Soldering hearths

G’day. I doubt whether many ordinary brickyards would have the
kind of soft insulating bricks which will hold pins. For that type
you need a brick maker that specializes in furnace insulating
bricks. These are placed behind the high temperature inner furnace
bricks. They are much lighter, being very porous and they are
softer - can be scraped clean… I am very lucky being in New
Zealand, where there has been much volcanic activity in the past and
in fact there still are several active volcanos. One of these
volcanoes chuffed out what geologists call acidic larva, which is
mainly silica pumice, and, which, when it left the volcano was a
very nasty red hot cloud called a ‘neu=E8 ardente’ We can still find
decent sized lumps of it on a few sea shores, where it washes up
because it floats on water, which is what I use very satisfactorily.
You can use barbecue charcoal, but it is very messy and friable, and
is difficult to find a bit with a flat enough surface. Some shops,
especially pharmacies sell pieces of pumice used when showering or
bathing to rub away calluses on hands and feet.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ