Magnesium = great choice: easy to saw in half giving you two bricks,
easy to resurface witha coping saw or hacksaw, and good, not
excellent refraction..no oxygen absorption though like you'd get with
charcoal. Siliquar, equally good..if doing production work
impressionite boards..charcoal still reigns top in my silver work
'book", but the reversible grey/white dual temp disposable boards are
acceptable though need frequent cleaning, if frequently used with
pastes instead of the "self pickling" fluxes like batterns,Prips,etc.
Platinum boards last long for silver, but price wise why?
Rio highest cost, Contenti,Rosenthal,Baldwin-Taylor hardware,FDJ are
all cheaper..for the same products..Dick Blick occassionally has the
honeycomb boards on sale..the ONLY benefit to them is easy pin
driving ,or positioning..I always have to put another type under
them, and they break readily as the holes are like perforations..so
they are my least recommended choice..
If you must experiment with the honeycomb boards and are working in
silver,filling your annealing pan with garden grade activated
crushed charcooal works quite well..in fact, i keep a copper pan on a
swivel base ( lazy susan) filled with charcoal from the garden dept.
at any home store around to use as is.it supports work,absorbs
oxides, can be piled up as needed to create good all around soldering
environment and is cheaper than blocks..and last at least as long..I
got a case of 3 lb. bags ( 12 bags per case ) on sale at Lowe's for
1.00 a bag..so at the end of gardening season check your home supply
stores for their closeouts..It has happened two years in a row now,
and i have a nice stash of about 22 bags after two years of use
daily.(.or most days.)