Stewart System Paint

[ak49flyer]

Interesting- I don’t think that info was in the manual when I was using the system 6-8 years ago. Haven’t ever heard of sealing with Ekopoly from the outside; would make me nervous about the ekofill adhesion. So I guess you’d seal the areas aft of the tank bay from the outside, and paint the inside when doing the topcoat…? (I agree it’s easy to do and takes no time, just had issues with the unprotected areas aft). Probably best to do the left side of fuselage and belly areas too, since those can get pretty saturated if a plane sits for a few days with an undetected leak…

 

[EdH]

Does anything say don’t use autogas or it could ruin the coating? Seems like this is a huge problem, especially since so many cubs and older planes use it these days.

Sent from my iPhone using SuperCub.Org

 

[jimboflying]

Which layer of the Stewarts system is being affected by the Mogas?

 

[Rob]

Interesting- I don’t think that info was in the manual when I was using the system 6-8 years ago. Haven’t ever heard of sealing with Ekopoly from the outside; would make me nervous about the ekofill adhesion. So I guess you’d seal the areas aft of the tank bay from the outside, and paint the inside when doing the topcoat…? (I agree it’s easy to do and takes no time, just had issues with the unprotected areas aft). Probably best to do the left side of fuselage and belly areas too, since those can get pretty saturated if a plane sits for a few days with an undetected leak…

I never read this either, but it makes total sense to me. As for adhesion, I can't imagine any problem, after all you already have the same products layering in the standard application, they are just in opposite sequence.
Agreed on the left fuselage, that is the only place I've ever had a problem on the 15 y/o finish on my cub. Leaky fuel selector. Peeled at the lower longeron, but I was far more disappointed with the fuel selector r&r than I was with the SS product.
As for vents and drains, I think they're a huge help. I feel like total saturation followed by a quick flash off is far less damaging than a chronic seep. My tank covers do not have the rubber doughnut, and my middle name is not Grace. I have spilled far more fuel in to my wings than I can remember, and have watched it rain out the back, but it's always dry a few minutes later and have yet to have a blister under the wings. Conversely, on the left fuselage I would have never know there was a leak if the paint didn't blister and peel, yet when I removed the inside panels the inside of the fabric was heavily stained blue. My fuel is typically loaded Rt tank Mo, and Lt tank Av.

All systems have a compromise, you just need to pick which compromise effects you the least and which positive attributes are most desirable to you.
I've been impressed with SS so far. So much so that last year I did a set of AG Cat feathers, as well as the tail of one of my Thrush' That airplane now has two corn run seasons on it and one fall through spring produce season on it. For comparison, prior to this, it was going through legacy systems to the tune of a new cover job every year. I know of no harsher life on a fabric system than this;

A) Caustic chemical baths on every flight
B) Pressure washing to remove said chemicals, and lastly
C) 24/7 outdoor storage in one of the hottest desert climates in the nation.

Take care, Rob

 

[Marty57]

Does anything say don’t use autogas or it could ruin the coating? Seems like this is a huge problem, especially since so many cubs and older planes use it these days.

Sent from my iPhone using SuperCub.Org

We address the issue of autogas in the same section as I indicated. The issue with autogas is often a regional issues. I have another fabric sample that I tested the same time, and from the same fabric swatch, as the sample in 100LL. It was first tested in autogas w/ethanol in Ohio and there was no issue with the sample. I placed a piece in CA 10% Ethanol fuel and the paint separated from the fabric in the matter of minutes. This is consistent with other issues I have had with autogas here in small engines; it destroys many carb parts if left in the engine for any length of time. I have no idea what is in CA fuel but it is pretty bad compared to other regions. Auto Gas, without ethanol, should be ok but it depends on the region. Auto gas today just doesn't have any national standards so it is impossible to have any fabric system resistant to all auto fuels across the country. In the case of the sample I tested, the top coat was unaffected by the ethanol based fuel; it was the bond between the fabric and the Ekofill where we fill the weave with EkoBond glue. Painting the inside of the fueltank bay, having adequate drain holes and grommets, and sealing fabric as we have outlined in our manual will prevent this debonding from additives that may be found in auto gas. When I teach fabric covering, I recommend making a couple 2' x 2' wood frames and covering them with fabric through the entire system, including top coat. You will not only learn how the paint behaves as you shoot it but you will have fabric painted that can be used for patching a damaged area. Relevant to this post, you will have fabric to test in your regional auto gas if you desire. In CA we have totally different auto gas in summer vs winter. We have no ethanol free auto gas available so it is a moot point for most aviation use but in other regions, I would want to know how my fabric reacts to auto gas; regardless of the system used. As a homebuilder, I trust the Stewart Systems but I am very leary of the auto gas available here in CA.

Marty57

 

[bob turner]

It used to have MEK in it. MTBE? It does eat stuff - the rubber hoses on my ‘65 Mustangs needs replacement at ten year intervals. Doesn’t seem to affect auto carbs (or indeed Strombergs).

 

[bcone1381]

I've thrown out Stewarts paint because I mix too much up. I've run out half way through spraying my final wet coat because I didn't mix up enough.

I'm now documenting how much I use (measured in Grams) per sq ft. I'm painting Insignia White paint over Smoke Gray primer. In my next session I will mix up 14g of part A per sqft. with a goal of mixing up 10 - 15% left when I am done with my final wet coat.

But my Question is, does anyone out there have a formula they use?

Question 2, maybe a formula exists that I will use a certain percentage (like 100%) painting the wet coat as I did spraying four fog coats (= two cross coats)

 

[Marty57]

I've thrown out Stewarts paint because I mix too much up. I've run out half way through spraying my final wet coat because I didn't mix up enough.

I'm now documenting how much I use (measured in Grams) per sq ft. I'm painting Insignia White paint over Smoke Gray primer. In my next session I will mix up 14g of part A per sqft. with a goal of mixing up 10 - 15% left when I am done with my final wet coat.

But my Question is, does anyone out there have a formula they use?

Question 2, maybe a formula exists that I will use a certain percentage (like 100%) painting the wet coat as I did spraying four fog coats (= two cross coats)

These are really good questions and it comes up when I teach painting. Your 14g /sq ft is pretty close but it will depend on the person behind the gun. Another formula that works well is the amount of paint needed for the three fog coats will be roughly the same amount of paint needed for the wet coat. When starting a paint job, mix up a batch of 200 g of paint (200g paint + 50g catalyst +50g water). I don't add all the water; only about 75% then check for viscosity of about 26 seconds with our metal viscosity cup (every cup is different by the way). Add additional water as necessary to reach 26 seconds. See how far that goes with your application process for fog coats. It's easy to mix another small batche to get to that full color saturation at three fog coats. If it turns out it took you 400g (I keep track based on raw paint for my calculations) for the fog coats for that shoot than I mix 800g for my wet coat. That should give you a reasonable amount.

On the Waco I shot, I used 600g for the fog coats on one wing, and 1100 on the wet coat. Total was 1700g. The wing is about 150 sq ft so based on 14sq ft/g you would use 2100g.

My recommendation would be to initially mix about 11g/sq.ft. (plus cat and water) and shoot a given part (two horizontal stabs for instance). It's easy to figure the size of those parts to determine paint mix. Shoot the fog coats and see how that ratio worked. If you had an acceptable amount than double that for the wet coat and you should be about right.

I attached a picture of what the fog coats should look like. The lighter the better for that first fog coat. It's ok to do four fog coats but just 2 fog coats to get to color saturation is too heavy and will result in orange peel.

Marty57

 

[bcone1381]

Another formula that works well is the amount of paint needed for the three fog coats will be roughly the same amount of paint needed for the wet coat.

When starting a paint job, mix up a batch of 200 g of paint...... See how far that goes with your application process for fog coats. If it turns out it took you 400g (I keep track based on raw paint for my calculations) for the fog coats for that shoot than I mix 800g for my wet coat. That should give you a reasonable amount.

On the Waco I shot, I used 600g for the fog coats on one wing, and 1100 on the wet coat. Total was 1700g. The wing is about 150 sq ft so based on 14sq ft/g you would use 2100g.

...Shoot the fog coats and see how that ratio worked. If you had an acceptable amount than double that for the wet coat and you should be about right.

Thanks Marty!!

Clarify that Wet Coat will consume two times (or 1X?) the grams of part A consumed to shoot 3 to 4 Fog Cross Coats.

Definitions & nomenclature: Fog Coat, Cross Coat..... I spray one fog coat left to right. I wait until it tacks up. Then I spray the next fog coat up and down. Those two fog coats equal one cross coat. I'll call it a Fog Cross Coat.

I've been spraying 2 Fog Cross Coats. I'll be doing 3 or 4 Fog Cross Coats from now on. I have some minor color variation going on......its not bad enough for wife to name the aircraft "Patches" but I can see it. That might be part of my issue.

Everyone out there, what Marty says about viscosity is critical. We use a Ford #4 cup and I target 23 seconds when I shoot with my small deVilbiss SriPro gun, and 26 seconds when I spray with my big Pro-Tek gun. 28 seconds gives bad orange peel, 27 second slight orange peel, 26 is sweet, 25 seconds is sweet on a flat surface and turns out real nice. I'm scared of runs so a vertical surface at that viscosity is risky. I mix it my paint and keep track of the water I add to get that viscosity. I'm finding 60-70% water is good for my big gun. 90% for my small gun.

 

[Dan Gervae]

I get other project parts ready for top coat when I start painting..if I have paint left when I’m done….instead of tossing it..I paint another part of the project. Gun: Devilbiss finish line ….pressure 70 no trigger pull, 23 psi with trigger pull. Awesome finish. 3 fog cross coats. I’m better this project than last one
.

 

[RedOwlAirfield]

I'd still like to see someone use house paint and a 6 inch brush just like they did in the 30's at Lockhaven! Talk about original! I was fortunate enough to have had a good friend that began instructing back in the 1930's and he told me new cubs looked terrible.

Seriously though I do appreciate y'all going to such extremes for paint, but I have to admit I find it a bit silly. Airplane doesn't fly one whit better. I think we'd all do better to recall that sometimes less is more.

(Donning my asbestos underdrawers...)

 

[skywagon8a]

I'd still like to see someone use house paint and a 6 inch brush just like they did in the 30's at Lockhaven! Talk about original! I was fortunate enough to have had a good friend that began instructing back in the 1930's and he told me new cubs looked terrible.

Seriously though I do appreciate y'all going to such extremes for paint, but I have to admit I find it a bit silly. Airplane doesn't fly one whit better. I think we'd all do better to recall that sometimes less is more.

(Donning my asbestos underdrawers...)

Here you go. The color doesn't match because I screwed up and used the wrong chip when the paint was mixed. This is house paint over the Stewarts system through primer. The straight section is aluminum and the tapered section is covered with fabric. No issues.

 

[Dan Gervae]

I struggled with the paint the first time….I followed the directions, but chose to mix by volume rather than weight…no comparison. The gun and settings are important and you must have a big compressor. The tack costs are the most important ….after that the stuff behaves very well….needs to br around 70 degrees though…with regard to old school paint..I have no problem with not shiny paint but I’m doing this Cub for a customer who wants a shiny Cub…it’s expensive to restore a Cub so why not make it look good if you can…it costs the same to make it that way I guess.

 

[Marty57]

Thanks Marty!!

Clarify that Wet Coat will consume two times (or 1X?) the grams of part A consumed to shoot 3 to 4 Fog Cross Coats.

It's double the amount of the fog coats when you mix for wet coat. If you mixed 300g of paint (plus catalyst plus water) for a set of flaps and ailerons than you would need to mix 600g of paint (plus catalyst plus water) for the wet coat for those parts. You will likely end up with maybe 10% left over when finished but I hate to run out paint before I finish that wet coat. The trick is to just keep track of what you use for your fog coats as you go along. If you need another 200g to finish the fog coats on a big job like a fuselage,(all 3 fog coats, up to color saturation) then just add that to your tally. Double that amount and you should be good. I always keep track of my mix based on the raw paint so I don't get confused. Different pigments will need different amounts of water (remember, use distilled or reverse osmosis water) to hit 26 seconds.

Marty57

 

[Marty57]

I get other project parts ready for top coat when I start painting..if I have paint left when I’m done….instead of tossing it..I paint another part of the project. Gun: Devilbiss finish line ….pressure 70 no trigger pull, 23 psi with trigger pull. Awesome finish. 3 fog cross coats. I’m better this project than last one.

Dan,
That's a great idea. If you have other parts ready, use the extra paint even if you only get one or two fog coat on the next part. Come back 24 hours later, go over it with scotch brite or 320 open coat to scuff the surface than blow and wipe, clean and you are ready to shoot. If you got all three fog coats done with the extra paint, after doing the above steps you will shoot one very light fog coat to get the surface tacky (I refer to it as a tack coat) then on to my wet coat. At $400 or so per gallon anything you can do to keep from throwing away paint is a great plan.
Marty57

 

[Marty57]

I'd still like to see someone use house paint and a 6 inch brush just like they did in the 30's at Lockhaven! Talk about original! I was fortunate enough to have had a good friend that began instructing back in the 1930's and he told me new cubs looked terrible.

Seriously though I do appreciate y'all going to such extremes for paint, but I have to admit I find it a bit silly. Airplane doesn't fly one whit better. I think we'd all do better to recall that sometimes less is more.

(Donning my asbestos underdrawers...)

I've done some repairs with our system in a hangar that we could not spray in. I rolled and tipped the paint. Here's a link to directions on our website on how to roll EkoPoly Premium. It actually came out pretty good. I block sanded it a little and than buffed it some and it looked ok. There's a nice Citabria up in Talkeetna done mostly in black to help with snow melt; all done with a roller and brush.
Marty57
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://stewartsystems.aero/wp-content/uploads/EPP-Rolling-Directions.pdf

 

[Sarpy]

I've done some repairs with our system in a hangar that we could not spray in. I rolled and tipped the paint. Here's a link to directions on our website on how to roll EkoPoly Premium. It actually came out pretty good. I block sanded it a little and than buffed it some and it looked ok. There's a nice Citabria up in Talkeetna done mostly in black to help with snow melt; all done with a roller and brush.
Marty57
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://stewartsystems.aero/wp-content/uploads/EPP-Rolling-Directions.pdf

Was laying down the wet coat today and a wasp landed and tracked through it. How long need I wait before buffing and is there any guidance for buffing Stewart’s topcoat?

Sarpy Sam

 

[Marty57]

Was laying down the wet coat today and a wasp landed and tracked through it. How long need I wait before buffing and is there any guidance for buffing Stewart’s topcoat?

Sarpy Sam

I would wait a couple days to give the topcoat time to cure. You can then wet sand; work up to 1200 or 1500 grit sandpaper. Don't be aggressive around tapes, stitches or rivets to avoid cutting through a high spot. I use MeGuiars diamond cut for buffing the sanded area back to a shine.
Marty57

 

[Marty57]

I did a covering and painting seminar over the weekend; had a group from Alaska down here. The results were really nice; top left panel was done start to finish by a 12 year old girl. I've realized how difficult it is to explain just how light the first fog coat needs to be with Stewarts Systems so I shot this panel yesterday to better show the relationship of the fog coats to the wet coat. The wet coat on this 4 part panel is one pass, left to right with the panel horizontal on a stand.

Marty57

 

[Hardtailjohn]

Was laying down the wet coat today and a wasp landed and tracked through it. How long need I wait before buffing and is there any guidance for buffing Stewart’s topcoat?

Sarpy Sam

I did a video on it a while back.... you can do as good or not good as you want....

https://youtu.be/DPULa4Eebz0?si=-0EFbKlQ2oGw5TMm

 

[Dan Gervae]

the last part I paint will be the nicest part on this plane. Practice makes perfect. Lol

 

[jimboflying]

Since winter is approaching, which components are freeze sensitive for shipping?

 

[phdigger123]

Stewart does a nice job of packing their shipments for cold weather. They put in heat packs and freeze sensors. I have had no problem. Stewarts watches the weather and won’t ship if the cold is extreme.

 

[Marty57]

Since winter is approaching, which components are freeze sensitive for shipping?

Primers, EkoFill and EkoBond are sent in heat pack insulated boxes as they are freeze sensitive. EkoCrylic and EkoPoly Premium are not freeze sensitive so no issues there.
Marty57

 

[PA18project]

I thought I would give a plug for the Stewarts system that I havent seen before.
Recently someone was painting some wings and got a bunch of overspray on my plane. Basically, the hanger door was open while someone was spraying outside and my plane got covered. I called Stewarts and explained the situation. They recommended that I try wiping the overspray off with MEK (not the plexi of course). I was suspect because MEK is terrible stuff but I tested a small area and sure enough, it took the overspray off without damaging the paint and without dulling the finish.
I just finished wiping most of the overspray off today and couldnt be happier. The paint job is probably 7 years old at this point and it is holding up well and looks great. The fact that I was able to take off the overspray was a huge bonus.
I remain very happy with the entire stewarts system and will happily cover my next plane with their system.

 

[Marty57]

I thought I would give a plug for the Stewarts system that I havent seen before.
Recently someone was painting some wings and got a bunch of overspray on my plane. Basically, the hanger door was open while someone was spraying outside and my plane got covered. I called Stewarts and explained the situation. They recommended that I try wiping the overspray off with MEK (not the plexi of course). I was suspect because MEK is terrible stuff but I tested a small area and sure enough, it took the overspray off without damaging the paint and without dulling the finish.
I just finished wiping most of the overspray off today and couldnt be happier. The paint job is probably 7 years old at this point and it is holding up well and looks great. The fact that I was able to take off the overspray was a huge bonus.
I remain very happy with the entire stewarts system and will happily cover my next plane with their system.

Glad to hear how well it worked out. It’s a tough paint indeed.
Marty57

 

[Dan Gervae]

I thought I would give a plug for the Stewarts system that I havent seen before.
Recently someone was painting some wings and got a bunch of overspray on my plane. Basically, the hanger door was open while someone was spraying outside and my plane got covered. I called Stewarts and explained the situation. They recommended that I try wiping the overspray off with MEK (not the plexi of course). I was suspect because MEK is terrible stuff but I tested a small area and sure enough, it took the overspray off without damaging the paint and without dulling the finish.
I just finished wiping most of the overspray off today and couldnt be happier. The paint job is probably 7 years old at this point and it is holding up well and looks great. The fact that I was able to take off the overspray was a huge bonus.
I remain very happy with the entire stewarts system and will happily cover my next plane with their system.

Did you use the MEK replacement or the old stuff?

 

[PA18project]

Good question. I used the real thing. That is what they recommended and so that is what I used. I tested a few hidden areas first and candidly, I expected it would lift or dull the paint. MEK is pretty awful stuff so gloves and a respirator are required. Hopefully I am the only guy that has to do this.

 

[Steve Pierce]

Stewart paint is like any other catalyzed polyurethane, the difference is it is carried via water instead of a solvent. I learned this from Dan Stewart many years ago. Most any catalyzed polyurethane (Aerothane, Ranthane, AirTec) I have worked with is impervious to MEK. However, test like posted above in an inconspicuous spot.

 

[Pershing]

Recommend you get in touch with Steve Pierce. He has quite a bit of experience with Stewarts. Apparently the application technique is different from spraying poly or dope, but if done properly, is as good as other systems and without the chemicals.

Can I get contact info for Steve Pierce I need someone to paint my Stewart’s system