I beg to differ, but crushed limestone is not lime.  The burning of
limestone (or oyster shells as was recently demonstrated for us in
Williamsburg at the APT conference) causes a chemical reaction that drives
carbon dioxide and H2O out of the limestone to make it lime.  And slaking
lime is not adding water to hydrated lime to make lime putty.  Slaking
requires "quicklime" which reverses the some of the chemical process and
adds H2O back into the lime; and as the lime mortar is exposed to the air
over the years it carbonates with CO2.  the brickmaker at Willimasburg said
that slaking lime generates as much heat as it takes to burn the lime inthe
first place  (laws of thermodynamics= You can't win, You can't lose, and You
can't break even)
-----Original Message-----
From: Henry Roeters <[log in to unmask]>
To: [log in to unmask]
<[log in to unmask]>
Date: Sunday, November 22, 1998 8:37 PM
Subject: Re: masonry cement


>????
>Lime is a product of limestone.  You crush limestone into a powder.....you
get
>lime.
>Pretty much the same stuff that farmers use on their fields, but further
>refined.
>Masons lime is now autoclaved to remove impurities, and add air-entraining
>properties.  It used to be that the lime would have to be "slaked" by
putting
>a bunch on a mudboard in a mound, making a hole in the middle (like a
>volcano), and pouring water into the hole.  Slowly, the lime absorbs the
>water, and takes on a cheesy consistency.  You cut the mound into quarters,
>mix a little bit, and do it again.  This process took three days.  You
would
>then add this to your mortar, plaster, stucco, or what have you.  The
reaction
>of the lime with the other constituents creates heat, and acts as a
catylist
>in curing, rather like "Bondo".
>The nice thing about lime is you can control the amount of cure involved
with
>what you are doing.  If you are laying stone, you want a very "weak" mix,
to
>allow for the expansion and contraction of the stones.  There are many
>different recipes for all the "muds", and all have their place in the grand
>scheme of things.
>Lime is our friend!
>Henry Roeters