REFLECTOR: Painting with Awlgrip

Bob Jackson bobj at computer.org
Sat Jul 2 02:18:21 CDT 2005


Hello Ronnie,

Glad to hear you're painting now with AWLgrip -- here are my comments and
questions:

a)  you've got to wait at least 30-45 minutes between coats, i.e., for them
to "flash off" first before going on to the next coat.  Waiting longer helps
reduce the chance for runs.  We've usually been waiting 1 1/2 hours or so.
If you don't wait long enough the next coat may not be able to flow and
flatten properly.  I've had problems with what look like dry areas when
coming immediately back over an area just painted, even though I'm sure
there should be plenty of paint there.  In this manner, the early second
coat may have created the "seeds" for the third coat orange peel.  How long
did you wait between coats?

b)  The AWLgrip literature says the first coat should be slightly wet, with
the next coats (what sounds to me like full-) wet coats.  I know Scott said
he had good luck with a full wet first coat, then lighter and lighter second
and third coats.  But, I think if you shoot too dry of a second or third
coat, there won't be enough there to re-flow and level out, perhaps in this
way you created the orange peel by not getting enough on with the second
coat.

c)  the first coat seems to be the key for us in minimizing orange peel.
It's got to be what I would call a full wet coat otherwise it forms the
"seeds" for later orange peel.  Also, I think I get the best coats if I put
each on in a single pass.  Common practice would dictate putting a coat on
in two passes, each perpendicular to the other to ensure a more even
coverage.  But with AWLgrip the second pass, even though just a few minutes
from the first, can look dry and doesn't always seem to flow in with the
first pass.

d)  I like 30% reducer for similar temperature and humidity conditions to
yours, like we get here in Florida.  This seemed to be a key for us in
minimizing orange peel.  But the literature says if you reduce beyond the
recommended 20-25% you will need three, not the more usual two coats to get
the required thickness.

e)  I've been told that 10 psi is the maximum you can use and still be
considered HVLP.  We've been using 6 psi.  You may possibly be getting too
much paint (and air) out at 10 psi and somehow that's contributing to orange
peel.

f)  Why did you paint just single sides of each control surface?  You can
not blend together coats of AWLgrip where coat edges meet, like on the
leading edge of the elevators.  We've been hanging ours up, with extra lines
to prevent them from turning from the force of the spray, and painting the
entire control surfaces in one step.  AWLgrip is not like two step paints --
it's a base coat and top coat all in one (unless you're using AWLgrip 2000,
which is a two step version).  There is no way to buff out the seams and
overspray areas between two adjoining AWLgrip coats.

g)  Are you sure about the 40 sq ft and 29 ounce numbers?  My rough
calculation for what you said you painted was only about 27 sq ft, but using
your 40 and 210 sq ft/gal number, 40/210 x 128 oz = 24 oz.  Also, although
we haven't keep accurate usage numbers, I was thinking we were getting more
like 300 sq ft/gal coverage, but I could be wrong on this.  It depends a lot
on the spray efficiency you're getting (how much overspray).  With smaller
items like you painted I think efficiency might be a little higher than with
large areas like wings and fuselage because it's a more "controlled"
situation.

h)  AWLgrip seems to be touchy WRT orange peel, but one thing to remember is
that once it drys and you take it out into the direct sunlight, it becomes
much harder to see the orange peel.  AWLgrip has such a deep shine, and with
the diffuse light of direct sun, you tend not to see the orange peel.  I
think that's why we've been advised that the worst error is the "drys", not
orange peel or runs which are harder to notice in the sunlight.

We'll be AWLgrip painting the fuselage tomorrow morning -- I'll let you know
if we learn something more new from that.  With the temperatures now in the
90's, the AWLgrip literature also says we should be using almost 50/50 blend
of T003 and T005 reducers.  I think this is to avoid too fast of solvent
evaporation and the resulting "solvent pop" pock marks, which we've seen
almost none of so far.

Good luck,
Bob Jackson


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Ron Brown
Sent: Friday, July 01, 2005 5:12 PM
To: reflector at tvbf.org
Subject: REFLECTOR: Painting with Awlgrip

I shot the bottom of my control surfaces today.  Temperature was 91 but with
humidity of 49%

I got a beautiful first coat - light but wet finish.  The second coat was
shot after it started getting tacky.  It came out a little dry looking -
still trying to keep it from getting too thick.  The third coat, light again
but wet turned into orange peel.

Did I shoot the first coat too wet?  I used the standard reducer in a HF
HVLP gun (10 psi on the regulator) and mixed the reducer to 30%.

By the way, after shooting the 3 coats, I still had 6 oz left.  I calculated
the standard coverage of 210 sq feet per gallon.  I shot the bottoms of the
control surfaces, one side of each rudder and the main gear leg doors.
Equals 40 sq feet and calculated to take 29 ounces of mixed paint but only
needed 23 ounces to cover with three coats.

Thanks for the help AND HAVE A HAPPY FOURTH OF JULY!!!!
Ronnie



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