.
FINISHING AND FLYING
The photo of Glen's Smith was constructed in 1967 by Billy Simpson of
Jerseyville, ILL. His expert workmanship is evident by the dazzling, high gloss
red, white, and black paint job. The Miniplane's construction is typical of many
home-built designs - with steel tube, fabric covered fuselage and tail surfaces;
wood and fabric wings; metal cowl; and fiberglass wheel pants.
16.
Sanding And Painting Plastic Parts
All of the ABS plastic parts should be sanded to remove the gloss on the surface
of the plastic before they are painted. Avoid using coarse sandpaper which can
deeply scratch the plastic.
Deep scratches can open up during doping and become prominent. Use something like 220 grit 3M Tri-M-Ite Free Cut
Finishing Paper (See Sig Catalog). Polish down the first sanding with 360 grit Free Cut Tri-M-Ite or 400 grit Wet-Or-Dry
paper before color doping.
The plastic parts may be brushed or sprayed with Sig Supercoat color dope. Care should be taken not to apply heavy, wet
coats of color dope to the plastic. Put on light coats and allow them to dry thoroughly before applying a second coat.
The ABS plastic parts may also be painted with K&B Super Poxy, Hobbypoxy, or
DuPont Dulux Enamel. Do not use other paints, dopes or finishes without first
testing on scrap plastic to make certain they are compatible with the plastic.
NOTE: Do not try to cover any of the plastic parts with monokote or other iron-on
types of covering material. The heat can damage the plastic parts.
17.
Covering And Painting
The Miniplane should be covered with silk, or other cloth material, rather than silkspan, due to the large unplanked areas.
Remember that covering and paint won't cover up poor workmanship - Be sure all surfaces are smooth. After the final
sanding of the finished framework give it two coats of unthinned dope wherever you want the silk to adhere to the
framework. Give these areas another final, light sanding. Apply the silk wet but do not stretch too tightly, as it will only
encourage warping later on. Pull the silk up just enough to get out all the slack and wrinkles. Paint dope around the edges.
This will soak through and adhere to the pre-doped framework. Let dry before trimming with a sharp razor blade. Check for
any spots that are not stuck down and apply more dope.
Next give the entire airplane three coats of Supercoat Clear Dope or Lite-Coat
Low Shrink Clear Dope. Thin the dope until it brushes on easily and flows out
smoothly. Brush on the first coat over the open areas sparingly. As the brush
rubs across the ribs, dope is rubbed off the brush and through the silk and will run
down the ribs inside. As excessive amount will run completely through the
framework and puddle against the covering surface on the other side. When
these puddles dry, the large amounts of dope solids in them causes more
shrinkage than in the rest of the covering and a scarred area results. So apply
dope very lightly the first time over. A second coat should seal most of the pores
of the silk and from this point, running through will not be a serious problem.
A fourth or fifth coat of dope may be necessary, depending on how heavy a coat
is applied, to completely fill the silk grain. The ideal is a completely smooth and
even base.
Keep in mind that weight can build up fast in finishing and restraint must be used in application. Sand lightly with 220 grit
Tri-M-Ite paper between the later coats of dope. Don't bear down on the edges of the balsa structure or the silk fibers will
be cut.
