer and rinse them with water as you turn them over by hand.

then a dip in a bowl of alcohol and onto a cookie sheet lined with several layers of paper towels to soak up the alcohol. It's infinitely hygroscopic, leave the brass gleaming (or ready for the tumbler, either way). I've even dumped the wet brass right from the rinse onto the cookie sheet, poured alcohol over them and rolled them around, then let them air dry so the outsides don't tarnish. This works best when you know the cases are going right into a vibratory or rotating tumbler though.

 

[younggundavid]

I hadn't posted in quite sometime so I thought I would throw my own 2 cents in on the liquid cleaning discussion. About 15 years ago in Yukon, Oklahoma. There was a store called Country General. It went out of buisness and had discounted virtually everything about 30 to 70 percent off. I had just gotten into reloading back then and had been using one of the Brass Cartridge Case Cleaner solutions that they used to sell there. When they went out of buisness I bought the partial case they had left. I don't know if this company still makes it or not. That partial case has lasted me these last 15 or 16 years now. It's from a company called BRICHWOOD CASEY. It's a super Concentrate formula you just add 2 ounces per quart of water. It is a reuseable solution so it must be stored in either glass or plastic, the acid is still strong enough to eat through metal containers. I use metal lids from a half gallon mason jar and I'm replacing them constantly. (well twice a year maybe). The product states on the side.. and I quote "

Super Concentrate makes over 2 gallons of reuseable cleaning solution and will clean 8,000 medium sized cases. Easily removes resizing lubricant, oils, grime and stains from brass cartridge cases. Restores them to original finish for reliable operation. Helps remove powder residue. A safe, Non-fuming, non-etching solution that won't weaken cases.

I don't see any ingredients written on the bottle.. just warnings that the product "Contains Phosphoric acid and Glycolic acid"

Again, I really don't know if the company still makes this product or not. Actually I'm about to start my last bottle so eventually I'll need to find another ready made product to use. Knowing that this day would come I have tried different "homemade" receipes. Just hadn't found anything I felt worked as good as the Brass Cartridge Case Cleaner I bought from the store. If anyone know's wether they still makes this product or if there is another manufactured product out there similiar. I'd like to see it posted..

 

[swampratt]

Here you go buddy.
http://www.amazon.com/Birchwood-Casey-Cartridge-Cleaner-Concentrate/dp/B000LC5RB4

 

[djcorrell]

The phosphoric acid can be had easily as toilet bowl cleaner, sold locally as cherry bowl cleaner. Citric acid works as good, is less corrosive and passivates the brass. My .02. Don't worry too much about vinegar. Just stay away from ammonia.

 

[dennishoddy]

I got my first ultrasonic cleaner for Christmas, and have been using a vibratory cleaner for the last 30 years or so without any issues. I shoot a lot.

Other than visual cosmetic appearances, why clean brass? I bought mine to clean guns, but I'm not against using it for brass if its going to help the process.

Again, I am new.