REFLECTOR: Painting with Awlgrip
Ron Brown
romott at adelphia.net
Sat Jul 2 16:38:50 CDT 2005
Hi Bob and Scott,
Thanks for your replies!!! They are a big help!!!!!
Responses are below:
----- Original Message -----
From: "Bob Jackson" <bobj at computer.org>
To: "Velocity Aircraft Owners and Builders List" <reflector at tvbf.org>
Sent: Saturday, July 02, 2005 4:33 PM
Subject: RE: REFLECTOR: Painting with Awlgrip
> Ronnie,
>
> A few more comments:
>
> 1. Mixing Proportions. Did you weigh gallons of the AWLgrip topcoat, the
> converter and the reducer and they were all the same weight? I would be
> surprised, but I didn't try it. The directions say mix by volume, so if
> the
> densities are different, mixing by weight could change the proportions
> significantly. I would assume the topcoat is much denser than either the
> converter or reducer, and if so you'll be using too little converter and
> reducer, which contributes to orange peel -- on the other hand, it would
> minimize runs. Using 30% reducer by volume to minimize orange peel
> definitely makes runs more likely!
I did weigh the cans:
Cloud White is 11.44 pounds per gallon (subtracting .86 lb for an empty
can).
Converter is 8.39 pounds per gallon
Reducer is 7.41 pounds per gallon
My mixing "formulaes" are calculated using the above densities.
>
> 2. Partial Coats. I agree with Scott -- if you want to use AWLgrip, I
> would do everything possible (including 'exotic' wing stands, etc.) to be
> able to paint things like the canard, the control surfaces and the wings
> in
> one shot. I don't think you'll be happy with the overlap seams if you
> paint
> the bottom and top of the wing, for example, in two steps. In our case
> the
> very bottom of the fuselage at least will be a different color so we don't
> have to paint the entire thing in one step -- but if we were not doing a
> 'two-tone' design, I would definitely try to figure out some kind of rig
> to
> allow painting the entire fuselage (canard, wing, etc.) in one step.
>
The pieces I painted yesterday looked pretty good in the sun this morning.
I have picked up a little more trash than I expected using the home made
paint booth - filters on one end and exhaust fans (three cheapie Wally World
box fans) on the other end.
I painted the bottom of the canard this afternoon. My paint gun started
sputtering big drops of paint, so I had to stop and figure out what the
problem was. The tiny holes were stopped up, so I had to clean. I tried to
make the first coat lighter as the Awlgrip instructions say, waited a hour
and half, then laid on a heavier coat. Still got orange peel. But judging
from this mornings results, it should look better in the morning.
I hear what you are saying, but I'm not comfortable shooting the tops yet -
ain't pretty enough yet!!! And if I don't get the bottom of the wings
prettier than I am shooting, I'm going to hire a pro to shoot the top (or
perhaps give me some on site instruction). There are a couple of good
friends on the field that are good painters.
I'll let everyone know how the painting the bottom, masking the bottom and
then painting the top goes. I don't think the joint will be that
noticeable, but I'll certainly let ya know!
> 3. Problem Correction with AWLgrip -- not as bad as it seems. Even if
> you
> can't get all two or three coats of AWLgrip down without excessive orange
> peel, runs, or 'dry' spots doesn't mean you have to try over and over to
> paint all three in one clean series. I try to paint all three coats in
> one
> session, then if there's a problem, let it dry sand out the problem, scuff
> the rest (with 3M foam-sand pads, for example), and a couple of days
> later,
> paint a single, final, topcoat. So really, you only have to get one final
> coat right. Of course, if you're lucky and get all two/three coats on OK,
> then you can do the whole thing in one session.
Hmmmm. What grit sand paper are you using to scuff out the problems (runs,
orange peel, etc? And the foam sanding pads - what grit are they?
>
> 4. Anti Orange Peel Additive. Scott -- you mentioned the availability of
> this additive -- can you give us a part #? This could be very helpful,
> because as it is we seem to need 30% reducer to minimize orange peel, and
> that makes it more susceptible to runs.
Looking in my Awlgrip application guide - I only see T0005 which the book
says can improve flow at temperatures above 85 degrees. I did not see any
solvent pops so I think the T0003 is doing ok - but perhaps we may indeed
need to get some T0005??
> 5. Outside Temperature and Humidity. We have no choice in Orlando -- the
> humidity is almost always over 75% and often higher (especially when it's
> raining!!), so I'm not sure you should be too worried about that in
> deciding
> when/if to paint. AWLgrip 'standard conditions' are 77 deg F and 50%
> humidity, but that doesn't mean you can't use it successfully in other
> conditions.
In the hot hanger, no insulated roof, temps are running at 90 plus, which
along with dew points in the low 70's results in a RH of around 50% so I
think this is OK.
> 6. AWLgrip vs. Other Paints. To Al's question about the PPG paints -- we
> haven't done a physical comparison of AWLgrip with the PPG (or Dupont)
> paints. Obviously, you can achieve a great paint job with any of them. I
> believe that the AWLgrip 2000 version is more similar to the PPG Deltron
> and
> Concept. I think they're all 'acrylic' urethanes and two step paints
> (i.e.,
> the second step is a clear top coat). AWLgrip (and I think Dupont IMRON)
> are both 'polyester' polyurethanes, which are supposed to be quite a bit
> more durable and also flexible, which can be important for paint on
> airplanes.
And you have to remember, robots shoot the paint on the new cars. I'm an
engineer but no match for those paint spewing 'bots!!!
> Don't lose faith, Ronnie! If you can get the AWLgrip on (without orange
> peel, the drys, or runs) I think you will be very happy -- it looks great
> and is supposed to be extremely durable. We were not able to paint our
> fuselage this morning due to a thunderstorm. This is probably not the
> right
> time to be trying to paint a plane in Florida!
>
> Bob
>
>
> -----Original Message-----
> From: Ron Brown [mailto:romott at adelphia.net]
> Sent: Saturday, July 02, 2005 8:17 AM
> To: bobj at computer.org; Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Painting with Awlgrip
>
> Good morning Bob!
>
> You're up early or late going to bed! Thanks for taking the time for your
> excellent responses - I needed the moral support!!!
>
> I will comment on each of your items in the text below:
>
> ----- Original Message -----
> From: "Bob Jackson" <bobj at computer.org>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Saturday, July 02, 2005 3:18 AM
> Subject: RE: REFLECTOR: Painting with Awlgrip
>
>> 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?
>
> I waited about 30-45 minutes, looking for tacky feel to the paint. It was
> pretty sticky. I'm thinking I could have waited a bit longer - with your
> suggested 1.5 hours, I will certainly try that.
>
>>
>> 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.
>>
> A good friend of mine also made the comment that if the first coat of
> Awlgrip is too dry, it just causes orange peel in the following layer(s).
> Too bad you can't just apply one coat - my first coat was gorgeous!!!!
> And
> only one run on the end of an elevator where I shot the end and got too
> much
> paint on the adjacent surface.
>
>> 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.
>
> I was very surprised at how well the Awlgrip covered. I used Bondo
> surfacing putty to fill in little nicks and pinholes that the primer
> didn't
> cover. This putty is dark red. The Awlgrip covered it very nicely on the
> second coat.
>>
>> 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.
>
> I will try lowering the pressure to 6 psi.
>
>>
>> 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.
>
> As I mentioned earlier, my purpose in just painting the bottoms is to
> learn
> as I go. I will tape, mask and sand the bottom nose of the elevators
> (only
> place that there is an overlapping area) when painting the top sides.
> This
> joint will pretty much hide behind the canard. I am planning on doing the
> same for the noses of the canard and wing, with the paint joint on the
> underside of the nose. There is a lot less chance of runs if the surfaces
> are flat - hence painting the bottoms separately from the tops.
> Hopefully,
> by the time I get to the fuselage, I will have the runs under control!
> (???)
>
>> 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.
>
> Awlgrip certainly covers better than the stated 210 sq feet per gallon.
> And
> by the way, my ounces are weighed ounces (16 oz per pound) instead of
> fluid
> ounces. A gallon of mixed paint weighs 9.34 pounds or 149 oz per gallon.
> I'm using my postal scales to weigh out the exact amount of paint (color,
> converter and reducer). Oh and by the way, included in this painting
> batch
> was the bottom cowl - sorry I left that out.
>
>
>> 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.
>
> I am headed to the airport this morning and will pull the pieces out into
> the sun. Being in the dark hanger with light coming in at an angle
> parallel to the surface certainly makes things look worse (like a ceiling
> lamp shining across sheet rock - sure shows up the joints!!!)
>>
>> 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.
>>
> I am only using the standard T003 reducer and saw no solvent pops, so I'll
> stay away from the high temperature T005. Let me know how it goes with
> the
> fuselage!!! I will paint the bottom of one of my wings today if the
> humidity will get down to something closer to 50%. Forecast is 60% at 2
> pm.
> Learning as I go!!! Ain't homebuilding fun!!!
>
> At least I have enough paint per your and my calculations - less than 2.2
> gallons mixed paint for the whole 173 Elite.
>
> AGAIN, THANKS!!!!!!!!!!!!!
> Ronnie
>
>> 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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>
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