La pedra en sec. Materials, eines i tècniques tradicionals a les illes ...

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* * *: 5 5.1 THE WORK
Description
The clearing of stones from fields
used for farming was one of the sources
of stones for dry stone masonry,
but it was often unable to provide the
material required for large projects.
For this reason, large blocks of stone
were often broken up and the fiters
(rocky outcrops) removed, or small
quarries would even be dug near the
building site and in exceptional cases
some distance away.
Two methods were used to quarry the
stone in the past - lime bore holes or
wedges -which were slow but did
enable stone in good condition to be
obtained. The former consisted of
making a hole in the rock with a gimlet
ideally following pre-existing small
cracks. As the hole was made the
powder was removed with a small
wooden or metal spoon.
Once the hole had been made, lumpy
and densely packed quicklime was
put into it, it was watered and closed
with red earth or with wood, preferably
poplar. The expansive force of
the quicklime split the stone which
was finally broken up into large and
small crowbars.
The second technique consisted of
placing a series of wedges in the
holes made with the gimlet. They
were then rhythmically hit with an old
large hammer to break up the rock
with a degree of precision.
Gunpowder has also been commonly
used over the years, especially in
large terraced fields and roads. Dynamite
has always been seen as not very
suitable as it causes the stone to split
when it is worked and produces
cracks which damage it in the short or
medium term.
Tools required
Gimlet, small spoon, crowbar, lever,
wedges (wedges and flats), large
hammer.