I have a large oak stump in my shop. It was a living tree not two
years ago. It sat outside on its side for a little over a year
before I worked up the courage to roll it (using my car, a logging
chain, a johnson bar, etc.) to my shop 40 yards away and partly
uphill over rough terrain.
It now sits proudly in the center of my shop with a vise and various
other tools attached.
One of the things is a large cake of lead.
I’m now unbolting and removing everything from the top of it so I
can cover it with cowhide and when I lifted the cake of lead I
noticed a fine coating of white powder caked under my cake.
I’m wondering if any of you folks know what it might be. I’m
guessing lead oxide but that implies oxygen and one assumes more
oxygen would brush up against the exposed surfaces rather than the
underneath. And will cowhide make it stop forming?
Without seeing it myself, if the white substance seems a bit stuck
to the stumps surface, it might be mycelium, or fungal root systems.
I grow mushrooms as a hobby, and there are several types that grow in
the wild and prefer oak. Who knows, you could be eating shiitake in
the future!
I suspect it’s just mold. A large stump takes much longer than 2
years to dry, especially when left outdoors. The water leaves via the
endgrain of a cut log, where the tree’s plumbing was severed. That
cake of lead prevents the water from evaporating in that area, so it
stays damp and grows mold. White mold is a common sight on drying
logs. I’m drying some oak burl now, and it has some white mold. You
might also find white mold growing on the bottom where it’s against
the floor. Indoors, the stump will eventually dry. So long as you’re
not stirring up mold-laden sawdust, it probably isn’t harmful, but
someone with more knowledge about the health concerns of wood molds
would have to comment on that matter.
Don’t worry too much. It is not anthrax. Even dry wood has some
moisture content. Moisture accelerated the oxidation of the lead.
What you have is lead oxide. Queen Elizabeth I used if for makeup,
it used to be the major pigment in lead based paint. It is somewhat
toxic. Long term exposure is the most common health risk, so just be
careful and clean it up without breathing it or getting it on your
skin.
Please don’t carry on about how bad ‘Lead’ is, you have substances in
most studios that are more toxic, And Metallic lead as he is using is
relatively inert.
Don’t mix up the myth of lead with the facts about lead as a metal
and lead as its various compounds… Sort of like the ‘cyanide’
discussions we had
I don’t “play” with it. I’m a jeweler and I work with it. I also work
with really hot things and electricity and sharp things and hammers,
even cyanide.
That white powder is “white lead,” once used as a white pigment for
house paint. It is lead carbonate, a weathering product produced
when metallic lead comes into contact with moisture and air.
The white stuff may be mold, mildew or fungus. I had a large sycamore
stump for a while and, even with a dehumidifier running in the room,
things would start to grow if I left it standing on the flat end
during the first couple of years. I got it as a freshly cut chunk of
a trunk. After about 3 years I stopped using the dehumidifier and
felt comfortable leaving steel anvils in it for a few days at a
stretch.
Please don't carry on about how bad 'Lead' is, you have substances
in most studios that are more toxic, And Metallic lead as he is
using is relatively inert. Don't mix up the myth of lead with the
facts about lead as a metal and lead as its various compounds...
Sort of like the 'cyanide' discussions we had
Is this correct? I have seen some cool little (brass?) patterns that
the Afghani Silversmiths use to form silver by pounding on it with a
lead “ram” or punch. (Thanks to Sam Patania for allowing me to visit
his studio!)
They evidently use lead to pound on the silver sheet and conform it
to the pattern of the mold or whatever you want to call it. Some have
quite a bit of detail that it would be hard to get using other
methods.
It seems like a handy technique but I wondered about the safety
issues of using lead. What do people know about this that isn’t just
hearsay? (I assume Kay knows something due to her comment.)
Please not I did not say it was harmless, little we use is harmless,
Just that it is safe to use if correct techniques are used.
Most of what people think of as lead is lead dust either from
tetraethyl lead that used to be used in gasoline or lead pigments
which children would ingest.
The reason why Lead is banned in jewelry manufacture is because it
was used in cheap children’s trinkets and they would suck and or
swallow them allowing the lead to react with the hydrochloric acid in
their stomach, resulting in very toxic levels.
Hell for years Lead was (and in some areas still is) used as weights
for balancing the wheels on your car.
Using it has a hammering block is quite safe, as long as you don’t
take it home every night to fondle or grind up and use as a
condiment.
but I wondered about the safety issues of using lead. What do
people know about this that isn't just hearsay?
I have an old, old bottle with a bottomfull of mercury in it that I
acquired years ago. No use for it, I just collect things and it’s a
great old bottle, too. Plus it’s a hassle to dispose of. So we had a
young man working here who is scientifically illiterate. I showed it
to him along with the other contents of the chemical cabinet and his
face went white. A couple of days later I went in there and the
mercury was wrapped and taped in plastic… Like it was going to
jump out of the bottle and get him. I also have a lead block sitting
on the bench next to my workbench, ready for anything.
There are no safety issues of using lead or even mercury, in a
manner of speaking. The safety issues are about INGESTING them.
Otherwise it’s just a bottle on a shelf and a block on the bench.
That’s not to downplay the danger if you do get it in your system.
If you do the die striking John mentions and handle lead a lot,
don’t wash your hands and then lick your fingers or eat an apple,
then you likely will get some into your system, and it accumulates.
I work in my shop with the rules I was taught in chemisty lab -
don’t put your fingers in your mouth or touch your eyes. It’s just
second nature, now.
Lead must be in a form that your body will absorb, and you need to
get it into your system somehow for it to be toxic. If you ate or
inhaled the white powder on the stump (which looks, walks and sounds
like a duck - lead oxide or carbonate), then you’d have a problem.
Handled properly it’s just not that big of a hazard. Wash your hands
With mercury it is not necessary to ingest it. It can be inhaled and
absorbed through the skin and mucous membranes. It will lead to
complications and potential death in all of these forms.
Whatever that stuff was, I didn’t taste or snot it, so it’s good. I
removed all my anvils and my vise from the stump.
I painted it with shellac, then two coats of polyurethane, and after
that dried placed a sheet of contact paper over the top and covered
the whole thing with a nice piece of leather. I bolted and screwed
all the tools back on, and placed the lead there too (after cleaning
off the white lead stuff).
I have seen some cool little (brass?) patterns that the Afghani
Silversmiths use to form silver by pounding on it with a lead "ram"
or punch.
hi there John— i occasionally work in west India along the
Pakistani border; there we call those dies (you used the word
‘‘mold’’) [thampas, thappa, or ta’wiz]… yes a chunk of lead is used
to depress the annealed sheet of silver into the die but a piece of
thin cardboard is used between the two elements so that contamination
does not occur… the sheet of thin cardboard is like a western index
card… occasionally the cardboard gets perforated in which case hard
and vigorous brass brushing is called for to remove to offending
lead… one must remove it all otherwise it will eat away at the
silver sheet when it is heated to soldering temperature… a lead
block ( like a stel bench block) is not an uncommon item in a western
jewelers studio either… several common supply shops carry it… i
prefer the thinner sheet of around 2mm thick which can be found in a
large hardware store in the roofing supplies department… for
further and far more erudite discussion on the subject i would refer
you to page 102 of Oppi Untracht’s book ‘Traditional Jewelery of
India’… He was a great man…
That’s one cool set-up! Ooh to have half of that equipment. Maybe in
a few decades I’ll have accrued that amount of tools. It’s great to
see other folks’ workshops - thanks for the pics.