.
Go back over the side seams with the iron and then seal the covering to HR at the front as well as F-6 and the tail fairing
blocks at the rear. Trim away the excess covering at the rear flush with the edges of the fairing blocks and F-6. At the
front, leave a 1/8" overhang to the front of HR. Fold the overhang to the front of HR and seal down. Use a heat gun or iron
to shrink the material tight over the stringers.Think about covering or painting the headrest (HR) and the cockpit floor with
another color like grey or black, to set off the cockpit area.
Covering The Tail Surfaces And Ailerons
The stabilizer, elevator, fin, rudder, and ailerons should each be covered with two pieces of material - bottom first, then
top. Iron the material from the center out to avoid trapping air bubbles. Be sure to cover the back edge of the fin trailing
edge all the way to the bottom.
Covering With Sig Koverall And Dope
KOVERALL is a polyester-based heat-shrinkable, synthetic fabric much like the covering used on full-scale aircraft, only
lighter. Its toughness and relatively low cost make it ideally suited for sport models or giant scale aircraft. One large
package of KOVERALL (48" x 5 yards) is plenty of material to cover most models. It can be applied to the structure using
dope or SIG Stix-it, a heat-activated adhesive.
Surface Preparation
Whichever application method is used, you should first brush two coats of clear dope onto the framework wherever the
covering material makes contact - even the edges of the wing ribs. If dope is going to be used for the entire finish, apply
SIG LITE-COAT (low-shrink butyrate dope) for the first two coats. If enamels or epoxy colors are going to be used, apply
SIG NITRATE dope for the first two coats. Lightly sand after each coat to remove any raised grain or fuzz.
Applying Koverall With Dope
The bottom of the wing panel is a good place to start covering. Cut a piece of material about an inch larger all around the
panel, with the grain running spanwise. The grain of KOVERALL runs parallel to the finished edge. Lay the KOVERALL on
the wing, pulling out any major wrinkles. KOVERALL has considerable shrink when heated, so there's no need to worry
about packaging fold creases because they will disappear when the KOVERALL is shrunk. Pull the KOVERALL snug
across the root of the wing and brush clear dope along the tight edge. The dope will soak through the fabric, adhere to the
dope already on the framework and lock the fabric in place. When the dope has 'set' move to the wingtip and snug up the
fabric spanwise and chordwise and brush clear dope through the fabric. Repeat the tensioning, doping sequence all
around the rest of the wing. Allow the dope to dry before trimming off the excess material with a sharp razor blade. Check
for any rough edges or places that are not stuck down properly and apply more dope. Let the dope dry thoroughly before
applying the next piece of fabric. This process continues until all the parts are covered.
Any parts that are going to be glued in place at a later time should have the glue areas masked off to preserve the bare
wood and enhance the adhesive properties of the glue.
Applying Koverall With Stix-It
Directions for using STIX-IT are on the can. The basic procedure is to apply STIX-IT around the edges of the framework
where you want the covering to attach. When dry, the fabric can be ironed-on around the edges where the STIX-IT was
applied.
Shrinking And Sealing Koverall
After both sides of a surface are covered, shrink the KOVERALL evenly with an iron or heat gun. It is possible to 'burn'
KOVERALL with too much heat, yet not show any damage. Heat the KOVERALL only enough to get the tautness needed.
It is possible to badly warp lighter structures because of the high level of shrink obtainable.
The fabric is now ready to be sealed with clear dope. The dope that you apply to the top of the fabric will soak through and
bond with the dope underneath, firmly cementing the KOVERALL in place.
Thin the dope until it brushes on easily and flows out smooth (25% to 30% thinner.) The first coat should be applied
sparingly to avoid puddles underneath the fabric. The second coat will seal most of the pores of the KOVERALL, from then
on running through will not be a problem. Sand the edges of the KOVERALL very lightly with fine sandpaper after the
second coat is dry. It may take three to five coats of clear dope on the KOVERALL before going to color, depending on
how heavy the coats are. The type or quality of finish desired will determine when enough clear dope has been applied.
Keep in mind that weight can build up fast when painting! Generally, don't bother trying to completely fill the weave and
avoid using heavy sanding sealer or primers. The goal is to hide the seams and provide an even base for the color paint.