Ribbon Grade -
Ribbon slate is characterized by an
ornamental dark band which, in the case of copings, usually runs
parallel with the length of the coping. A ribbon may be wide, narrow
or even double. In a wide coping, there may possibly be more than
one ribbon. Note: Although Ribbon grade is not recommended
for exterior use, with proper pitch and the ability to dry, a ribbon
coping may be serviceable for over twenty-five years or more. Ribbon
slate is supplied in Machine Gauged, Sand Rubbed or Honed finishes.
- Natural Cleft Finish is a rough
textured, split face finish. The bottom is gauged to an even plane
and the thickness, although varying due to the facial deviation
of the cleft, is constant within the maximum thickness specified.
(NOTE: The facial deviation in Natural cleft finish may appear
more pronounced with regard to the edge plane in a long coping run.)
Machine Gauged Finish is a smooth, even finish which approaches
the honed finish. However, slight swirl marks are usually visible.
Sand Rubbed Finish is a smooth, even finish with a slight
stipple equal to about 80 grit sand paper. Honed Finish is
a smooth, satin finish equal to about 240 grit.
- Hone & Arris Edge is a honed exposed edge and either
a 1/8" chamfer or a 1/8" radius on the top exposed edge
to remove the sharpness. This may be specified in conjunction with
any of the facial finishes, however in the case of Natural Cleft
finish, the 1/8" radius is normally used rather than the chamfer.
Arris Edge is the 1/8" chamfer or 1/8" arris on
the top exposed edge without honing the edge. Sawn Edges
are edges directly from the saw, which are usually very smooth and
sharp as they are cut with a diamond saw. Other Edge Profiles
are subject to availability of tooling and should be investigated
prior to specifying.
Coping and caps are supplied in 3/4", 1", 1 1/4",
1 1/2" & 2" Thicknesses. Other thicknesses are available
to comply with special field requirements.
Sealers usually darken the slate and give a glossy appearance.
Natural cleft finish and Sand Rubbed finish may be sealed suitably,
however, sealers may not adhere nor give a desirable appearance
to Machine gauged or Honed finish. Impregnators usually do
not as radically alter the color of the slate and give a more satin
finish. As with the case of sealers, impregnators may not be suitably
used on machine gauged or honed finish. Oiled Finish is usually
a treatment reserved for interior applications. Oil darkens the
slate without producing a sheen.