Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 27)

D D 2. Glue a die-cut 1/8" plywood cabin side to the
fuselage side.
D D 3. Remove the fuselage side from the plan and
inspect the glue joints for gaps, filling where necessary with
thick CA.
D 4. Repeat steps 1-3 for the other fuselage side. When
completed, place both sides together and sand the edges
to make the pieces identical. Designate a right fuselage
side and a left fuselage side at this time. Mark the sides to
avoid building two "rights" or two "lefts" in the proceeding
steps. Rough sand the inside and outside of both fuselage
sides with 150-grit sandpaper.
D D 5. Use thick CA to glue a die-cut 1/8" plywood lower
fuselage doubler to the inside of one of the fuselage
sides. It must align at the front and bottom edges.
D D 6. Use thick CA to glue the die-cut 1/8" balsa upper
fuselage doubler to the same fuselage side. The front and
top edges of the doubler should be flush with the edges of
the balsa fuselage sides.
D 8. Return to step 5 and add the doublers to the inside
of the other fuselage side. Be sure to make a right and a
left side!
D 9. Test fit the two die-cut 1/8" balsa aft fuselage tops
together. Sand them if necessary to achieve a good fit,
then glue them together with medium CA.
D 10. Use the aft fuselage top as a gauge to position the
die-cut 1/8" plywood cabin doublers. The bottom of the
doubler should be above the fuselage side by the thickness
of the aft fuselage top. The aft edge of the vertical slot in
the cabin doubler should be even with the aft edge of the
cabin, and the top edge must be flush with the top of the
cabin side. Once you have determined its exact location,
trace a line around the doubler so you can accurately
position it after you have applied thick CA. Glue a doubler
to both fuselage sides. Don't apply any CA to the area of
the doubler aft of the cabin side.
D D 7. Use thick CA to glue a die-cut 1/8" balsa aft upper
fuselage side, then the aft fuselage doubler in place.
The doubler should match up with the corner made by the
aft fuselage side and the aft upper fuselage side, and line
up with the top edge of the aft upper fuselage side.
D 11. Remove any die-cutting irregularities from the die-cut
1/8" plywood firewall formers 1A, 1B and 1C. Separately,
drill two 1/8" holes through the punch marks in each firewall
doubler for the 1/8" x 1" firewall alignment dowels.
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