Hi John=2C
Thank you for the very comprehensive reply. I can't quite picture your home
made polisher.
I and I am sure others would be very interested in a picture if that is pos
sible. I have a random orbit variable speed 7" Bosch sanding tool=2C but wi
th afoam pad it can also be adapted for polishing.
Karl
From: TELEDYNMCS@aol.com
Date: Thu=2C 9 Jul 2009 09:15:21 -0400
Subject: Europa-List: Re: Bubbling paint
In a message dated 7/9/2009 3:02:51 A.M. Eastern Daylight Time=2C europa-li
st@matronics.com writes:
>>>>>Cars and store bought airplanes are metal=2C blistering is a composite
s
problem. If there are any fingerprints=2C unreacted resins=2C whatever=2C o
n
the surface before painting osmosis will occur. ALL paint systems are
permeable. As you say=2C wax is best<<<<<
Hey Graham=2C
Yes=2C a lot of them are metal=2C but blistering can occur on metal airplan
es=2C too. My father owned a Mooney back when I was a teenager. The airplan
e was less than 2 years old and developed blisters on both wings. He sent i
t back to the factory in Texas to have it fixed and unfortunately=2C it was
destroyed in a hail storm. Although that airplane sat out in the weather c
onstantly the blistering probably had little to do with rain and everything
to do with paint preparation. Gel coat is bad about blistering on boats th
at 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 afr
aid 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 tableto
p
where any polish was used containing wax or silicone=2C even when it is s
tr
ipped down to the bare wood.<<<<<<
Hey Karl=2C
The one thing you want to avoid at all costs is any finish enhancer that co
ntains silicone. That goes for DOT 5 brake fluid=2C too. Silicone is extrem
ely 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 man
ufacturers 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 t
o work best=2C but we still get paint rejection from time to time. It's a r
eal 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 wit
h bubbling or paint rejection after we got the paint or gel coat to stick
=2C though.
>>>>>>Your experience seems to indicate that this is not a problem with gli
der 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 ? Whic
h
polishes are to be avoided ?<<<<<<
Carnuba wax is a high quality car wax and it seems to produce the best resu
lts. We use it on both urethane and gel coat finishes. Wx Block is also goo
d=2C but it's pricey. Some folks prefer wax=2C others like Wx Block. Person
ally=2C 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=2C sillica or similar ingredi
ents=2C though. Use of such products will be troublesome later on if you ne
ed to do a repair. As I previously mentioned this is why we do not recommen
d furniture polishes for canopies=2C but rather plexiglass wax. Canopy rail
s 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=2C even
though they are slippery=2C also seem to tend to hold a slight electric cha
rge 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=2C TX. There was
one guy in the field of competitors who wiped his whole glider down every d
ay 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=2C but you don't necessarily have to use a buffe
r once it's ready to wipe out=2C but it does help melt the wax and gain a b
etter application and a much better shine. I would not use an orbiting type
buffer=2C 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" fla
nnel 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 lengthe
n the grinder arbor shaft by about 3". First=2C put on a big fender washer
=2C then the collar. Then=2C we add about 5" thick of 9" flannel buffing pa
ds to the shaft. We really pack the pads on the shaft and sometimes it invo
lves using a hammer to beat them onto the shaft so they are good and tight.
Then=2C another big fender washer and a bolt that mates to the other end o
f the threaded collar. Buffing is done end on. This way it does not create
swirls=2C 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 th
e 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 edg
e 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 a
lso "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=2C 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 bu
ffer=2C either. Usually=2C it's own weight is enough to do the job. It will
give your forearms a good workout=2C though. I can send you some pictures
of the buffers we use if you'd like.
Hope it helps!
Regards=2C
John Lawton
Whitwell=2C TN (TN89)
N245E - Flying
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