Batteries and Rust. Kind of poetic. And this experiment is as well.
There are many ways to get rust
off metal parts. I have been using a small sandblaster that has
shot a hundred bags of sand by now, and created a small desert
between the neighbors garage and mine. [I think I saw a sandworm
in there one day.]
After all those years I was getting tired of digging sand out
of my orifices and wanted some improvement in this area.
One day I happened to link to a site that explained other ways to melt rust away, using vinegar, or molasses, or washing soda. The last one sounded interesting and the supplies were easy to obtain. That page is gone but there are many others such as; http://antique-engines.com/electrol.asp
The idea behind this method is to reverse the process used in chroming. Rust comes off the piece and plates onto a piece of scrap.
The procedure is simple. A plastic container big enough for the part is filled with clean water. Washing soda is added at about 1 tablespoon per gallon. A piece of scrap steel is suspended in the container to act a s an electrode, and both metal pieces are connected to an electric DC current. This causes the rust to come off the part and plate the scrap and/or float around in the water. After several hours the part is clean, except for a black 'soot' that has to be scrubbed off. [the soot is carbon that was in the steel and got left behind when the rust migrated.]
Like this;
This how it looked after a day in the tank, followed by a cleaning with a wire brush and soapy water.
The wiring has to go a certain
way. The Negative has to go to the part, while the Positive goes
to the electrode scrap piece. This makes the rust flow the right
way. This is also why DC current must be used. AC flows both ways,
so you wouldn't get anywhere.
The typical source is a battery charger. Preferably a 'dumb' one.
Modern chargers have circuits that detect batteries and adjusts
their current levels. A dumb one just pours it on. However, my
charger is 'smart' and it works. It just takes longer.
I attached a wire lead to the part made from house wire stripped
bare. These can be twisted tight with breaking too easily. You
shouldn't put the charger clamps in the water or they'lll gunk
up. And if you have a cut on your hand and put it in the water
you will get shocked.
After several treatments I worried
about the strain on my battery charger so a few other ways were
tried. A car battery was hooked to the part and only dropped a
few volts after several hours. Not everyone has a battery laying
around though. But I happened to have another leftover experiment
that worked great, and didn't wearout a pricey battery charger.
I had done some reading on revitalizing old batteries with electrical
circuits that zap the sulphate off, like on this page. http://members.shaw.ca/pferlow/desulfator.htm
While searching the web, I found a page with a very simple pulse
charger that used a light bulb, wall plug, and diode. Combined,
they gave a pulsing DC current that would zap old batteries back
to life, he said on his page. http://www.alpharubicon.com/elect/3dollarbattggn.htm
Well, I tried the gizmo on a battery
a neighbor had thrown out, and it seemed to make it worse, Before
it held 10V, and after several hours treatment, it held 4V. Maybe
if I continued it would have went down and back up again. However
another battery went from 0V to 3V.
So when I was into this rust removal I saw the zap gizmo lying
there and hooked it up. It worked just as well or better as a
charger. The only difference was that the scrap electrode semed
to be dissolving, and the black soot seemed thicker. Probably
the half wave pulsing.
I decided to make another one with a full wave DC using 4 diodes
in a bridge arrangement. I didn't have a lamp socket, so it was
hooked up without one and tried out on an old hub. Within a minute
the diodes were hot, so I put them in a cup of clean water. [rubber
gloves time] Soon the rust was foaming up like bubble bath. After
a few minutes the water was about to boil, the cup was warm, and
the wiring hot! The voltmeter said 98V DC!!
So I ended the test. Impractical, but in less than 5 minutes the
part was cleaned of rust!
When a lamp was added it worked very well, limiting itself. It
also seems to de-sulphate batteries better. I'm still hestitant
to try it on good batteries until more testing is done.
Here it is. A piece of varnished wood, a socket and
bulb from a chandelier, four diodes, some wire, and the bottom
of a plastic bottle held with a screw. Somehow the bulb governs
the power coming out to only what is neccessary. A bigger bulb
allows more voltage, which seems backward to me. In one case a
40W gave 7V, a 60W gave 12v, and 100W gave 40V. Unplug the
cord every time you want to touch the parts!
Another site suggested a capacitor would also work, or a dimmer
switch, but it wasn't tried.
UPDATE: A capacitor type was made and tried
a year later, and it works much faster. [in the time it took to
write this it had derusted a small part, and the water was almost
boiling.]
It is just a big capacitor/condensor and a bridge diode,
which is four diodes arranged with diamond like connections. Two
from AC and the cap, two to DC out.The bigger the uF the more
juice it zaps in. They say any uF will work from 1uF to over a
100. When plugged in it lets off a zaapp. Be careful with this
one.
The diodes are on a cooling grid from a computer, because they get quite hot.
So back to derusting. Several others
additives beside washing soda have been suggested, such as baking
soda or lye, but washing soda is not harmful and can be added
to the wash as well. And it works. The treatment removes rust
without attacking metal or machined surfaces. When a hub was put
in with greasy bearings, they came out unharmed with grease untouched.
Try that with sandblasting. In fact a few times I have put in
parts that looked totally rusty, and yet there were coatings underneath.
A Craftsman rachet found at wreckers must have been buried for
a few years. It was rusted up solid and was taken for testing.
After several hours the outer rust was gone, and about half of
it had a chrome coating. Later that day the rachet was free to
move and it was taken apart, 'boiled' again, then greased, and
works great.
Other parts were put in totally rusty yet when removed
they were partially covered with paint. The overlying rust was
removed without harming the paint beneath it. Like it was washed
off.
How poetic.
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Update: Another web method for removing rust
is soaking in molasses. Easy to try. Just molasses and water.
Website ratios varied from 5 to 1 up to 12 to 1. So it doesn't
need to be perfect.
A small carton was mixed with a jug of water and a
piece of rusty fender was sunk half way in. It was placed in a
corner of the basement and after about a week a foam appeared,
soon followed by a smell that resembled sewer gas.
Some say this effect works because of Chelation. By the smell I would say some kind of Fermentation. They say the part shouldn't be lifted out at all, so it stayed there for almost three weeks. By that time the smell meant an end to the experiment.
Waddaya know? It worked.
The part was shiny metal when removed
but soon developed a surface rust.
So, if you aren't in any hurry and can place the container
outside so the smell doesn't gag you, then molasses rust removal
is a cheap and low effort way to clean metal.
Update: I've tried this on small parts and it is slow and the parts seem to re-rust quite fast.
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Another way to deal with rust is Sandblasting. For years I had the bucket-o-sand and a gun set-up.
This summer I was driving past a yard sale
and stopped. The guy had a new in the box bottle type blaster
for $75. I checked the catalogs at home and saw it was half price,
then forgot about it. The next day it was still there and he took
$30.
I welded on two wheels and a cross handle to wheel it around instead
of carrying it. All it needs now is a proper deadmans gun.
It blasts much faster than the bucket-o-sand, and uses up sand
in no time. All my protection had to be upgraded as well. Sand
flies everywhere with force. Breathing mask, ski goggles, and
a cheapo leather hood.
.