Sand The Fuselage; Fuelproof The Engine And Fuel Tank Compartments; Prepare The Model For Covering; Cover The Stabilizer - GREAT PLANES PT40 User Manual

SAND THE FUSELAGE

D 1. Use your T-bar with 100 grit sandpaper to
sand the entire fuselage smooth. Pay special atten-
tion to the glue joints, as they will show right through
the covering if left bumpy or uneven. Round all edges
slightly, excepting the wing saddle area and the
hatch saddle area, to make it pleasing to the eye.
D 2. Now change to a T-bar with 220 grit sandpaper
and go over the entire fuselage again, final sanding
it very smooth.
FUELPROOF THE ENGINE AND FUEL
TANK COMPARTMENTS
Note: Most of the model's surfaces will be sea-
led and protected by the covering material you use;
however, the engine and tank compartments would
be difficult and impractical to cover, so you must pro-
tect these areas by brushing on one or more coats of
"fuel proof paint which is available from your local
hobby dealer. Or, instead of paint, you may mix up
some 30 minute epoxy, thin it to a brushing consis-
tency by adding a little rubbing alcohol and brush
it on.
D 1. Fuelproof the inside surfaces of the engine
compartment, including the engine beams, balsa
triplers, and the front of F-l.
D 2. Fuelproof the breakaway plates.
D 3. Fuelproof the inside of the fuel tank compart-
ment, including the bottom of the hatch.

PREPARE THE MODEL FOR COVERING

D 1. Check the fuselage and the wing for any dents
you might have put in the wood. A small amount of
water placed on the dings will repair them. The water
causes the balsa to swell, removing the dings au-
tomatically. Use balsa filler on larger dings. Sand
the balsa filler to a smooth finish using fine grade
sandpaper. You should have already final sanded your
PT40 but give it another sanding with fine paper.
The better the finish at this stage the better the
covering will look.
D 2. Wipe all the dust from the model with a tack
rag or vacuum with a hand held attachment. Tack
rags are sold at hardware stores and are chemically
treated so they will clean surfaces prior to painting.
D 3. Make sure all hardware, engine etc. is out of
the model so you can do a good job of covering.
NOTE ON COVERING TOOLS:
Since we recommend that you use a plastic cov-
ering such as Super Monokote to finish your PT40,
you'll need to be aware of the tools you'll need to
borrow or buy to apply the covering to the model.
The covering itself has an adhesive on the side that
goes toward the wood. The covering is heated so it
will stick to the wood. A sealing iron and a heat gun
were made expressly for applying this type of cover-
ing. You'll also need an X-Acto knife with a new blade
or scissors to cut the covering.
NOTE ON COVERING SEQUENCE:
We recommend that you start with the stab
bottom and then do the stab top, fin, elevator, rudder,
ailerons (if you built Wing B), the fuselage and then
the wing.
GENERAL COMMENTS
Pieces of covering are cut about an inch over-
size. The covering is laid into position on the bottom
of the part, such as the stab, after the backing is
removed. The covering is tacked (touched with the
sealing iron) in a few places along the edges, then is
sealed along the edges with the sealing iron, leaving
a small opening at one edge for a vent. Then the
sealing iron is placed over the rest of the covering in
from the edges, heating it. Quickly seal the area with
a small rag by lightly rubbing the area. Then seal
the vent you left open. If you get any bubbles, pick
them with a pin and reseal. Now seal the covering
around any edges and trim with your knife without
cutting into the wood. The top of the part is then
covered, overlapping the edges and trimmed under-
neath so you won't see the seam when the plane is
on the ground. Using this covering and these tools
is not really difficult but takes some practice to get
really nice results. So practice and you'll be pleased
how nice your models will look.

COVER THE STABILIZER

D 4. Start at the corner of the fuselage. Fold 1/4
inch of the covering up against the fuse side and
anchor it in place with your sealing iron. Then tack
and fasten the rest of the covering. You want to have
a good seal at the stab/fuselage joint so oil from the
engine exhaust won't soak into the wood.
COVER THE FIN, RUDDER AND
ELEVATOR
D 5. Use the techniques mentioned above and cover
these parts. The seal at the fin/fuselage joint is impor-
tant, so seal it well.

COVER THE FUSELAGE

D 6. Start at the bottom. The bottom covering
should overlap the sides by 1/4 inch. Lay the covering
in position, tack and seal the edges. Leave the tail
and nose open slightly for trapped air to escape. Now
use the heat gun and rag and fasten the rest of the
covering.
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