Citric acid brass cleaner

[PeterAnderson]

Hi Guys

I am new to this site from the UK and this is my first request - please be kind -.

I have read every post on this excellent thread and I have one question to ask. I have an ultrasonic cleaner [looks the same as the Hornady one] with a stainless steel tank; if I put my once fired cases into the plastic tray with a fresh batch of citric acid - will it tarnish the tank. OR is it better not to use the ultrasonic and do it in the hot water mix, then use the ultrasonic after a rinse. Lastly is it a good idea to use bicarbonate of soda in the rinse process.

Thank you

[AggieEE]

Welcome to the site PeterAnderson, I got a nice welcome here a few months back so I'll pass it on. You are on the right track about using a basket with your ultrasonic cleaner. The citric acid should not tarnish your tank if you don't leave it in forever. If you rinse the brass three times I don't think you would need the bicarb. To blow my own horn, go to special projects and search for " care and feeding of your ultrasonic" I tried to answer all of the questions I've been asked about ultrasonics. If you have any questions please ask.
AggieEE

[sagacious]

Peter,
AggieEE has answered your query exactly as I would have. The citric will certainly not tarnish the stainless. The bicarb in the rinse is not needed, due to the special nature of citric acid. Good luck!

[Typecaster]

Cleaning JHPs w citric acid?

Now that Southern California is getting a little rain, it's time to neaten up the gun room. I found a BUNCH of gifted J-work bullets. The FMJs and JSPs went to a friend with a new case tumbler for him to get some practice, but there are at least 1,000 .224 hollow-points with a lot of "character" (read: tarnish). I'm leery of getting media stuck in the hollow point, so I'm planning to give them a citric acid bath instead. Then I can box 'em and keep cleaning up.

What a neat product!

Richard

[MakeMineA10mm]

sagacious,
Thanks for this idea. I have some brass that is really grungy and I have tried the vinegar without any success. Those are 45ACP cases that got wet and were not dried immediately and stored in a plastic bag, which let it corrode pretty badly...

For now, I'm testing out this citric acid bath idea with some 30-06 cases from military pull-down ammo. It looks like 1945 production, and even though it was never fired, it has some black nasty stuff around the necks and shoulders that I want to get rid of.

I couldn't find perfect 100% citric acid, so I bought some sugar-free Crystal Light natural lemonade. It's main ingredient is citric acid but it also contains (in order of quantity): potassium and sodium citrate, aspartame (phenylketonurics), magnesium oxide and less than 2% natural flavor, lemon juice solids, acesulfame potassium, soy, lecithin, artificial color yellow #5, and BHA...

I followed your directions to the letter, and I did not get the instant, noticeable improvement. I also noted someone else had used sugar-free kool-aid, and mentioned that it had to set longer, so I'm trying that. But I wonder if there's something in this lemonade mix that is preventing it from working properly??

(So far, I'm kind of dejected -- Vinegar was a no-go, and now citric acid doesn't seem to be working so great... Maybe I'm doomed to ugly brass... )

[Molly]

>For now, I'm testing out this citric acid bath idea with some 30-06 cases from military pull-down ammo. It looks like 1945 production, and even though it was never fired, it has some black nasty stuff around the necks and shoulders that I want to get rid of.

I suspect this is asphalt. Asphaltics were (and I think still are) used for water-proofing a round. If so, you’ll play hob trying to get it off with ordinary cleaning solutions, but it should come off easily with a bit of lamp oil or lighter fluid on a rag.

>I followed your directions to the letter, and I did not get the instant, noticeable improvement. I also noted someone else had used sugar-free kool-aid, and mentioned that it had to set longer, so I'm trying that. But I wonder if there's something in this lemonade mix that is preventing it from working properly??

There’s nothing you list that should make a major difference, as long as citric is the main ingredient. If it’s present in sufficient quantity, Citric should work fine. But if it doesn’t, you might try doubling the amount of Citric or heating the solution a bit.

If that doesn’t work, you might want to consider my personal favorite, phosphoric acid. Like citric, it is non-toxic and you can pour it down the drain when you’re done. And it's in the soda pop you drink. Buy it at any chemical supply store or at your local hardware as ‘Naval Jelly’ Heat up a gallon of water until it’s uncomfortable to stick your hand in. The solution will work much better if it’s warm, but you can use cold water just about as well. Then add a small squirt of momma’s dish detergent and stir in a two or three tablespoons of the acid, whichever you were able to find. Now toss in your deprimed cases and watch it work – if you can. I’ve seen some grungy cases look almost new before they hit the bottom of the jug. Yet you can leave the cases in for days without any harm.

Really bad black cases will often have a reddish tinge to them when you take them out. This is just a lightly adherent copper dust that is left when the black oxide has been removed. I like to drain my cases and tumble them back and forth in a big bath towel to remove excess water. This will also remove most of the copper dust, if there’s any there. Finish by drying overnight. If you’re in a hurry, spread them out on a cookie sheet and pop them into the oven at about 125 degrees, or ‘warm’ setting. They’ll be dry through and through in a hurry.

Use the lighter fluid first though. Phosphoric won’t dissolve asphaltic compounds any better than Citric will.

Hope this helps.

[MakeMineA10mm]

Thanks Molly!!

[MakeMineA10mm]

Well, I have been processing 1000 mil-surp (pull-down) 30-06 cases I acquired from Bartlett about 10 years ago. It is headstamped "L C 5" and is fairly grungy. As you can probably surmise from my previous post, the Citric Acid didn't seem to do much for me. I'm not sure if that's still the case or not... I wanted the passivation aspect, so I processed all the brass the same way and did not save out any to try processing purely with tumbling. But, I will say this - the few cases I tried tumbling, before remembering this idea from this thread did not clean up during the initial tumble. In fact, finding some of the blackest grunge on there in the neck-shoulder area is what made me ponder and remember this thread. After running them through the bath and re-tumbling, the grunge was gone. I guess what I'm trying to say is, I did not get the results that sagacious did, but it still helped greatly. In his early posts on this thread, he showed a pic of a 50-cal case that he dipped into the citric acid and the dipped part is sparkly, while the undipped part is still grungy. Well my brass still looked grungy after the bath! But, they did polish up better in the end than if I hadn't used the citric acid bath, so I'm still pleased.

Here's my process:

Put a stock pot with about 2 gallons of water on the stove and got it up to boiling. Got out a plastic storage tub that's a little bigger than a shoe box. Poured in a half-packet of sugar-free Crystal Light lemonade (mainly made up of citric acid), and then after the water was boiling hot, poured it into the plastic shoebox about half-way. Then, stirred the water/acid with a plastic spoon.

Next, I poured in about 200 cases and let them sit. Tried stirring the batch with the plastic spoon and putting the plastic lid on the box and sloshing it around, but the agitation didn't seem to matter. Let them sit in the bath for varying lengths from 10 minutes to 40 minutes. Again, length of time didn't seem to matter, though I got slightly better results at 15 minutes or more.

Carefully, I poured about 90% of the water-citric acid mix back in the stock pot and got it heated again. I didn't worry about getting it fully to a boil, because even at a boil, the cases were still grungy after the bath, so I figured max heat wasn't that critical. For further batches, I just made sure the water-acid mix was hot enough to be letting off steam from it's surface. (Way too hot to touch...)

Now the plastic shoe-box was put in the kitchen sink under hot running water and the cases were rinsed twice. Then, dumped them into a collander to let drain. Pre-heated the oven to 200 degrees F. I shook the cases over the sink to get out large amounts of water and then used paper towels to dry the outside of the cases. Then, onto a sheet pan and into the oven for about 20 minutes. This evaporated all the water that was inside the cases and couldn't be wiped out. This temperature is way to low to effect the temper of the cases.

They were then pulled out and allowed to cool for awhile. Naturally, while 200 were in the oven drying, another 200 were back in the plastic tub with water-acid bath to soak. Got a veritable assembly line going!

Last step was to take the cases to the tumbler. I got a really good deal on Dillon's media polish awhile back and got a case of it, so corn-cob and Dillon blue cleaner were put in the tumbler along with the 200 cases and allowed to run for 4-5 hours. (This is the bottle-neck in my operation... Wish I had that second Dillon tumber still...) Yes, 4-5 hours is a long time, but I found that if I didn't run them until they were polished as bright as I could get them, there would be slight color/shine differences from batch to batch, and I'm too OCD for that. They ALL MUST look the same.

So, after that polishing, they are all bright gold and shiney. (Actually look more like commercial brass now than military...) I know that they wouldn't be that good if I hadn't done the citric acid bath, but it surprises me that I don't see the results right after the bath, but after the polishing... Perhaps the citric gets underneath the nasty stuff and breaks it loose and it's my aggressive polishing that is finally putting the finishing touch (sorry for the pun) on the process?

Sorry, I was going to post some pics, and will still try later, but I can't find the battery to the camera right now...

[a.squibload]

Put a stock pot with about 2 gallons of water on the stove and got it up to boiling...
Poured in a half-packet of sugar-free Crystal Light lemonade (mainly made up of citric acid),...

How big is a packet of Crystal Light?
I think the "recipe" calls for 2 tsp acid / quart,
or 3 tbsp / gallon (is that right someone?).
Hope you are using enough acid.
The solution can be re-used several times.

I use really hot tap water and it works great, only takes a few minutes
to notice it's done.

[MakeMineA10mm]

How big is a packet of Crystal Light?
I think the "recipe" calls for 2 tsp acid / quart,
or 3 tbsp / gallon (is that right someone?).
Hope you are using enough acid.
The solution can be re-used several times.

I use really hot tap water and it works great, only takes a few minutes
to notice it's done.

Hey, that's a good point, squibb! I found the bigger packets that are designed for a pitcher of lemonade. They weren't marked as to weight on the indivdual packets, but the entire can was 3 oz and there were 5 packets... So, it probably was a little light on the amount. I guess I missed the concentration part and kept reading the "concentration" or "quantity of acid concentrate" doesn't matter... Looks like I was using well under a half-ounce for a little over a gallon... I'd say it did work, because the water was pretty green by the time I was done, and the brass did all clean up, but maybe this low concentration is why I didn't see the near-instantaneous action like sagacious reported on??

[a.squibload]

Yeah, it was working but S L O W.
Don't know how much Crystal Light costs, I bought citric acid in a ziploc bag online
for a few bucks, enough for many batches.

I even used it on an old oil lantern, softened up a lot of rust that I wiped off.
I made a weak concentration, will try it again, then patch the rust holes I didn't see
before I bought the dang thing!
OK, it was only $4, the glass is worth that.

[MakeMineA10mm]

Yep, I agree. I'm going to take another whack at those 45ACP cases, this time with citric acid.

The vinegar, if I left the cases in it long enough, did get rid of the black "scab" on the cases where the corrosion had begun, but the brass area underneath was a reddish-brown color. Almost like it was rusted brass that had been chemically changed somehow by the vinegar?? I've still got a bunch of those cases with black on them, so I'll try the citric on them, but I'll also try the ones that did clean up with the vinegar, and see if the passivation action of the citric minimizes that reddish-brown discoloration. I might save some or most of these cases after all... (I have almost written them off, but we'll see...)

And, this time, I'll be using at least a full packet of crystal light!

[felix]

The objective is to eliminate oxides from the cases. When the cases become reddish, that means the zinc within the metallic matrix itself was soluble without regard to the metal being an oxide or not. Higher the temp, and the quieter the agitation, the more of the most-soluble metals are going into the liquid solution. The zinc is less soluble in citric and/or phosphoric acid than it is in vinegar, or other more available acid, waters. ... felix

[MakeMineA10mm]

The objective is to eliminate oxides from the cases. When the cases become reddish, that means the zinc within the metallic matrix itself was soluble without regard to the metal being an oxide or not. Higher the temp, and the quieter the agitation, the more of the most-soluble metals are going into the liquid solution. The zinc is less soluble in citric and/or phosphoric acid than it is in vinegar, or other more available acid, waters. ... felix

Thanks Felix! Just so I'm clear, does this mean, on those black and red 45 cases, I should be using cooler water with the citric acid and agitating them as much as possible?

I presume I still need to get the water over a threshold temperature [I thought I heard 140-degrees?] to get the citric acid dissolved and working properly?? Could I do that to dissolve the citric acid and then let it cool, to reduce the problem of zinc solubility?

Or, are you saying the cases with red areas are "done" and the vinegar did the job, but left some discoloration from the zinc dissolving, and there's no need to continue processing them?

[Molly]

The objective is to eliminate oxides from the cases. When the cases become reddish, that means the zinc within the metallic matrix itself was soluble without regard to the metal being an oxide or not. Higher the temp, and the quieter the agitation, the more of the most-soluble metals are going into the liquid solution. The zinc is less soluble in citric and/or phosphoric acid than it is in vinegar, or other more available acid, waters. ... felix

I think you are ALMOST right Felix. Zinc oxide is dead white. Copper (II) oxide is dead black. The color of tarnished cases is almost entirely due to copper oxide. While some zinc oxide may form, it is not a primary pigment (ie, it doesn't cover or hide very well) and will be visually overpowered by the Copper (II) oxide.

Both black copper (II) oxide and zinc oxide are acid soluble. However, the first reaction is to reduce black copper (II) oxide to red copper (I) oxide, which is the reddish dust often found on acid rinsed tarnished cases.

Recall that brass and bronze are VERY corrosion resistant: That's why they were the preferred metals on wooden sailing ships. Citric, phosphoric and (dilute) acetic acids WILL dissolve the base metals, but VERY slowly. An interesting test would be to make up a small quantity of each at the same molarity, and drop a fired .22 case in each to see how long it takes to dissolve them.

[felix]

No argument, Molly, because you are correct. Zinc is far more soluble than copper and that is a problem for what we are doing. We tend to overdo everything to do it faster, or do it mo'betta'. Here is a situation where moderation should be maintained. The real nasty black case SPOTS, per MMA10's post above, is to just spin the cases and "detox" them with 0000 steel wool. Quite frankly, I don't do any of it because I'm ONLY interested on how they shoot and absolutely nothing else. I wash cases every time, though, with constant agitation in cold solvents, like cheap paint thinner and reuse the latter when it has enough "lube" solids to "wash" freshly cast boolits to give them a hard coating (beeswax/carnauba remains). ... felix

[prs]

The last couple of times I purchased Prestone Super Flush concentrate, the active ingredient was citric acid.

prs

[montana_charlie]

This eBay sale gives you two pounds of citric acid powder for ten bucks, delivered.
The active ingredient is citric acid.

http://cgi.ebay.com/Free-Citric-Acid...item2c5a297173

[Centaur 1]

I'm definately going to try the citric acid, I just squirted some brass with lemon juice and they cleaned up nice. As far as getting the cases dry again, a trick that I learned is that alcohol absorbs water and dries much, much quicker than plain water. After rinsing your cases well with water, put rubbing alcohol in a bowl and your brass in a strainer. Dip the strainer in the bowl and shake it a bit, then lift it out of the bowl and let the alcohol drain for a few seconds. Now you can spread the cases out on a baking pan and place it under a heating vent in the winter or out in the sun in summer.

[onesonek]

Just tried the citric acid myself,,,,totally amazing!!!!

I got a line on it for $2.00 per/lb.... If you guys want, I can set up a group buy at that price plus shipping to you. I think the $10.95 flate rate box would hold 20 lbs. if not more.
Likely 2 lbs in the small $5.20 FR box