"Paul" wrote in message
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"Ed Huntress" wrote in message
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"Paul" wrote in message
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"Ed Huntress" wrote in message
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"Paul" wrote in message
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"Ed Huntress" wrote in message
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"RoyJ" wrote in message
m...
I ran my trusty Kohler 301 12 hp a bit low on oil, trashed the con
rod. (My bad)It looks like the crank is ok but it has a decent
buildup of galled aluminum on the one side. I could scrape it off but
that would risk scratching the journal. Any bright ideas how to get
the aluminum off without touching the journal? Maybe a few drops of
a strong alkaline like lye???

Lye is good, but not a few drops. You'll need to cover it with
solution.

If your patience is slim and if you want to do it at room temperature
(a safe idea), you can use some Pequa drain cleaner. That's a
straight 45% lye solution in water, and it's so concentrated that
it's actually slightly viscous. 45% is dangerous to handle but it
does the job. Dilute 50% with water if you're edgy about using a
concentrated solution.

I've used 20% with success -- in fact, I've wrecked a few aluminum
parts with it, trying to frost them. d8-) For reference, a 40%
solution is 1 kg of lye to 1.5 liters (1.5 kg) of water. That 1 to
1-1/2 ratio is easy to remember.

My lye tank for small parts is a plastic Tide bottle cut in half.
Don't use it with hot lye.

--
Ed Huntress


CLR (calcium, lime, rust remover) works too.
Paul

It contains some mild organic acids. They probably will have no harmful
effect over a short time, but I wonder how long you can leave a steel
crankshaft in them. Any idea?

--
Ed Huntress


Ed,
I've soaked HSS taps in CLR for upto a week to remove aluminum stuck in
the teeth. The surface of the steel turns black but the cutting edges
are still sharp.
Paul

Hmm. That black oxide may be a problem on a crankshaft. At the very least
it would have to be removed.

Have you ever tried using a lye solution? It eats aluminum pretty fast
and it doesn't hurt the steel.

Warm, 40% lye solution will actually bubble hydrogen gas off fairly
violently as it eats the aluminum. But you don't need a 40% solution to
do the job on cutting tools. A couple of tablespoons of lye in a cup of
room-temp water will do it.

--
Ed Huntress

I have not tried using lye. When I first did some online research about
removing aluminum a few years ago I found recommendations for both lye and
CLR. I already had some CLR so I gave it a shot and it worked, so that's
what I've been using. Also, the CLR appears to less hazardous, at least
according to the MSDS.
The black oxide may be problem on a crank shaft, but taps I use the CLR on
(normally 3/8 & 1/2 NPT 8" lg. pulley taps) actually get aluminum stuck in
the teeth less often after they have been in the CLR.
Paul

Ok, I could see that. The black form of oxide sometimes has a pretty weak
grip on steel (the electrical de-rusting method produces some black smut
like that, for example), so maybe it's forming a barrier.

Interesting. Since I have 85-year-old plumbing in my house, I'm very
comfortable working with lye. g It can be a little tricky in higher
concentrations. But the small quantities and low concentrations needed for
frosting aluminum, or for dissolving it in moderate quantitites, aren't much
of a problem. You can flush it down the drain. I do it weekly, as a matter
of fact.

--
Ed Huntress