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APPLICATION SPECIFICATION
CG 5.1
June 1, 1996
GACOFLEX U-66
URETHANE RUBBER COATING SYSTEM FOR ROLLER APPLICATION ON PLYWOOD DECKS
Plywood shall be selected and installed in
accordance with specification CG 3.0. Plywood shall be AC Exterior
Underlayment with plugged cross bands under the face meeting specifications
of the American Plywood Association. All interior grades, including those
with exterior glue, are not acceptable. Plywood marked "Exposure
1" is not acceptable.
2. PREPARATION
The deck area must be clean and dry. New
plywood does not require primer. Prime galvanized metal flashings with a
light coat of Gacoflex E-5320 two component water based epoxy. If U-66 is
to be carried onto masonry, concrete or painted surfaces, also prime with
E-5320. E-5320 is mixed in equal parts to which 10 or 15% water should be
added. It must be well mixed. Apply by brush or roller at the rate of one
gallon per 300 square feet and allow at least an hour for drying before
coating with U-66 series urethane. Do not apply E-5320 primer when
temperature is below 40 degrees F. Use masking tape on vertical walls to
terminate coating in a clean, sharp line. Note: Only the final coat of
urethane is carried onto the masking tape. Tape must be removed while the
coating is still wet.
3. MIXING
Gacoflex U-66 urethanes are two component,
1:1 ratio elastomers. Part A is pigmented and should be stirred prior to
mixing with an equal volume of Part B. Best results are obtained by
pouring a measured amount of Part B into a plastic container and mixing in
an equal amount of Part A. This mixture must be stirred thoroughly with an
electric drill and stirring paddle. Scrape sides of container often while
mixing to insure there are no portions left unmixed. Small mixtures (under
two gallons) can be mixed by hand, but must be well mixed. The pot life is
about 1 hour. Do not use U-66 when ambient temperature is above 80 or
below 40 degrees F.. If graininess is observed in either Part A or Part B,
materials should be warmed prior to mixing as per label instructions, U-66
Part A.
4. SPACKLING AND TAPING
It is helpful to prepare the plywood joints
by sanding with a 9 inch rotary sander-grinder with a 24 grit sanding
disc. This will level minor changes between sheets and remove slivers and
burrs. Do not over-grind cutting ruts or troughs in the plywood. Apply a
light coat of spackle to all joints, metal edges, and rough spots. Use a
spackle or putty knife. Make spackle by adding a small amount of Patch-All
powder to already-mixed U-66 (about 1/2 pint powder by volume to 1 pint of
U-66 will be enough for about 100 SF of deck area). Spackle should be
similar to a runny cake batter and runny enough to "wet" the
plywood. Let this spackle set for about 1/4 hour but not more than 1 1/2
hours. Apply Gacoflex 66B tape to all joints, cracks and changes of plane.
Premix a small amount of U-66 urethane as noted above. Thinning this
mixture about 5 to 10% with T-5116 Thinner will make taping easier. By
brush or roller, apply a five to nine inch wide stripe along all joints to
be taped. While this is still tacky, unroll the tape into the coating and
apply a heavy coat of liquid material over the tape, smoothing out
wrinkles or fish-mouths. Stretching the tape very slightly while
installing will help it lay flat.
5. BASE COAT
Base cast can be installed after coated
tape has set about 1/2 hour. Apply by roller an overall coat of U-66
urethane, using one gallon per 100 square feet. Be careful not to move the
tape when rolling over it. Allow to dry 36 to 48 hours until hard.
6. SECOND COAT AND TEXTURE
Before applying second coat, it is helpful
to lightly sand the surface to feather edges of tape and smooth any
remaining rough areas. If you sand through the base coat you must
re-establish a coat of U-66 urethane at that point and allow to cure.
Apply second coat of urethane at the rate of one gallon per 125 square
fast. Hand broadcast nut-shell granule into the wet coating to completely
and uniformly cover surface. Approximately five pounds of granule are
required for each 100 square feet. Coat and sprinkle small areas at a
time, taking care not to overlap coating and granule at edges. When
texture coat is dry enough to walk on (usually 24 to 36 hours), sweep away
loose granule.
7. TOPCOAT
Apply third coat of U-66 in desired final
color over granule at the rate of one gallon per 75 square feet. To
minimize roller marks, try to roll this coat in two directions at 90
degree angle to each other, but always finish by rolling in the same
direction
8. DRYING
After final coat, allow at least 48 hours
drying time before deck is put into use. In cool temperatures, a longer
drying time will be required.
9. THINNING AND CLEANING
U-66 urethane coating cures rapidly and the
cleaning of roller covers and brushes is usually impractical. Use T-5116
thinner for cleanup of hands and for thinning of material when an
extension of pot life is required. Do not thin more than 10 % (less than a
pint per gallon).
For More Information
Call "The Waterproof Coating Experts" sm
@ +1.503.345.9338
Toll Free @ 1.888.513.DECK (3325) (U.S. Only)
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