4. Continue to
duplicate this process until you have obtained a part thickness appropriate
in strength
for your intended purpose. Yes, I know that sounds ambiguous, but you are the only one who
can determine the strength and flex attributes of the sandwich. Wipe each sandwich layer
with alcohol before applying the next layer of cloth and resin. Epoxy releases waxes when
it cures. If this wax is not removed, there will be insufficient bonding of
subsequent
layers. Copying a second set of template will aid in the final shaping of the parts.
You
can clearly see the original template beneath the resin and cloth. It is easy to align the
second set of template with those you adhered to the aircraft's surface. You can affix
these top template with a single drop of CA adhesive which will be sanded off during the
finishing phase. When the top template is affixed, pick the entire finished sandwich from
the aircraft surface. note that it has taken the contour of the aircraft's surface. Cut
along the template edge with a hobby knife or rotary tool, taking care to not cut into
template shape.
Sand surface of the formed
part with 100 grit wet-dry no load sandpaper. Take care to not gouge or scratch the epoxy
surface layer to retain a metallic texture for the part. After cleaning with alcohol one
last time, blow dry the part. Lay the finished part onto aircraft's surface aligned with
the still adhered original template.
With a polymer lead pencil, trace around the finished part's perimeter. Cut out the traced
template, including the perimeter line. This provides clearance for the hatch, door or
panel. Attach the finished part so it will function appropriately. In the case of the
speed brake for the SU-27, you
could control this surface with the throttle, flaps or separately depending on the
maneuver combination you plan to utilize a speed brake with. Just the attachment process
is another Details© article all by itself! Good luck and good flying! |
© '98, '99, Y2K,2005