Painting with Stewarts System

[jmodguy]

single stage polyurethane

[Flybyjim]

I have to agree with the earlier post, painting is 95% prep work. I have sprayed 5 planes with either poly tone, super flight, and PPG paints. A friend asked if I would spray his wing after a repair and I agreed to do the job using his Stewart paint.

I called and talked to the Stewart folks in Ohio about the process. I came away with a concern and that was the amount of CFM's required to flow their paint, pressure is always available but not enough CFM's and the paint will not atomize properly.

So I used a smaller HVLP Sata 4400 mini gun that requires only 6CFM as compared to a Devilbiss finish line at 13 CFM. It was odd spraying at such a fast movement of the gun to keep the paint as a fog coat but with a practice panel I got the hang of it with just a couple passes. Now when I spray with most paints I have the fan wide open and the flow control also very open and control the amount of paint applied to the surface by distance and speed. I was amazed at how long it took the fog coats to set up and be ready for the next fog coat, 10-15min on the first fog coat, 20-25 on the next fog coat. For the final coat, you need to move in a bit closer with the gun and slow the pass down just a bit to get a good finish. As you spray this last coat the paint needs go wet behind the gun speed by about 5 seconds. If you spray a full wet coat it will run or set up with pin holes from gasing out.

For my own Kitfox I am going with the Super flight system with PPG paint. I know this system best and have always gotten great results.

Just my experiences to share with you, all systems seem to work for some and not others.

Jim

[N14ND]

I am "super" anal. I made sure that I was able to check off all of the Stewarts boxes on gun, air supply, CFM, prep, paint gun, tip size, you name it. The Battleship Gray that is the base coat went on nicely. I also did a few test panels first, then did a bunch of small parts before painting the fuselage. Aluminum panels, the composite doors and they all came out fine.

The Midnight Black has been nothing but trouble. I have wondered if it is a problem with the color dyes, as the base material is the same batch as what went into the gray. I don't know. They don't think so. It is still operator error to them. The fog coat recommendation is to color saturation, so it took 3 light fog coats of black to cover the gray, each one I waited for tack to no transfer. Then lay on the final coat that I made sure that I did not apply too thick. It looked great at 2 hours...mirror finish. I was stoked. Then the next day.....ugh.

No silicone or oil, anywhere. I have Stewarts tack rags and wipes and prep and clean, mix and stir exactly as they request. Everytime I pull the trigger on the gun with Stewarts I have trepidation. I have spent way too much time building this to have my paint look like a POS.

As this is an experimental I don't care about using the Stewarts System to compleation. So I have a test kit coming from Airtech Coatings to see if their single-stage solvent based polyurethane paint is compatible with the Stewarts Ecopoly to go over the top. They are not sure if there will be a reaction. They think if the Ecopoly Premium is a true polyurethane that their paint should be able to adhear and not cause any issues. I will be the test. I am going to apply some of their paint over some off my SS finished small parts. If that goes well, I will mask off a small area on the bottom of the fuselage and try it there.

[Flybyjim]

Well 14ND it sounds like you did all as required, sorry I can not help, I know the frustration and feel for you.

Jim

[bbs428]

I can completely empathize with your situation. I hope it turns out fantastic the second time around!

As a mechanic 1st and as a painter a distant third or fourth, I get a bit nervous every time I pick up the paint gun. I have been defeated numerous times by contamination, dust, humidity and my own stupidity! lol.

For me a single stage auto urethane with a flex agent works very well. Nice gloss, durable, huge choice of colors, easy to shoot and affordable.

A great resource is a friend who owns an auto paint store close by. Mine has educated me despite my lack of artistry. My painting projects are turning out a lot better.

All the best.

[Danzer1]

TCPGlobal has single stage acrylic urethane in quart and gallon kits. I believe this is where some of the other resellers get theirs. Can't beat their prices (generally). Go here:

YMMV, Greg

[N14ND]

It has been awhile since my last post. Been waiting for the temperature to get warmer. I don’t want to trash Stewart’s System as I really like their stuff. I just didn’t have much luck with the trim paint over the base EPP. I still think it’s a bad batch of paint. Quick recap:

1. Had millions of “solvent pops” in the SS EPP black (second color trim) paint. Shout out to Airtech Coatings as they sent me a quart of their urethane top coat and suggestions to fill the majority of holes. Any top coat system can be applied over the catalyzed Stewart’s System.
2. Sanded with 320 to expose holes (ugh)
3. Airtech urethane is pretty thin so I used my finger as a squeegee and filled as many as I could see.
4. Sanded again. Sprayed a layer of Airtech (thinned) over the top. It looked acceptable so I stopped the process trill spring.
5. An IA friend that uses SS for certified recovers said he uses SS up one coat of their cheapest top coat in white. Then paints the final color coats with Stits Aerorhane. So that’s what I did.
6. Applied their black over the repaired areas and new masked trim areas. It turned out great!

I used Aerothane as it was available locally and was 2/3rds the price of other urethanes for fabric. It was super easy to spray. Flowed nicely and has incredible gloss. I pulled the tapes off an hour after the last coat and checked it this morning, no pin holes!!! The only difficulty I had was getting used to the fresh air hood as it took awhile to get used to seeing my reflection on the inside of the visor.

[Rodney]

Agree that you have been more than meticulous. It really is a shame that a $400 per gallon paint is not working. With all the prep work you did and your set up, if it's operator error then we are all probably sunk.

FYI. This may not be of any value to you, but if it ever quits raining here in Oklahoma, I'm trying to get a 95 Dodge Pickup primed and painted.

In searching for paints, everything I was finding was in the $400/gallon range - especially for red colors. Then a friend recommended I look at Summit racing. They have a single stage Acrylic Urethane paint system, and the prices are very reasonable. For Gloss Black, you get a gallon of paint, activator and reducer in a kit for $118.00 And, it shoots very well; just like you would expect. Do NOT tell Summit that the paint goes on an airplane - if you do, I have been advised they won't sell you anything. Had a friend that was buying an oil pressure gage for his Corvair conversion and he told them it was going in an airplane and they would not sell the gage to him.

Really hope you get a paint that works and can get on with your project.
Painting is hard enough with having to deal with the problems you have encountered.

Regards
Rodney

[jmodguy]

Eastwood.com also has single stage urethanes. Don’t know how flexible they are but lot of colors!
For what its worth PPG Delta ( Delfleet?) is what some certified tube n fabric teams are using.

[jiott]

The guy that painted my plane did it full time for a living, working for a company that restores Stearmans. They exclusively use the PolyFiber system and use Aerothane for the final color coats. He told me that when you are all done, you should still be able to barely see the weave of the fabric thru the paint; if you can't, then you put on more than necessary. Two color coats is generally enough. I'm just passing this on from a professional since I know nothing about it myself.