Stewart System

[Jim Herpst]

Ok another covering system question of the day. After reading on the internet about some issues with Stewarts I have come to a conclusion that it appears to be very tricky to lay the paint down with out entrapment under the paint...BUT is solvable by following the directions to a T.

So stated what have others (who used the product please) have to say and perhaps show and tell. I do not see anywhere near the volume of "misfires" with other systems. That said the water born idea is something holding intrigue for obvious health and clean up reasons.

[Guest]

I used Stewarts and loved it until some fuel leaked and half of the left side of the fuselage was really messed up.

They say it's fuel proof, be careful.

[skip]

I rebuilt my wings in 2014 with Stewarts. I painted in early spring with the hanger about 60 degrees and more important I think at 7200 MSL. Low vapor pressure at that altitude you see. The fill coats are a breeze even using a cheap Harbor Freight gun. And it is wonderful to not have to wear a moon suit to avoid MEK fumes.
The final finish coat (eco-poly, Insignia White) was more trouble. I have a good DeVilbis s gun and the finish paint really wants a good gun. My tests following their instructions resulted in lots of orange peel. I think the high altitude and minimum temperature were both a big factor. Thinning a bit to a few seconds less from the viscosity cup, adjustment to the gun for a bit finer sprey, and four instead of three coats made a big difference. My wings have a little orange peel looking closely, but no more than I see on other paint jobs.
Since then I have done some smaller jobs with both eco-poly and eco-cryllic on metal and the bit thinner paint for the altitude with more normal temperatures have resulted in good shiny paint. I do think that eco-cryllic in particular is a bit more fussy than other finish coats.

Dave, My wings have wing tanks. I am not the most careful line boy and tend to run 100LL down the wing each time I fill and the paint has held up just fine. I wonder what's going on with yours?

All in all I am happy with the Stewarts system stuff.

Skip Egdorf
N34237

[Guest]

Skip I do not know why. I did strip it off and repair, looks poor, but I do know this for sure- it is not fuel proof.

One could say its all my fault for have a loose fitting that weeped, but it is not fuel proof.

I am careful not to spill and I clean off what spills when I do.

I would probably use it again.

[skip]

I used Stewarts and loved it until some fuel leaked and half of the left side of the fuselage was really messed up.

They say it's fuel proof, be careful.

Dave,
Looking at you pictures it looks like the fuel went down the inside and attacked the paint from underneath. So my experience running fuel over the outer paint coat shows that it is indeed fuel proof from the outer surface. However getting fuel inside and underneath lifts it! That is really good information.
I notice that Stewarts changed their STC instructions last year to have you do an initial fill coat of their glue before the eco-fill spray. I was puzzled by that as the eco-fill seemed to fill the weave just fine. I wonder if addition internal fuel proofing was a part of their consideration and they just changed the instructions without telling us why?
Thanks for posting the pictures!

Skip Egdorf
N34237

[Guest]

Dave,
Looking at you pictures it looks like the fuel went down the inside and attacked the paint from underneath. So my experience running fuel over the outer paint coat shows that it is indeed fuel proof from the outer surface. However getting fuel inside and underneath lifts it! That is really good information.
I notice that Stewarts changed their STC instructions last year to have you do an initial fill coat of their glue before the eco-fill spray. I was puzzled by that as the eco-fill seemed to fill the weave just fine. I wonder if addition internal fuel proofing was a part of their consideration and they just changed the instructions without telling us why?
Thanks for posting the pictures!

Skip Egdorf
N34237

Darn! If I had known that I would have put the leak on the outside! LOL :-)

Dave

[N96337]

SOME auto gas will lift it, like Dave found out. Most wont. Andy has samples that have been submerged in 100LL as well as auto gas for over a year and they're fine...other samples from other sources of car gas lift quickly. All that being said, I have seen the other systems have problems with certain fuels too. The manual has been changed to caution people to not use autogas to initially test the system.
The filling the weave with the Ekobond was the way it was done originally, back when I was part owner of the system. We didn't like to fill with Ekofill because there was a higher chance of moisture entrapment and blistering if the conditions are right. When Stewarts bought the system, they changed the procedure to an initial fill coat with Ekofill over moist fabric. The other problem came from people not quite understanding the procedure and wetting a whole wing, then brushing fill in. Often, by the time they got to the end of the wing, the moisture had escaped the fabric and they wound up with an adhesion issue. So, as you said, Andy took the procedure back to what it was in the 90's.
If you're going to be using auto fuel, they recommend a brush coat of EkoPoly Premium, on the bare fabric in the tank area, then apply the seal and fill coats as usual.
As far as the solvent pops in the paint.... you have to remember that you're evaporating water as your solvent, not a chemical with a higher flash point, so it takes time. The "minutes" suggested are NOT set in stone as far as time between coats are concerned. What you're looking for, is a tacky surface, with NO paint transfer to your finger when you touch it. That holds true for pretty much any polyurethane paint, but especially true for a waterborne. Most people rush that step and wind up with a solvent pop. Airflow across the surface, humidity, temperature and especially coat thickness change the "time to ready" greatly. In the winter time, I've gone home and eaten supper right after applying a coat, and been back in time to apply the final coat. Drying on this paint is very different from a solvent borne paint. What you have in the paint booth today is not necessarily what you're going to see in a month. This stuff flows out for a long long time!! When I was painting with solvent borne paints, we'd shut the fans off and the heat off, just as soon as we got the last coat on, and slow the drying process to achieve a better gloss. The Ekopoly Premium loves heat. When I'm done on the last coat, I leave the booth fans running and go clean everything up, then come back and shut it down but put a couple unit heaters in the booth and crank them up hot! When I teach the paint class at Sun N Fun, the paint booth we use is like an oven, and this paint loves it! I agree that it likes 4 coats usually, but the absolutely best finish I ever had with it was with a fog and 2 medium coats. I shoot a Devilbiss Tekna Pro Lite, and it's ok. I've shot it with the Devilbiss Finishline FLG4 that is recommended, and to be truthful, it does as good a job as the Tekna ProLite for a lot less money. I used to shoot a Walcom Geo and it did a beautiful job, but I can't find an adapter for my DeKups system, so I don't use it much anymore.

[Jim Herpst]

This has been very helpful. Thank you to all the participants !

[astjp2]

It’s a mediocre system at best, anything good has real solvents in it. All of the painters I have talked to about water born paints hate them and are very vocal about their opinions. Stewart's blushes bad in the rain, and is not really fuel proof. I am sticking with stitts until I cannot buy it anymore because the libs will try to outlaw it for whatever reason of the month. Tim

[N96337]

I've NEVER seen it blush from rain....and I've been using it since the 90's. It's more flexible than anything out there. I know people hate to change, and that's why a lot of painters don't like it and screw it up. They can't wrap their head around the differences. It IS different, not difficult.

[astjp2]

I've NEVER seen it blush from rain....and I've been using it since the 90's. It's more flexible than anything out there. I know people hate to change, and that's why a lot of painters don't like it and screw it up. They can't wrap their head around the differences. It IS different, not difficult.

I have a few friends up in Alaska that were really hot on using it on customers airplanes, after a while, they started to get a few complaints and now they are back to stits because of not wanting warranty issues...but some cub guys are real anal.

[N96337]

There were some issues with adhesion on the fill coat, when Stewarts started using the fill coat to seal, like I was describing above. It also wont tolerate freezing before it's applied. It is different!! I had a time with it when we were starting to get it refined, but once I got ahold of the right guy that got my mind wrapped around the waterborne aspect, it makes sense and works great. It'll never work like a solvent borne, but it wont harm you like one either. I had 2 choices... quit covering/painting completely, or find something else that wasn't solvent borne and didn't have the free radicals as bad. This system worked for me. The more I use it, the more I see the ease of using it. Like I said, not tough, just different.

[at7615]

I've NEVER seen it blush from rain....and I've been using it since the 90's. It's more flexible than anything out there. I know people hate to change, and that's why a lot of painters don't like it and screw it up. They can't wrap their head around the differences. It IS different, not difficult.

I'm using waterborne exclusively! Easier, safer, cleanups a breeze!

[at7615]

Andy told me wax it with carnuba 30 days after spraying, should help with fuel and washing the aircraft.

[1938BF50]

From a user perspective, the Stewart System is fantastic and hands down, the BEST system available. I wish the lingering animosity towards the name would go away. I have two sets of new Airframes Alaska PA-18 control surfaces covered thru EcoFill (silver) sitting in AK that most shops wont even look at when I mention Stewart Systems.