In a message dated 7/9/2009 3:02:51 A.M. Eastern Daylight Time,
europa-list@matronics.com writes:
>>>>>Cars and store bought airplanes are metal, blistering is a composites
problem. If there are any fingerprints, unreacted resins, whatever, on
the surface before painting osmosis will occur. ALL paint systems are
permeable. As you say, wax is best<<<<<
Hey Graham,
Yes, a lot of them are metal, but blistering can occur on metal airplanes,
too. My father owned a Mooney back when I was a teenager. The airplane was
less than 2 years old and developed blisters on both wings. He sent it back
to the factory in Texas to have it fixed and unfortunately, it was
destroyed in a hail storm. Although that airplane sat out in the weather
constantly the blistering probably had little to do with rain and everything to
do
with paint preparation. Gel coat is bad about blistering on boats that are
in the water constantly. I've owned a couple of sail boats that were docked
permanently in water and both developed blisters on the hull below the
waterline after a while in the water.
>>>>>I always wanted to use a polish for extra protection=2C but I am
afraid tha
t it would be very difficult to do any future touchups. My experience with
furniture lacquers is=2C that it is very difficult to re-finish a tabletop
where any polish was used containing wax or silicone=2C even when it is str
ipped down to the bare wood.<<<<<<
Hey Karl,
The one thing you want to avoid at all costs is any finish enhancer that
contains silicone. That goes for DOT 5 brake fluid, too. Silicone is
extremely hard to get off once it's on the finish. Even sanding thoroughly won't
get it all off. There are silicone removers available. Most major paint
manufacturers make them in one form or another. We've tried a variety of them
with mixed results. Repeated wiping with acetone in between sanding seems to
work best, but we still get paint rejection from time to time. It's a real
bitch sometimes and requires several cycles of painting and sanding to get
the paint to stick if silicone is present. We've never had problems with
bubbling or paint rejection after we got the paint or gel coat to stick,
though.
>>>>>>Your experience seems to indicate that this is not a problem with
glider an
d Europa finishes. Can you confirm that and let us know what you use to pre
pare the surface for re-painting ? I never used carnuba wax. Is it availabl
e in car shops=2C and do I need a powered polisher for application ? Which
polishes are to be avoided ?<<<<<<
Carnuba wax is a high quality car wax and it seems to produce the best
results. We use it on both urethane and gel coat finishes. Wx Block is also
good, but it's pricey. Some folks prefer wax, others like Wx Block.
Personally, I like wax better because it shines better. You can usually find a
good
Carnuba wax at any decent auto parts store. Expect to pay around $10-$12 a
tin for it. We use the paste type Carnuba. Carnuba also will wipe off with
acetone and/or sanding.
We tell folks to avoid anything with silicone, sillica or similar
ingredients, though. Use of such products will be troublesome later on if you
need
to do a repair. As I previously mentioned this is why we do not recommend
furniture polishes for canopies, but rather plexiglass wax. Canopy rails are
usually the first place paint or gel coat will chip because they flex and
there are different expansion and contraction rates for the fiberglass rail
and the plexiglass canopy. This usually causes a crack to form at the edge
where the two meet. Chips usually follow. Silicone products, even though
they are slippery, also seem to tend to hold a slight electric charge which
tends to cause dust to stick to the surface. We saw that one play out a
couple of years ago at a glider meet out in Uvalde, TX. There was one guy in
the field of competitors who wiped his whole glider down every day with
furniture polish. Uvalde is desert conditions and there is a lot of dust. By
the end of the meet his glider was a dust magnet. No one else at the meet was
having the problem.
The wax is applied by hand, but you don't necessarily have to use a buffer
once it's ready to wipe out, but it does help melt the wax and gain a
better application and a much better shine. I would not use an orbiting type
buffer, though. Those type buffers will create swirls in your paint. We build
our own buffers out of a variable speed 7" die grinder. We use 9" flannel
buffing pads stacked up about 5" thick. You can get "threaded collars" to
fit the arbor of the grinder at virtually any hardware store to lengthen the
grinder arbor shaft by about 3". First, put on a big fender washer, then
the collar. Then, we add about 5" thick of 9" flannel buffing pads to the
shaft. We really pack the pads on the shaft and sometimes it involves using a
hammer to beat them onto the shaft so they are good and tight. Then,
another big fender washer and a bolt that mates to the other end of the
threaded
collar. Buffing is done end on. This way it does not create swirls, only
shine.
You have to pay particular attention when you are buffing control surfaces
and near leading and trailing edges. It's best to buff those parallel to
the wing or control surface for safety. If you buff 90 degrees to the control
surface or wing edge and aren't very careful it's easy to catch on the
edge of a wing or control surface like an aileron or elevator if you don't
pay attention to the direction of rotation and you can damage the surface. I
also "bump" the trigger repeatedly so that the buffer doesn't get going too
fast when I'm near the edge. Some grinders spin too fast for buffing, so we
use a router speed control to provide better control the RPM.
When buffing near the edge make sure the direction of rotation is outward
---From the surface's edge. If the rotation is inward toward the edge you
risk the buffer grabbing. I've twice seen ailerons literally torn off by folks
who weren't paying attention. You don't have to put much pressure on the
buffer, either. Usually, it's own weight is enough to do the job. It will
give your forearms a good workout, though. I can send you some pictures of the
buffers we use if you'd like.
Hope it helps!
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Flying
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