Paint for fabric covered aircraft

[chuckb01]

Hi,
My first post I think. I am in the process of building my 4th experimental aircraft and I am having a problem choosing a GOOD paint. The airplane is an older kit called a Seastar. I think there is more than one Seastar. This one is the same as the Paturi or the Petrel which is manufactured in Brazil. It is a bi-wing amphibian. The wings are fabric covered and the fuselage is fiberglass/Kevlar/carbon fiber. Other airplanes I have built I used Polyfiber or Superflight products usually. One was painted with the 2 part polyurethane polyfiber. Great finish but tons of work and all minor imperfections stand out. And one I painted with regular polyfiber and the yellow I was sold, FADED very badly after only 3 months. Really looked awful. I would rather not use a 2 part on this plane but I need something durable. I have a lot invested in this in both time and money. Time? Years actually. My problem is I want to paint it in a nice pattern using a lime green like "Go Daddy" green and yellow like DHL yellow. And white and some black. Polyfiber said they wanted about $500.00 a qt to mix the paint as I recall. Not today I think!!. So does anyone have any ideas what I can use, or maybe mix my own using polyfiber or what? I have seen some nice airplanes out there using lime green. It has to be pigment based I understand so it won't fade. I won't use latex of any type of vinyl or water based. If anyone has any ideas, i would appreciate it. This is my last build and it has to be my best, I hope. I will probably need to sell it when it's done. Thanks everyone

[Sam Buchanan]

Even though PolyFiber doesn't recommend it, many fabric aircraft have been painted with automotive polyurethane paint. The modern polys are quite flexible and the ones I've seen seem to be holding up very nicely. This will yield a high gloss finish that will hold its gloss with no upkeep other than the semi-annual wash job. Kawasaki Green should be very close to what you are looking for or one of the lime green tints from 70-ish Mopar muscle cars. Hyunda has a stunning yellow on their new Veloster cars.

[Bill Berson]

Automotive polyurethane (DuPont Imron) will last about 5-10 years outside and then get brittle and crack. Also cracks in cold weather. The old dope can last 20 years.

[Sam Buchanan]

Imron is not one of the modern automotive finishes.

How many of our custom-built planes spend their life tied down on a ramp?

[Bill Berson]

In Alaska, 95% are tied outside for life.

[Sam Buchanan]

I bet it is 100% in Siberia.....

[cub builder]

It used to be acceptable to use any polyurethane paint over polyfibre, but the STC was rewritten to require the use of their paints. It gives them better control of the finishes and limits the blame if you use something other than what was recommended.

I painted my SuperCub Clone with an automotive polyurethane paint over butyrate dope. It worked well enough, and at 7 years old, so far still looks great. Admittedly, it rarely spends a night outside, but it does see plenty of flight time. I needed to touch up some fabric damage on a gear leg and found the original paint had precipitated out a bit in the can and no longer matched, so had some acrylic urethane mixed to match. I also needed to modify an elevator, so when I recovered the elevator, I finished it with Acrylic Urethane over top of butyrate dope. The Acrylic Urethane is easier to shoot and much easier to spray a nice finish as compared to polyurethane, and so far, I am not seeing any issues with the Acrylic Urethane either. I'm thinking if I ever build another Experimental, or live long enough to need to recover the Cub Clone, I'll likely cover with Stewart's and finish it with an Acrylic Urethane. Before someone jumps on the "you can't do that" bandwagon, note that it would be an E-AB aircraft, and would definitely be an experiment; albeit based on my experiments so far, an experiment I predict to be successful.

[Kyle Boatright]

It used to be acceptable to use any polyurethane paint over polyfibre, but the STC was rewritten to require the use of their paints. It gives them better control of the finishes and limits the blame if you use something other than what was recommended.

I painted my SuperCub Clone with an automotive polyurethane paint over butyrate dope. It worked well enough, and at 7 years old, so far still looks great. Admittedly, it rarely spends a night outside, but it does see plenty of flight time. I needed to touch up some fabric damage on a gear leg and found the original paint had precipitated out a bit in the can and no longer matched, so had some acrylic urethane mixed to match. I also needed to modify an elevator, so when I recovered the elevator, I finished it with Acrylic Urethane over top of butyrate dope. The Acrylic Urethane is easier to shoot and much easier to spray a nice finish as compared to polyurethane, and so far, I am not seeing any issues with the Acrylic Urethane either. I'm thinking if I ever build another Experimental, or live long enough to need to recover the Cub Clone, I'll likely cover with Stewart's and finish it with an Acrylic Urethane. Before someone jumps on the "you can't do that" bandwagon, note that it would be an E-AB aircraft, and would definitely be an experiment; albeit based on my experiments so far, an experiment I predict to be successful.

IIRC from a factory tour some years ago, the Legend Cub guys used PPG Concept (an automotive Acrylic Urethane) as the topcoat on their factory built planes. I forget which system they used through the silver coats. Maybe Stewarts, maybe not...

[chuckb01]

Thanks very much for your reply. I have been doing some research on polyurethanes and have used them before on fiberglass sailboats and one seaplane hull. I did some more research on Imron and peoples opinion vary. Some say it will kill you. Some say you need a fresh air respirator. I used an organic respirator with no problem. And i don't paint outside because the smell of the stuff seems to attract the bugs. I may do a couple test samples of fabric i have put on test frames about a foot square. I think it will work on fabric from what I found out so far. thanks again

[chuckb01]

Automotive polyurethane (DuPont Imron) will last about 5-10 years outside and then get brittle and crack. Also cracks in cold weather. The old dope can last 20 years.

Thanks but no on the dope. I have been doing research on Imron and most agree it will work. I still need to find out more though. I really don't want the wet glossy look and i think Imron comes also in a semi gloss.