If a latecomer (well qualified, however – I lived on a sailboat for
nine years) to this thread can offer a couple of observations about
keeping tools (and steel parts) rust-free, here they are:
IMHO, good old WD40 is hard to beat. This was my experience on the
boat, and was also the conclusion reached a few years ago by “Practical
Sailor”, when that consumer publication tested corrosion preventatives.
Actually, a wax-based product called Boeshield came in first, by a hair,
but WD40 is lots cheaper and easier to find away from boating specialty
shops, and was only behind Boeshield in the salt water spray test anyway.
Last time I looked, there wasn’t too much salt spray in my shop…
As long as I was religious about drying tools, then either misting them
with WD40, or wiping with a previously-sprayed rag, I never had a problem
with rusting, despite nine humid, subtropical mid-atlantic summers and
condensation during the winter. In my jewelry shop, I use the same
procedure on any bare steel or polished surfaces, like rolling mill
rollers, dies, hammer heads, etc. So far, no problems.
A couple of posts suggested using silica gel as a drying medium; this is
common among boaters, too, and works as long as you understand that the
gel gets saturated and needs to be dried in the oven every once in a
while. It doesn’t do much good unless in a small confined area like a
tool drawer that isn’t opened constantly, or a closed box; otherwise it
saturates too fast.
I can’t really recommend the other type of chemical dehumdifier that
boaters also use, which is basically a vented can partly filled with
calcium chloride. “Dri-Z-Air” is one common brand. CaCl is
hygroscopic, and will constantly suck moisture out of the air. It works
so well that the can fills up, continues condensing moisture, and you wind
up with saturated CaCl solution dripping everywhere! Unless you are
vigilant about emptying the excess condensate, you soon have a mess.
About a month ago, a roof leak targeted my stationary tools bench,
squarely over the Unimat lathe. Although I was out of town for the
weekend, when I got back there were a lot of water stains on the bench and
floor, and some dried plaster dust on the lathe, but no rust. I attribute
that to the squirt of WD40 it gets after every use. The WD40 can has its
own spot on the bench next to the expensive tools.