Extreme Flight 78" EXTRA 300 ARF Instruction Manual page 10

4. In this step I will outline the procedure we use to install the hinges. There are several
ways to do this and several adhesives you can use. We will describe the way we do it, as
this method has proven itself over many years of model building. If you are new to this
type of hinging process then I recommend that you install a single hinge first just to
acquaint yourself with this method. Before starting the process get a few items together
that will aid you as you proceed. You will need the following items: 30 minute epoxy
(we recommend Pacer Z-Poxy), a scrap piece of pushrod or 1/8" dowel, paper towels and
denatured alcohol. Locate 3 hinges per elevator half. You will need to cut 1 hinge just
beyond the second knuckle to clear the fiberglass tube socket in the stabilizer.
Insert the carbon fiber wing tube into the socket while testing for proper hinge length to
avoid damaging the fiberglass sleeve. Mix a generous batch of 30 minute epoxy. Use the
pushrod or dowel to thoroughly coat and fill the hinge hole with epoxy, then coat the
hinge with epoxy. Push the hinge into its hole until the joint is about a ¼" from its final
position and use a paper towel to remove the excess epoxy that has been forced from the
hole. Push the hinge the rest of the way in and make sure the hinge pin is centered
in the hinge line. Use some denatured alcohol and a paper towel to remove all excess
epoxy, especially on the hinge pin. When you are satisfied with the result set the surface
aside to dry. Position the drying piece so that any excess epoxy will pool around the rear
of the hinge. When you are comfortable with this process you should be able to do one
side of a surface per batch of epoxy. Glue all hinges into the stabilizer first. After the glue
has set trial fit the elevator to the stab and adjust if necessary. There should be as little
gap as possible between the stab and elevator. When satisfied with the fit remove the
elevator and repeat the gluing process outlined above. Be sure to wipe away all excess
epoxy! Set aside to dry. Repeat this process for the other stab/elevator half.
5. After the hinges have dried thoroughly, pull on them to make sure they are properly
installed. The hinges will probably feel a little stiff as it is almost impossible to get all of
the glue out of the knuckle joint. Use a fine tipped hypodermic needle and place one (only
one!) drop of acetone on each side of the hinge pin. Move the elevator back and forth a
few times and you will feel it loosen up. Be careful to only use one drop as you don't want
to weaken the glue joint! Add a drop of penetrating oil to each hinge pin and you will
ensure a smooth operating surface with no binding. Seal the bottom of the hinge gap with
a strip of Ultracote or Blenderm tape. Be sure to fully deflect the control surface when
applying the tape or Ultracote to allow full deflection once the gap is sealed. Repeat this
process for the other stab/elevator assembly. Before you set aside the stabs take a moment
with your covering iron and go over all of the seams with a medium heat setting, paying
special attention to the ends of thin trim stripes. At this point clean the 2 elevator/stab
assemblies with Windex and set them aside.
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