Coverning with Rip Stop Nylon, updated March 13th, 2002

Covering a foam wing with ripstop nylon add immensely to its strength and impact resistance.  Ripstop nylon
is a tightly woven fabric that has a "grid" woven into the standard weave.

It is available at fabric stores like Hancocks and JoAnns for $3 to $5 per yard.  The bolt number is 128.  This
ripstop is coated with a resin to make it water resistant which also maks it harder for us to get it to bind to a
foam wing. In the following few paragraphs I will tell you how to get a good covering job with Ripstop.

After purchasing your ripstop look at it closely.  If you bought bolt #128 you will see that only one side is
coated with resin.  The resin side goes away from the foam.  The non coated side needs to go against the
foam.  You can tell which is which by looking at it closely.  The resin coated side is shiny and the uncoated
side has a dull or flat appearance.  When you cut the ripstop to fit your wing panels mark which side is the
inside with a ball point pen.

Lay the rip stop on your wing cores. Mark the ripstop for cutting so that the LE will overlap about one inch
and the trailing edge will have just enough excess for you to hold onto and pull during covering.   I use four
pieces to cover my Bat Trick wings because they have double tapers.  I make a bottom left, bottom right, top
left and top right.

Ripstop is tough to cut.  I bought an Ofna Rotary cutter and cutting mat at the fabric store.  This tool makes it
much easier to cut any covering material easily and cleanly.

The first step in covering is to put your ripstop in a pot of water and put it the stove to heat it up.  Let it sit in
hot water for at least thirty minutes.  The water doesn't need to be boiling, the max water temp you want is
one where you can still reach your hand into the pot to get the ripstop without scalding your hand.

There are several reasons for heating the ripstop in hot water.  First the heat makes the fabric expand.  When
it cools it will shrink out tightly on the wing.  Second the water expands the weave allowing the waterbased
polyurethane paint to get into the weave.  Third the fabric loses its stiffness and becomes limp and easy to lay
out and smooth out. I also put a dollop of water based polyurethane into the soup so it can start penetrating
the ripstop while it warms up.

Take your pot of ripstop soup out to your builidng area and set it where you can reach it.  Take your Water
Based Polyurethane and apply a heavy coat directly to the foam panel.  I use a two inch wide bristle brush
and brush about an inch on the bottom of the leading edge for the fabric to overlap on the leading edge.

Lay the ripstop down onto the wing core coated with waterbased polyurethane and use your hands and the
brush to work out wrinkles and bubbles.  Once the ripstop is down brush the leading edge fabric against the
foam.  Now comes the final part - put straight pins through the ripstop into the foam to hold it in place while it
cures.  It will shrink and pull away at the trailing edge if you do not do this.

Good Luck, Lou