Stephen Rosenthal wrote:
"I’ve had a set of LN chisels housed in their leather tool roll for at least 25
years. They are not my everyday chisels. Not a speck of rust. Even more
remarkable (if leather is going to be accused of contributing to rust) is my
dad’s WW II military issued knife, complete with belt-looped leather sheath.
This 80+ year old treasure has been removed from its sheath no more than 10
times in the last 60 years. Again, not a speck of rust. I assume the LN tool
roll is veggie tanned leather, but I have no idea what type the knife sheath is.

"Since we both live in the SF Bay Area with similar climate conditions, I wonder
if something else may have contributed to your rust issues."



Certainly there other causes of rust in my house. I live directly over the
original course of one of Berkeley's culverted creeks; although the culvert (the
storm drain) now runs under the street next to my house, the land still goes
steeply uphill from me in three directions. For decades the house was shaded by
a large volunteer live oak that grew two feet from it and spread its canopy over
almost half the roof (This could be seen in Google's satellite photos). We only
got French drains a couple of years ago. The house is just slightly damp---
nothing serious, but slightly. The problem was worse during several decades when
there was effectively no heat in the house, and the humidity and heat cycled
grossly every day during winter. I have other dampness issues, for instance
persistent slight mildew on certain bookbindings--- again, not much and not
everything, but undeniably there. Contact with leather won't cause rust in
conditions of complete absence of moisture (or air); it just speeds things up
when moisture is there.


I have never had rust on every tool, or on much of any tool. And some of my
leather sheaths (or on-the-bench edge protectors) have not yet developed rust,
despite 30-plus years of use. But the first time you find rust (or mildew) it is
like the first time you find a flea in your bed: you feel vile, degraded,
ashamed. You wonder what you have done wrong, after so many years of noble
freedom from  filth. And you try to figure out what caused it. For my rust
issues, I saw that it occurred disproportionately on the the tools with leather
sheaths I made for them back in the 1980s. After the rust was removed from the
knifes it soon recurred in exactly the same spots and even shapes, and then I
dissected the sheaths and found deep rust stains and surface rust on the insides
of the sheaths. There was no way to remove it so I got rid of the sheaths, even
though I had made them properly with freehand awl-and-harness-needle saddle
stitch and was proud of them. I suspect that the difference between the sheaths
that developed rust and those that didn't was that I must have used the rusty
ones on damp days, so that removal of the knife and replacement in the sheath
pumped damp air into the sheath--- but that is just an onagered (wild-assed)
guess.


I was bolstered in my distrust of leather for storage when I learned that at
least some collectors of historic firearms don't keep their treasures in their
holsters, especially if the holsters are historic too, and old enough to have
accumulated acids from degradation or air pollution. Leather does absorb
corrosive air pollution, which is one of the main causes of decay of leather
bookbindings, as I know in far too much detail from professional knowledge of
book conservation. If anything I trust vegetable-tanned leather less than
chrome-tanned, since in book uses the veg-tanned leather is far more susceptible
to "red rot" and other decay, especially from air polluted sulfur oxides, which
are catalyzed into sulfuric acid in the leather


Rust behaves erratically and unpredictably, almost as if it were consciously
malicious. I once gave a demonstration of tool repair and rust removal for a
national hand bookbinding group, and I needed rusty spokeshaves and spring
dividers to demonstrate on (four repetitions so that all attendees could get a
close-up view). I couldn't find any rusty ones in several visits to the Alameda
Flea, so I decided to deliberately cause rust on some poor tools ones that I had
anyway. I couldn't get it to happen. I wet the spokeshaves and left them
overnight; then wet them and left them outside several days; then wet them and
left them half buried in the yard, and cover the bits that stuck out with dead
leaves. No rust. I had a year lead time, so there was plenty of opportunity to
experiment.  Eventually I managed to get a bit of rust on a few tools, enough to
serve as examples, and did my talk successfully. After that I started finding
rusty spokeshaves and spring dividers again.

Rust never sleeps, they say; but it sure naps at times, then wakes up again when
you least want it to. I prefer to act pessimistically, and don't use any leather
for tool storage.
Tom Conroy
Berkeley