Standard stretcher bars are also
known as an SSB, and the gallery
stretcher bars commonly known as a
GSB. Made from kiln dried Fir wood,
carefully selected to avoid dampness
and
warping, and profiled to give
maximum strength and stability to
the frame when joined together.
Unlike pine woods fir does not
continue to grow and warp when it
has been heat treated, nor does
it express damaging timber oils
normally seen on some pine
products.
The profiles
on the stretcher bars are slightly
rounded. This has two advantages:
1) It allows the framer to see and
obtain clear edges on images that
have precise borders, and
2) It also allows the canvas weave
to "roll over" the profile rather
than snap over a sharp edge which is
a major cause of canvas cracking.
Bars are available in
three profile sizes:-
1) SSB or Standard Stretcher Bars
are 40mm wide and 18mm deep. The
unique profile design and 40mm width
gives extra strength over longer
lengths. This helps prevent
"bowing" when stretching the canvas.
2) GSB or Gallery Stretcher Bars
are a chunky 35mm wide and 38mm
deep. Its sheer strength is obtained
from the profile design.