Applying the Plaster
For most walls, the recommended application is two thin coats—a base coat
1/32" to 1/16" thick of Loma, followed by a 1/32" finish coat of either Loma,
Porcelina or Marittimo (about the thickness of a credit card). Over drywall,
for example, the base coat should be 1/32" thick. Stuccoes or brown-coated
surfaces will require a slightly thicker base coat. For all substrates, do not
exceed 1/32" for the finish coat.
The sections below describe application with a trowel. If you are using spray
equipment to apply the plaster, spray for complete coverage then trowel the
surface or texture it to the desired finish. See the American Clay Instructional
Video for more information.
APPLYING THE BASE COAT
(The base coat is always Loma regardless of your finish coat choice)
If you’ve applied an undercoat of American Clay Sanded Primer, do not mist the surface before plastering. Mist all other surfaces lightly with water.
 1. Place a comfortable amount of plaster onto a ‘Hawk’. Scoop a small amount of plaster from the ‘Hawk’ onto a trowel.
2. Starting at the bottom of the wall, spread the plaster with the trowel held at a 15° to 30° angle.
3. Work the plaster out on the surface of the wall until you have a smooth, thin coat. Don’t rush—American Clay Earth Plasters have long working time and are very forgiving.
4. Using the same techniques, apply plaster in sections, always troweling on new plaster next to a section whose edge is still wet. Do not overwork the base coat—leave a slightly roughened texture on this coat so it has a “tooth” to which the finish coat can adhere.
5. Continue applying plaster to all walls. If you have to break your work into sections, always finish applying the base coat to one complete wall. Cover the plaster in the bucket during breaks so it retains its moisture.
 6. Let the base coat dry. In no case should you apply the finish coat to a base coat that has not dried completely. If the base coat is not completely dry, the finish coat is likely to crack.
APPLYING THE FINISH COAT - AMERICAN CLAY LOMA
Many of the special effects American Clay plasters will produce are the result
of varying the application of the finish coat or applying techniques while
the finish coat is still pliable. Different finishing tools will produce different
effects. We have listed the most common procedures below.
Make sure the base coat is dry before applying the finish coat.
 Trowel on the finish coat (maximum 1/32") rewetting areas
of the base coat as needed. We do not recommend wetting
the base coat before applying the finish coat. If the plaster is “setting up” too fast, then misting the base coat can help.
Finishing an American Clay Earth Plaster after the finish coat dries compacts
and strengthens the surface, reduces trowel marks and prevents dusting. For
the product to be easily repairable this is critical.
Option 1: for a MATTE FINISH –
A. Let the finish coat dry until it is damp but firm enough that slight pressure
from your thumb won’t leave a thumbprint. Then lightly mist the  surface
and remove trowel marks (as desired) with a trowel held at a
low angle (but not flat). Do not over-wet the surface during
this step.
B. If surface cracks appear as the finish coat dries, mist them
lightly with water and compress the cracks with your trowel.
 C. Let the finish coat dry.
D. Using a well-wrung-out (nearly dry) tile sponge and with
only light pressure, work the entire wall in overlapping
circular patterns, compressing the surface and removing any
of the loose sand.
Option 2: for a SANDED FINISH –
A. Let the finish coat dry until it is slightly resilient (will leave a thumbprint
with mild pressure). Then lightly mist the surface and rub it with a tile
sponge or stucco float. Do not over-wet the surface during this step.
B. Let the finish coat dry.
C. Using a well-wrung-out (nearly dry) tile sponge and with
only light pressure, work the entire wall in overlapping
circular patterns, compressing the surface and removing
any of the loose sand.
Option 3: for a HARD-TROWEL FINISH –
 A. Let the finish coat dry until it is damp but firm enough that
slight pressure from your thumb won’t leave a thumbprint.
Then lightly mist the surface and remove trowel marks with
a plastic trowel held at a low angle (but not flat). Do not over-wet the surface during this step.
B. Let the finish coat dry completely.
C. Then lightly mist the surface of the finish coat with a spray
bottle.
 D. Using a polycarbonate (lexan) or acrylic (plexiglass) plastic
trowel and with steady pressure, re-trowel the surface in
broad, overlapping arcs.
E. Repeat steps B, C and D until the desired smoothness and
mottling is achieved.
Option 4: for a SKIP-TROWEL FINISH –
A. Lightly mist the base coat with a spray bottle.
 B. Trowel on a finish coat (maximum 1/32") of American Clay
Loma, leaving open areas that reveal the base coat in the
pattern of your choice. The “skip” pattern can be as “sparse” or as "busy" as you wish, from several inches to a foot or
more. As you trowel on the finish coat, compress the plaster,
but do not cover the areas of the base coat you want
revealed.
Let the finish coat dry.
C. Lightly mist the finish coat areas and work them with a plastic trowel to
smooth the surface or use part “C” from “For a Sanded Finish” above to
produce a coarse finish in the finish coat.
Regardless of how you have finished the finish coat of American Clay Loma,
let the surface dry a minimum of 12 hours.
Regardless of how you have finished the finish coat of American Clay Loma,
let the surface dry a minimum of 12 hours.
APPLYING THE FINISH COAT - AMERICAN CLAY PORCELINA
Note: this critical step compacts and strengthens the surface, reduces trowel
marks, and prevents dusting.
BURNISHED FINISH—
"Burnishing" a plaster finish refers to any process used to give it a polished
sheen. American Clay Porcelina does not require burnishing with fine grit
sandpaper. It only requires retroweling.
A. Apply American Clay Porcelina over a base coat of American Clay Loma to a
maximum thickness of 1/32", troweling the surface evenly.
B. Let this finish coat dry.
C. When the finish coat is dry, rub it with a barely-damp sponge or lightly mist
the surface, then work it with your trowel. Use a stainless steel trowel for
dark colors, and a plastic trowel for light colors.
D. Before the surface dries, retrowel the surface, using fast arcing strokes. If
the trowel is “sticking or grabbing” the plaster, it is too wet. Let the water
evaporate for 10–30 seconds before proceeding with the burnishing.
APPLYING THE FINISH COAT - AMERICAN CLAY MARITTIMO
Note: this critical step compacts and strengthens the surface, reduces trowel
marks, and prevents dusting.
A. Apply American Clay Marittimo over a base coat of American Clay Loma to a
maximum thickness of 1/32", troweling the surface evenly.
B. Let this finish coat dry.
C. When the second coat is dry, mist the surface lightly, then, compressing as
you go, work it with a stainless steel finishing trowel for dark colors and a
plastic trowel for light colors.
D. Allow this reworked surface to dry and lightly rub with a nearly dry sponge
in a random but complete pattern over the entire surface to reveal the shell
and patina glow.
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