Interior Finishing Products
How much compound and tape
do I need?
For every 3 sheets or 100 sq. ft. of 4ft X 8ft drywall you will
need; 30ft of CGC paper tape or CGC fiberglass tape; and 6kg of CGC
drywall compound.
What is the difference between
ready-mix compound and setting-type ( powder)
compound?
Ready-mix compound is ready to use out of the container. The
ready-mix may require a little mixing. Also, you may want to add a
very small amount of water, when you are doing the final (third)
coat finishing. Be careful not to add too much water. Setting-type
(powder) compounds are added to water (cold) and mixed to a
consistency of ready-mix compound. The mixing ratio is about 3
parts powder to 1part water by volume. Check the package for exact
amounts of water. Setting-type (powder) compounds set or harden in
the time period specified on the package ( 20,45,or 90 minutes).
The hardening action cannot be delayed by dilution with water.
Remember that setting-type(powder) compounds set quicker than
ready-mix, but they still need 24hrs to dry completely before the
final light sand and prime painting.
What is the difference between
Sheetrock and Durabond setting-type (powder)
compounds?
Both setting-type compounds have to be added to water and mixed to
the consistency of ready-mix compound. Always pour the powder into
the water. The Sheetrock products,20, 45 and 90 are easy to sand
when dry. The easy sand feature means sheetrock is more user
friendly. Durabond 45 and 90 are difficult to sand after drying and
must be smoothed before complete hardening. Durabond forms an
extremely strong bond when dry.
How wide should I make the
compound joint?
The first coat should be applied with a 5 inch taping knife
(127mm). The tape must be embedded into the compound. The compound
must extend beyond both sides of the tape. The first coat joint
will be approximately 5 inches (127mm) wide. Allow the joint to dry
24hrs and remove any imperfections with the taping knife. The
second coat is applied using a 8 inch taping knife (200mm). The
compound should extend beyond the first coat for a total width of 7
to 8 inches (178mm to 200mm). Allow the joint to dry 24hrs and
remove any imperfections with the taping knife. The third coat is
applied using a 10 inch wide taping knife (250mm). Press on the
knife so the compound fills depressions but does not significantly
add thickness. Feather edges 2 inches (50mm) beyond the second
coat. Allow to dry 24hrs, then lightly sand to form a smooth joint
that is ready for prime painting. The finished joint will be about
12 inches wide (305mm).
What kind of tape should I
use?
You may use either paper tape or fiberglass tape to finish a
drywall joint. When you use fiberglass tape, you must use
setting-type (powder) compound for the first coat. The second coat
may be finished with setting-type (powder) compound or ready-mix
compound. Fiberglass tape only requires two coat application when
finishing joints. Use proper joint finishing techniques to minimize
sanding and to produce a smooth joint. Paper tape may be used with
ready-mix or setting-type (powder) compound. Paper tape is easier
to use with ready-mix compound, because you don't have to worry
about the set time of setting-type (powder) compound, interfering
with your finish work. Paper tape requires three separate
applications of compound. Each application must be allowed to dry
24hrs. The first coat must fully embed the paper tape in the
compound. Any excess compound bulges must be squeezed out from
under the paper tape with the taping knife. The entire face of the
paper tape must be coated with a film of compound using the taping
knife. Complete the second and third coats using proper joint
finishing techniques to minimize sanding and to produce a smooth
joint.