T
HERE are several types of epoxy suitable
for applying skins. To keep the weight
down, we need to use the minimum amount
of epoxy possible. This is easiest with the
low viscosity finishing resins. Most resins of
this type tend to have working times under
30 minutes. If you are familiar with vacuum
bagging, then this is not a problem. If this is
your first time, then you might want to
obtain a “laminating epoxy” with an hour or
more of working time. These are available
from most of the vacuum pump suppliers. Do
not
dilute the epoxy with any type of solvent.
Mix the epoxy according to the directions.
We use about 1 ounce to do an entire set of
wings. If you are using weights instead of a vacuum bag, you
might want to use about 1
1
⁄
2
ounces of epoxy. If you are using
a fast setting resin, it helps to pour most of it out on the skins
as soon as it is mixed. This will extend the working time.
Now spread the epoxy on the skins using a couple of old play-
ing cards as a squeegee. You should have some resin left for
the next step. Remember, the skin to foam glue joint does not
have to be any stronger than the foam core itself!
U
SING a felt tip pen, layout the position of
the
1
⁄
2
" fiberglass reinforcing tape on the
inside of the wing skins. The location of the
tape is shown on the plans. The exact posi-
tion is not too critical.
Cut the glass tape to the lengths marked on
the wing skins. Leave a half inch extra at the
wing root. Be careful when cutting the tape
since it will unravel
very
easily. Remember
that you only need 2 pieces of tape for the
trailing edge(left and right), while there are 4
pieces of each length (upper and lower, left
and right) for the other two lengths
It is a good idea to color the aft
3
⁄
4
" of each
wing skin trailing edge with a dark color
marker as shown in the photo. This will make it easier to find
the trailing edge center line when you are sanding it later.
If you are using a vacuum bag, now is the time to get it ready.
If you are skinning both wing halves at the same time, make
the bag at least 5 feet long. Re-read the manufacturers instruc-
tions one more time. Otherwise, make sure that you have at
least 100 pounds of weights, and practice stacking them on an
area the size of the wing cradles. Once you mix the epoxy, it
will be too late…
Mark location of glass tape
Color trailing edge of skins
Cut glass tape to length
Prepare vacuum bag
Phoenix
Page 8
Wing Construction
Prepare fiberglass tape
Mix the epoxy carefully
Spread epoxy on skins
Wear gloves
Don’t use too much glue
Apply epoxy to wing skins
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