Carl Goldberg GBGA0059 - Manual (Page 23)

23
PREPARATION
Any irregularities in the wood sur-
face will show on the covering, so
a good covering job MUST be
preceded by careful sanding, fill-
ing of nicks and dents (we recom-
mend JET Model Mate™ balsa
filler), and then more sanding. For
the final sanding, use fine sand-
paper (240-320 grade) and a
sanding block.
IMPORTANT: Before starting, it's a good idea to do a
lay out of the covering pieces you will need to cut from
the covering rolls, so that you make efficient use of
your material. BE SURE TO LEAVE EXTRA MATER-
IAL (1½" to several inches) around all pieces, so you
will have plenty of covering to go around the edges of
each section.
Generally, one first covers the wing, then the tail, and
finally the fuselage. Other small parts (such as the
hatch) are covered separately.
Set the covering iron to the proper temperature. Test it
by laying a small strip of covering over a scrap piece of
balsa and firmly pressing with the iron. Make sure the
iron is hot enough to activate the adhesive, but not so
hot that it burns the covering.
COVERING THE WING
Using a fresh model knife blade or razor blade, cut a
piece of covering material at least 1" larger than one-
half of the inboard wing bottom panel.
Remove the protective backing paper and lay the cov-
ering over the bottom of the wing, making sure there
is enough excess material for wrap-around at the L.E.,
T.E., and wing tip.
HINT: Leave a minimum of 3" excess at the wing
tip.
For inside corners, follow the instruction that come with
your covering, as different materials may require slight-
ly different techniques.
Using your iron, secure the covering to the wing.
Shrink the covering tight according to instructions.
Neatly trim off any surplus.
Following the same procedure, cover the remainder of
the wing bottom and then cover the wing top. Be sure
to overlap all seams adequately, as there must be suf-
ficient overlap to allow for the shrinkage.
OVERLAP COVERING AT
SEAMS. SEAL INBOARD PANEL FILM TO
SIDES OF RIBS. DO NOT SHRINK
INTERIOR AREAS UNTIL WHOLE
WING IS COVERED.
AFTER ALL EDGES AND COLOR JOINTS ARE SEALED,
SHRINK ENTIRE WING COVERING
To detect warp,.set each section of the wing on a flat
surface and make certain the panel sits flat. To counter
any warp, twist panel slightly in the direction opposite
to the warp and hold this position while gliding the iron
over the covering to re-tension the structure. Repeat
process until the panel is true. NOTE: The T.E. of the
wing tip will rise up about 1/4" from the flat surface.
1/4" WASHOUT
POLYHEDRAL JOINT
TRUING THE WING & SETTING WASHOUT
IMPORTANT: After the wing has been covered, you
must check to make sure it is free of warps. This is a
very critical step and should not be rushed or
omitted.
COVERING THE TAIL & FUSELAGE
Cover all tail components (the stabilizer, the elevator,
the fin, and the rudder), following the same procedure
as with the wing. The component pieces should each
be covered separately, before assembly. Then, the
covering should be carefully removed from the areas to
be glued, so that a strong WOOD-SURFACE-TO-
WOOD-SURFACE adhesion is achieved.
Cover the fuse bottom, sides, and finally the top, again,
making sure the pieces are large enough to allow for
overlap.
IMPORTANT: Once the tail sections have been cov-
ered, and while the hinge locations are still fresh in
your memory, IMMEDIATELY slit the covering to
open up the hinge slots. (Refer to the plan for help
in locating the hinge slots.)