Ultrasonic Cleaner

[chrismetallica1]

Ok,
I finally got round to cleaning some cases with the ultrasonic cleaner yesterday. I tried a few things (flash, vinegar, cillit bang ect...) Now my question is doe these chemicals weaken or make the brass brittle at all?

chris

[lykoris]

Chris,

My understanding from everything I researched on the net before buying one is the chemical reaction that occurs with various acidic solvents used breaks down the brass on a microscopic level when it's removing primer/powder residue.

I read that guys using dry(tumbler/rock washer with a medium) and wet(ultrasonic cleaner/bath solution) didn't notice any difference in case life from using either method.

I choose the ultrasonic cleaner as it's faster and quieter than a tumbler(apartment life so it's a factor for me).

I'm going to experiment myself to confirm the above from what I've read, I plan to primarily use the tumbler to remove lubricant after FL sizing.

I've also altered the mix in which I use from the 6mmbr 'recipe' or whatever you want to call it.

at 50 degrees
20min in vinegar 80:20 with tap water
10min in Birchwood casey case cleaner
sodium bicarbonate bath for a min
rinse with hot water
and then in the oven for 10-15min at 150degrees.

I can do 300 cases in less than an hour from start to finish. I love how spotless/shiny they are when they come out

Paul

[lykoris]

I also think one is a chemical reaction and the other is like taking course sand paper to sand down the brass and in the process remove residue and cleans the case so both 'weaken' the brass.

Perhaps others would comment on this as I don't have a tumbler.



Paul

[Gun Nut]

I've used both tumblers and ultrasonic baths for several years now and haven't noticed any difference in case life. Citric acid (cheap to buy from a chemist or brewing equipment supplier) works really well in the ultrasound baths and seems to have no effect on the brass!

[chrismetallica1]

Gun Nut,
Do you use anything to neutralize the Citric acid or do you justy add a teaspoon to the US cleaner ?

Regards

Chris

[Voodoo]

A solution made from 5% citric acid and 95% warm water is chemically the same as neat vinegar, Don’t put it on chips though as vinegar is made by fermenting ethanol to produce acetic acid that’s why it tastes different but chemically it’s the same,If your water is very hard you may need to increase the amount of citric acid.

You make a neutralizing solution by mixing 1 teaspoon of baking soda (not baking powder) in 1 litre of warm water. Do a 8 minute cycle with both solutions.

The water should be hot to the touch but not boiling excessive heat makes brass brittle drying in a towel on a radiator is fine but don’t put them in the oven unless you have one with a very low setting.

Remember when you clean this way you are not only removing the dirt from the case you are actually dissolving the brass, only by microns but thats why it works.

Hope this helps

Voodoo (clues in the name)

[GillyII]

Chris,

rinse with hot water
and then in the oven for 10-15min at 150degrees.

I can do 300 cases in less than an hour from start to finish.

Paul

Sound good, Little tip DO NOT dry your cases, in the method you describe. this will cause anealing of your brass, causing the molecular structure to alter , & become more malubale..It is a NO NO !!

[rossandjet]

Sound good, Little tip DO NOT dry your cases, in the method you describe. this will cause anealing of your brass, causing the molecular structure to alter , & become more malubale..It is a NO NO !!

I think the annealing process requires considerably more heat than 150deg c

about 400+ just to relieve the stess

[lykoris]

Sound good, Little tip DO NOT dry your cases, in the method you describe. this will cause anealing of your brass, causing the molecular structure to alter , & become more malubale..It is a NO NO !!

this is a cut/paste from the 6mmbr article about annealing brass

full article here - http://www.6mmbr.com/annealing.html

Optimal Case Temperatures for Successful Annealing

Brass is an excellent conductor of heat. A flame applied at any point on a case for a short time will cause the rest of the case to heat very quickly. There are several temperatures at which brass is affected. Also, the time the brass remains at a given temperature will have an effect. Brass which has been "work hardened" (sometimes referred to as "cold worked") is unaffected by temperatures (Fahrenheit) up to 482 degrees (F) (which in celsius is 250 degrees) regardless of the time it is left at this temperature.

At about 495 degrees (F) / 257 degrees (C) some changes in grain structure begins to occur, although the brass remains about as hard as before--it would take a laboratory analysis to see the changes that take place at this temperature.

The trick is to heat the neck just to the point where the grain structure becomes sufficiently large enough to give the case a springy property, leaving the body changed but little, and the head of the case virtually unchanged.

If cases are heated to about 600 degrees (F) 315.5 degrees (C) for one hour, they will be thoroughly annealed--head and body included. That is, they will be ruined. (For a temperature comparison, pure lead melts at 621.3 degrees F).

The critical time and temperature at which the grain structure reforms into something suitable for case necks is 662 degrees (F) 350 degrees (C) for some 15 minutes. A higher temperature, say from 750 to 800 degrees, will do the same job in a few seconds. If brass is allowed to reach temperatures higher than this (regardless of the time), it will be made irretrievably and irrevocably too soft.

Brass will begin to glow a faint orange at about 950 degrees (F). Even if the heating is stopped at a couple of hundred degrees below this temperature, the damage has been done--it will be too soft.