Martin Howard on mon 27 sep 99
For many of us a white tin glaze is important. We use it as a base for
decoration.
But tin oxide is expensive and the alternatives do not have the soft
white quality of tin oxide glaze.
Tinfoil is a common throwaway waste. We used to save it for several
groups who could recycle it, but they have stopped for some reason. So,
we now have several bags of tinfoil awaiting some use and recycling
destination.
Could there be sufficient metallic oxides, possibly even some tin,
within that lot of waste?
If so, could it prepared by just putting it in a container in the kiln
and heating to 1140C?
Does anyone know the composition of these tinfoil containers?
I wonder if yet another waste product can be of use to potters around
the world?
Martin Howard
Webbs Cottage Pottery and Press
Woolpits Road, Great Saling
BRAINTREE
Essex CM7 5DZ
01371 850 423
araneajo@gn.apc.org
John Rodgers on tue 28 sep 99
Martin, in my experience, what we always called "tinfoil" was in fact,
aluminum foil....very thing aluminum foil that could be peeled off of gum
wrappers, cigarette packs, etc, and saveed. Usually rolled up in a ball.
Sometimes we could make quite a large ball of "tinfoil"!
I don't think you will actually find any tin in what I know as "tinfoil"!
John Rodgers
In New Mexico, USA
Martin Howard wrote:
> ----------------------------Original message----------------------------
> For many of us a white tin glaze is important. We use it as a base for
> decoration.
> But tin oxide is expensive and the alternatives do not have the soft
> white quality of tin oxide glaze.
>
> Tinfoil is a common throwaway waste. We used to save it for several
> groups who could recycle it, but they have stopped for some reason. So,
> we now have several bags of tinfoil awaiting some use and recycling
> destination.
>
> Could there be sufficient metallic oxides, possibly even some tin,
> within that lot of waste?
>
> If so, could it prepared by just putting it in a container in the kiln
> and heating to 1140C?
>
> Does anyone know the composition of these tinfoil containers?
>
> I wonder if yet another waste product can be of use to potters around
> the world?
>
> Martin Howard
> Webbs Cottage Pottery and Press
> Woolpits Road, Great Saling
> BRAINTREE
> Essex CM7 5DZ
> 01371 850 423
> araneajo@gn.apc.org
Gavin Stairs on tue 28 sep 99
At 02:33 PM 9/27/99 -0400, Martin Howard wrote:
>----------------------------Original message----------------------------
>For many of us a white tin glaze is important. We use it as a base for
>decoration.
>But tin oxide is expensive and the alternatives do not have the soft
>white quality of tin oxide glaze.
>
>Tinfoil is a common throwaway waste. We used to save it for several
>groups who could recycle it, but they have stopped for some reason. So,
>we now have several bags of tinfoil awaiting some use and recycling
>destination.
Dear Martin,
Where on earth do you get tinfoil? I know we call the silvery foil that
commonly wraps our perishable goods tinfoil, but I would guess it is almost
invariably aluminum, these days. The last holdout that I know of was tin
tubes for things like tooth paste and oil paints. Most of them are plastic
now. I don't even know if you can buy tin tubes any more. You used to be
able to get them for making your own compounds and paints. Perhaps
pharmacists will have some wastage of these, I don't know.
If you could find tin, I doubt it would be pure. Probably quite a bit of
lead in it, the old stuff, anyway. If you find any modern tin being used
in packaging, it probably has little lead, but undoubted some other stuff.
Most non-foil tin products are now may of "white metal", which is not a
definite alloy, but any one of many tin-zinc-copper-what-have-you alloys
used in the dies casting industries. And if you use if for food surfaces,
be sure to test for lead and cadmium.
Calcining low temperature metals is a bit tricky. Many sublime and
evaporate, so you get fumes. And you probably have to melt most of them,
and then the oxidation surface is reduced, which makes it slower. Just as
well, because burning metals is very exothermic, which means you may end up
melting more than the metal. A mixture of aluminum and iron powder, iron
oxide is called thermit, and it produces molten iron. Very nice for
welding railway rails, but not nice for your kiln. Not to say you can't do
it. Just be careful about loading up the kiln with stuff that might end up
on the floor. That's what crucibles were invented for.
We used to get tinsel to throw onto our Christmas trees, too. It was
supposed to be tin, by the name, but I expect it was lead-tin. Solder. It
draped much more nicely than the replacement aluminum, and now aluminized
mylar. Tin and lead foils are very soft, and bend easily. The aluminum
foil is much stiffer, and less friendly. Lead used to be used for lots of
things, because it was so nice to form and had such a nice heft to it.
Never more. Now even pewter has no lead in it, and doesn't act like pewter
at all. A pewter mug had dings in it, and dulled with age. They were
never quite round. And a pewter box with a hinge never quite shut square.
Now a pewter mug is shiney and round, and looks the same as the day you got
it a decade after, and a pewter box shuts tight, period.
I am getting old.
Gavin
Debby Grant on wed 29 sep 99
I just have to add my 2 cents to this thread. You are all right - the
substance we got used to calling tin foil is really aluminum foil today.
But back in my youth during "the big one" WW2, we used to save
the inner wrappings of sticks of gum and candy and make balls of
them and then turn them in for the war effort. We all thought we
were saving tin foil and probably we were. There's no tin in tin cans
either but once upon a time there probably was.
Debby Grant in NH
Janet Kaiser on wed 29 sep 99
"Tin foil" is not only made of aluminium, it is also sometimes made of
plastic and has no metal in it at all these days! It may look shiny and
silvery, but would just burn off. (Checking the package sometimes gives a
clue but not always).
In the UK, save it and take it to OXFAM. They still collect aluminium for
recycling and raising money for overseas aid. Take all your beer, beverage
and other cans with pull tabs along too! Check with a magnet that it is
aluminium and not tin first.
John Rodgers wrote:
>Martin, in my experience, what we always called "tinfoil" was in fact,
>aluminum foil....very thing aluminum foil that could be peeled off of gum
>wrappers, cigarette packs, etc, and saveed. Usually rolled up in a ball.
>Sometimes we could make quite a large ball of "tinfoil"!
>
>I don't think you will actually find any tin in what I know as "tinfoil"!
>>Martin Howard wrote:
>> For many of us a white tin glaze is important. We use it as a base for
>> decoration.
>> But tin oxide is expensive and the alternatives do not have the soft
>> white quality of tin oxide glaze.
>>
>> Tinfoil is a common throwaway waste. We used to save it for several
>> groups who could recycle it, but they have stopped for some reason. So,
>> we now have several bags of tinfoil awaiting some use and recycling
>> destination.
>>
>> Could there be sufficient metallic oxides, possibly even some tin,
>> within that lot of waste?
>>
>> If so, could it prepared by just putting it in a container in the kiln
>> and heating to 1140C?
>>
>> Does anyone know the composition of these tinfoil containers?
>>
>> I wonder if yet another waste product can be of use to potters around
>> the world?
>>
>> Martin Howard
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