Any ideas on how to clean steel shot that sat in a rotary tumbler? I
didn’t use my tumbler for 2-3 months and obviously should’ve drained
it. I just strained the steel shot and rinsed it several times but
it is leaving my sterling silver looking like brass. I can only
assume that it is coating the silver with rust even though the shot
appears clean, as does the water it is in. Do I have to buy new shot
and if so, who do you all like to buy from? Also, I would love a
suggestion for an abrasive take down. My apologies if this has been
covered extensively in the archives and will do a search to see.
Happy Holidays.
Sherri Strandberg
Illinois–where freezing rain has come way to prematurely
Tumble it in a solution of washing soda (soda ash sodium carbonate)
should be in the laundry soap area of a good well stocked grocery
store. Then ALWAYS store steel shot under a the same solution. Steel
likes to be in a basic- alkaline solution out of the air.
Sherri - the simplest answer is to buy stainless steel shot and you
will never have to deal with this again. You are supposed to be
making pretty stuff, not using up your life figuring out how to get
steel to stop doing what it does very well - rust. Just call it a
lesson learned very well.
I think that if you soak the shot in ammonia the rust will
disappear.
Nope. Not unless it’s so loose that it floats off. Ammonia doesn’t
dissolve or attack oxides, and rust is iron oxide. Simply running
the tumbler with almost anything like a wetting agent or cleaning
agent, soap, or ammonia, or just water, or perhaps even dry, will
mechanically abrade and thus remove rust. But only on exterior
portions of the shot exposed to the action. The solutions simply help
to rinse away the removed oxide residue. If you want the solution
itself to be actually helping remove the rust, you need something
other than just ammonia.
Acids, however (ammonia is a base), in many cases do dissolve oxides.
The trick with rust is to find an acid that attacks/dissolves iron
oxide, while not attacking the iron itself. With copper oxides, for
example, sulphuric acid or it’s salts like we use for Pickle dissolve
copper oxides easily but attack copper itself only very slowly. For
iron, though, nitric, hydrochloric, or sulphuric acids all readily
attack the iron too, so removing rust with these can damage the still
healthy metal as well as dissolveing the iron oxide. However,
phosphoric acid doesn’t much attack the iron, while it does attack
the rust. Phosphoric acid is the componant in Coca Cola that cleans
up the rust. Putting it in your tumbler combines the chemical
dissolution of the rust by the acid, with the mechanical abrasion of
the rust by tumbling. And the tumbling will help to slightly smooth
and burnish the shot itself, so roughness on the steel surface left
by the rusting process will be reduced. Without that, the shot may
end up without rust, but it will be abrasive, not just a burnishing
agent.
Answer: Yes, but you may have to replenish the Coke periodically.
It’s the phosphoric acid that does the trick. I always use the diet
Coke - not sticky.
Judy’s right about buying and using stainless steel shot; it will
solve the rust problem. But take care in what you buy as stainless. I
recently bought some from an ordinarily reliable supplier. I left it
in the tumbler a couple of days without use and came back to it to
find a significant amount of rust. Curious, I got out a magnet - and
about half of the shot could be picked up. When I took it back to
the supplier, they averred that it was “low grade” stainless. They
took it back & I bought the more expensive product from Rio which I
had previously used. Something about getting what you pay for, I
guess.
sometimes it is funny to read the answers of others for the same
subject. One says “no” another one answered “yes” and even a
"probably" is found in an answer -))
Just a small remark and nothing personal. Don’t be upset by this
mail…however, it is funny.
I’ve heard of people using coke and other sodas that contain
phosphoric acid to remove rust from ferrous metals. It’s just about
as easy, and faster, to get Naval Jelly. It’s active ingredient is
the same phosphoric acid.
A note of caution, if you your polishing media gets more than
surface rust that is easily wiped off it is going to scar the surface
to some extent. Once that happens you’ll have abrasive media unless
you tumble it with other abrasive media to bring it to a polish once
again. Check it with a loupe before you use it for polishing precious
metals.
Curious, I got out a magnet - and about half of the shot could be
picked up.
Just a warning - magnetism is not a good test for stainless. Some
stainless steel alloys are magnetic, some are not. It depends on
whether the alloy has nickel. Some are more corrosion-resistant than
others, too.