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 Why
do I need to be concerned about protecting my fabric from the sun?
>The ultra-violet rays of the sun will deteriorate
any fabric within a short period of time. Left unprotected,
polyester fabric will lose 85% of its strength within 1 year.
How
do I protect the fabric?
>The best blocking agent against the ultra violet
rays of the sun is aluminum pigment. We take the same formulation of
Poly-Brush and add aluminum pigment to it. It sprays on just like
the spray coats of Poly-Brush.
I
have heard the term "silver coats". What does that refer
to?
>Silver is another term for the Poly-Spray coats.
Some people refer to the aluminum coats as silver coats.
I
notice when I receive my Poly-Spray that it seems to have all of the
pigment settled on the bottom of the can. Is this a problem?
>This is a very definite problem. You must
thoroughly mix the pigment into solution. If you do not do this you
will not have adequate protection from the sun. The best method is
to take Poly-Spray cans to a local paint store and have them shake
them. Even then, just prior to mixing and spraying you should
thoroughly stir.
How
much Poly-Spray will I need for my airplane?
>An estimate is provided in the Poly-Fiber
covering manual. You will want to spray on a minimum of 3 cross
coats to ensure protection. Coverage of 1 gallon is approximately
200 square feet per gallon.
I
have had my Poly-Spray sitting on the shelf for over 3 years. Is it
any good?
>The shelf life of Poly-Spray is at least 4 years.
However, remember that the pigment will continue to settle with
time. You must completely mix the pigment.
Should
I thin Poly-Spray prior to spraying it on?
>Yes. Thin it 1 part of reducer to 4 parts of
Poly-Spray. Use either R75-75 Reducer or R8500 depending upon the
temperature.
What
about cleaning the fabric before applying Poly-Spray?
>You must clean the fabric before applying the
Poly-Spray. Clean it completely using C2210 Paint Cleaning Solvent.
Wipe it off with this chemical and then a final wipe using a tack
cloth.
I
notice that when I sprayed on the first coat of Poly-Spray I see a
lot of imperfections that I did not see earlier. Why is that?
>Poly-Spray will bring out all of the
imperfections. This is because of the darker color over the
Poly-Brush. In addition to protecting the fabric, Poly-Spray
provides a good, sandable fill coat for the topcoats that will
follow.
What
about using a chemical UV blocker in my topcoat instead of
Poly-Spray? Won't that save weight?
>You will save weight at the expense of not
completely protecting the fabric. UV blockers are not as effective
as aluminum pigment.
By
the way, how much weight will Poly-Spray add to the surface of a
typical airplane?
>The short answer is not much. A typical J-3 Cub
covered in Grade A cotton with dope chemicals will have a total
weight of fabric and chemicals of 75 pounds. The Poly-Fiber system,
with 3 coats of Poly-Spray weighs in at 45 pounds.
When
should I sand Poly-Spray?
>Spray on two full cross coats, let it dry
overnight and then sand. Start sanding with 280 grit sandpaper and
go to 320 grit sandpaper. You will wet sand. Do not dry sand.
Remember to stay off rib lacing areas, etc. when sanding. Dip your
sandpaper into a bucket of water and begin sanding. Be sure to wash
off all sanding residue and let the surface dry before applying the
next coat.
Where
should I sand?
>This is a good question. You must be careful
where you sand. Sand only in large, open areas and along the pinked
edges of tapes. Don't sand over rivet heads, sharp areas, etc. You
will sand through the fabric.
How
many more coats should I apply after sanding?
>One more cross coat is usually sufficient. You
can check this out by holding a 60 watt light bulb (protected by a
small cage) up to the fabric. Look through a cut out inspection hold
and see if the light is blocked. If you can see the light you need
an additional coat of Poly-Spray.
I
had to stop working on my project after putting one coat of
Poly-Spray on the surface. I have done nothing for 6 months. What
should I do before I spray on any more coats?
>You should lightly sand the Poly-Spray using 400
grit sandpaper. Then wash the surface with Poly-Fiber 310 cleaner
diluted in 20 parts of water. Let it dry and then spray a light coat
of R65-75 Reducer over the entire surface to soften it.
My
Poly-Spray dried real rough to the touch. What is the problem?
>Poly-Spray should dry with a smooth, semi-gloss
texture. If it is rough it is because the chemical dried before it
contacted the surface. This is known as "blushing". First
of all, be sure you are thinning the Poly-Spray properly. Move the
spray gun a little closer to the surface. You may have to add a
blush retarder (BR-8600) to the Poly-Spray. That will slow the
drying process.
What
about spraying on a cold or hot day?
>Do not spray in temperatures below 60 degrees F.
If the temperature is above 90 degrees F, you will have to use
retarder or wait until a cooler day.
The
edges of my finishing tapes are curling up as soon as I spray on
Poly-Spray. What should I do?
>You must be careful when fixing this problem. The
edges of tapes should have been ironed down after the Poly-Brush was
applied. Now you must be careful smoothing them. Use an iron
calibrated at 225 degrees F along with a piece of tinfoil as an
ironing shield. Do not touch the iron directly to the Poly-Spray. It
will leave unsightly marks.
I
am beginning to see pinholes as I spray Poly-Spray. What should I
do?
>This problem is created when solvents collect in
unfilled fabric weave. And then escape by causing a small blister.
If the weave has been properly filled during the Poly-Brush stages,
this will not be a problem. You must fill these voids. You can do
this only by using Poly-Brush. Mix 3 parts of Poly-Brush to 1 part
of reducer and then add 2 ounces of retarder per quart. Sand the
blisters to open the tops of the pinholes. Brush the Poly-Brush into
the pinhole areas. Spraying will not work.
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