Stewart System Paint

[mike mcs repair]

.... the people who caused the topcoat to be included with the approvals system was Polyfiber, and he had words to the effect that Polyfiber had stirred it all up. ...
Cheers,
Andrew.

that also was my understanding, (and with no knowledge of stewarts or so....) they(stitts) just complicated our lives to try to sell more of their stitts stuff and such...

[jgerard]

Bob, I'll happily sell you a 4,8,16 oz bottle of glue all ya got to do is ask The primers and paints do have a 1 year shelf life and we try very hard to only sell customers enough to do the job they are working on. I can sell you half pints or pints of EkoFill and EkoPrime if you like. Min order on paint is 1 pint. Any smaller and it's hard to control color matching. We also recommend not buying any paint until you are ready to paint the entire aircraft.

Regarding shelf life all products are warrantied 1 year unopened. It's just the way things are and has to do with chemistry not marketing. I would much rather have to send a customer an extra 16 oz to finish a job than leave them with half a gallon of unused product. With no heavy volatile solvents you don't get the same 2-3 year shelf life or the seemingly unlimited shelf life like dope. When solids fall out of solution it's much harder to get them to stir back in. The catalyst for the paint actually has a shorter shelf life than the paint it's self. I am always looking at ways to improve shelf life. If you have 1 1/2 - 2 year old EkoFill or EkoPrime it's not going to be any good. Don't buy a quart or gallon instead buy a pint at a time if all you do is small repairs with it. The glue however will last years unless it's frozen. I have used 6 year old glue that looked the same as brand new glue. Same for the EkoClean and EkoEtch.

FYI the current Stewart Systems product line has nothing in common with the old blue river process. The STC paper trail of blue river to Aircraft finishing systems was only a paper trail, The chemistry of the primers and paints didn't follow. The current chemistry is nothing like Blue river or the early Aircraft finishing system products. And the Stewart Systems STC is a stand alone STC based on new chemistry and it's the only FAR part 23 tested and certified covering system. It's not a modification of the old BR paperwork which was piggybacked onto the Ceconite STC as the 7600 process. SS has nothing in common with BR other than the concept of water born coatings.

The new EkoPoly Premium paint has really made a huge improvement in ease of application and almost completely eliminated the problems people had shooting the earlier version. (nothing is fool proof) It's 10 times more forgiving and user friendly and it shoots more like most polyurethane paints and the performance of the coating has far exceeded our expectations. The more we use it and the more feed back we get from customers the more versatile we are finding it to be.

Osmotic blistering comes from contaminates underneath or between layers of the coating affecting adhesion and acting like a "sponge" which attracts water molecules causing a hydraulic blistering of the paint. The causes of contamination are typically prep or application related. If you google osmotic blisters you'll get a ton of info on what can cause them. Vigorous testing with the latest formulas shows no signs of blistering under extreme conditions.


Jason

[kiwicubber]

Hi Jason, we had a problem with our Stewart Systems paint job. Have painted all the coats on all surfaces and are really pleased with the results. We are just in the process of reassembling the aircraft for flight, and managed to spill some brake fluid out of the master cylinder onto the belly fabric, naturally on the inside. This caused an effect similar to the application of paint stripper on the top coat. We also managed to spill some contact adhesive on the inside of the Belly with a similar result.
Can you advise what treatment we should use in both cases before we repair the paint.

[On Patrol]

Hi Jason, we had a problem with our Stewart Systems paint job. Have painted all the coats on all surfaces and are really pleased with the results. We are just in the process of reassembling the aircraft for flight, and managed to spill some brake fluid out of the master cylinder onto the belly fabric, naturally on the inside. This caused an effect similar to the application of paint stripper on the top coat. We also managed to spill some contact adhesive on the inside of the Belly with a similar result.
Can you advise what treatment we should use in both cases before we repair the paint.

You may want to send an e mail Stewarts direct as Jason is no longer with them.

[Yarddart]

My 2220 has Stewart system 20+ years looks like new just a few cracks I think it's acrylic enamel finish with flex additive so it must be a modified finish

[Iflylower]

I just heard from another that Stewart systems is in the process of moving to Ohio from Washington State this week. That makes me wonder if they've been acquired or sold.

i used Stewart's on my aircraft also. I'll wait to see if anyone else has repair advice or you.

[behindpropellers]

I just heard from another that Stewart systems is in the process of moving to Ohio from Washington State this week. That makes me wonder if they've been acquired or sold.

i used Stewart's on my aircraft also. I'll wait to see if anyone else has repair advice or you.

Cal,

Do you know where in Ohio?

[skywagon8a]

Cal,

Do you know where in Ohio?

http://www.stewartsystems.aero/news/...o-central-ohio

[Mark_Moyle]

I'd bet the Stewart's system folks will come up with the same fix as the fuel tank/bay fix. Paint the interior belly with top coat...


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[Dan Gervae]

Any of you Stewart’s experts have this color variation between fabric and metal?...all from the same can, all parts were primed with white Ekoprime. It still looks fine, just wondering. I don’t want each round of parts I paint to come out different.

[Bearhawk Builder]

No. The only time I’ve had that is if the primer was a different color. Yellow sucks.

[J3Jim]

Any of you Stewart’s experts have this color variation between fabric and metal?...all from the same can, all parts were primed with white Ekoprime. It still looks fine, just wondering. I don’t want each round of parts I paint to come out different.

I’ve seen this before. I’ve heard some guys at shops talk about this n their solutions.
It’s not you. It’s a great question.


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[Dan Gervae]

I made sure I coated all parts very well with white ekoprime too...I really wanted to make sure I had a good base because of the yellow.

[tedwaltman1]

I have multiple shades of yellow. More noticeable between fabric and metal. Frustrating.

when I redid my cowl, I switched to PPG.

[RaisedByWolves]

You can take the rudder off or something of the sort, bring it to an automotive supply and they can scan and color match. Fun fact, color of primer and how many coats will change the yellow. An autobody trick is to prime a piece of scrap metal, paint it, then mask a section, another coat, mask, another coat.. and you can see how many coats to get the same color

[mike mcs repair]

As stated above. Yellow sucks!!! No mater what type or brand of paint. That’s why you must paint finish coat on all in one shot.


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[robertc]

I've done two yellow projects with Stewart's and all the fabric and metal parts match, but I can't tell you how it happens. It just does.

[bob turner]

The white is the key. Insignia white is best - even an ever so subtle change, like Juneau white, can change the finish color.

I am with Mike - matching yellows is almost hopeless. Did five repairs this lose, but no cigar.

[jimboflying]

Does yellow tinted primer work better or worse?

[bob turner]

You need white, because it is opaque, and covers in one coat.

[LMartin]

I just complete a PA-11 replica using Stuart system, using brushes and foam rollers. Satisfactory job but lots of work.

Warning: If you use auto gas when, for the first time, you put fuel in your tanks and if there is a fuel leak, it will disolve the EkoFill and the top coat will fall off where fuel drops hit the inside of fuselage or wings. I talked to the Stuart experts and this fact is known to them. I live in Eastern Canada.

Thank you! That’s my biggest concern with Stewart paint. Has anyone tried topcoating with a solvent based paint like Superflite paint?

[supercrow]

I top coated some exp. tailfeathers a while back with aerothane and it worked out very well. Would cure the problem you are talking about.

[Steve Pierce]

The issue is the backside of the fabric not the top coat. Stewart System top coat is catalyzed polyurethane

[LMartin]

The issue is the backside of the fabric not the top coat. Stewart System top coat is catalyzed polyurethane

I’ve been reading that. I haven’t experienced it. We seemed to have trouble with the top coat, from fueling with cans. A friend that does a lot of traditional painting was talked into Stewart paint last fall and he also had to patch fabric and repaint when the owner spilled some fuel on top when using a can. In a perfect world we’d never spill anything, but that’s just not reality. It sound like all the components are just not durable enough? Maybe I should rip the fabric off and start over before I waste anymore time and money.

[Steve Pierce]

I don't see how spilling the top coat on the catalyzed polyurethane is cause a problem. It is like any catalyzed paint only it is carried via water vs solvents. Can you post some pictures?

[Marty57]

I don't see how spilling the top coat on the catalyzed polyurethane is cause a problem. It is like any catalyzed paint only it is carried via water vs solvents. Can you post some pictures?

Steve,
Not sure about LMartin but I have a picture of a sample that has been in 100LL since 12/12/17. I took this picture after reading your post for a picture. Most of the fuel has evaporated out of the jar but the paint has never bubbled or pealed from the fabric. When everything is done correctly, there should not be any issues.

Marty57

[tedwaltman1]

I had (and still have) the same problem with Stewart paint on my Cub. Any fuel tank leaks, always 100LL, start the outside paint to dissolve. I was told, but too late to try, that this is a known issue—a solution is to supposedly paint the inside of the fabric before putting the tanks in.

[Steve Pierce]

I had (and still have) the same problem with Stewart paint on my Cub. Any fuel tank leaks, always 100LL, start the outside paint to dissolve. I was told, but too late to try, that this is a known issue—a solution is to supposedly paint the inside of the fabric before putting the tanks in.

So if you spill paint on the tops of the wings it softens the paint?

[tedwaltman1]

No, of course not on the top (painted) fabric. Sorry for the confusion.

But any internal (eg commonly around say SAF-AIR fuel drain fittings, causes a problem. And I did have one tank (tiny crack) leak long ago, so have a deteriorated spot (now seen on the outside) from that leaking inside out..

[Steve Pierce]

No, of course not on the top (painted) fabric. Sorry for the confusion.

But any internal (eg commonly around say SAF-AIR fuel drain fittings, causes a problem. And I did have one tank (tiny crack) leak long ago, so have a deteriorated spot (now seen on the outside) from that leaking inside out..

Yea, that was my understanding, if the fuel got on the back side of the fabric. I remember when Jason Gerard was working for Stewarts and doing the seminars here he would Ekofil and paint inside the fuel tank bay.

[Marty57]

I had (and still have) the same problem with Stewart paint on my Cub. Any fuel tank leaks, always 100LL, start the outside paint to dissolve. I was told, but too late to try, that this is a known issue—a solution is to supposedly paint the inside of the fabric before putting the tanks in.

You are saying two different things here; fuel on top of the paint and paint under the fabrick, inside the fuel tank bay. Where are you having the problem? the picture I posted shows that there has been no effect after 5 years soaked in fuel ..... so properly done top coats will not be affected by 100LL. If you are having issues with fuel softening out paint than it isn't 100LL. I have another sample from same fabric that I put in CA auto gas, with alcohol (nasty stuff here in California). The fabric shed the paint, and it curled up in 30 seconds! Hence the warning, don't use ethanol based auto gas in an aircraft .... especially CA gas.

For your second statement, yes, we do recommend top coating the inside of the fuel tank well to prevent fuel getting to the glue; that can cause issues. By doing that step, any fuel that gets inside the tank bay will have no effect ..... if it's 100LL. Auto gas can have any additives that the region wants to use for their states EPA regulations so no telling what is in the fuel so be very careful with auto gas, even pure MO gas. I can guarantee you that properly mixed and applied EkoPoly Premium or EkoCrylic top coats will not dissolve in the presence of av gas. If it were to dissolve, do you think the FAA would have awarded an STC for the use of our system on certified aircraft? If you think that your paint is defective, remove a sample and send it to us to test; otherwise we have no way of fully understanding your issues. Remember, blue staining is not the paint dissolving. Please post some actual pictures of your paint dissolving so we can help remedy the situation.

Marty57

[Gordon Misch]

Thing is, at least in my experience from 12 years ago, fuel on the inside will release the finish coat from the under-layer, making it wrinkle and detach.

Edit: Could be that more recent formulations may have mitigated that.

[Marty57]

Thing is, at least in my experience from 12 years ago, fuel on the inside will release the finish coat from the under-layer, making it wrinkle and detach.

Edit: Could be that more recent formulations may have mitigated that.

The sample I posted a picture of has been in 100LL since 2017; testing the fuel to extended immersion in fuel; no affect noted. The comments above that the top coat is softened by fuel is, of course, not accurate. The sample I tested does not have any EkoBond on the fabric. The manual is very upfront about keeping EkoBond away from prolonged immersion in fuel and how to properly finish those areas. Like any fabric system, proper application is essential to prevent issues with the finished fabric. Section 10 of the manual outlines how to finish around areas subjected to fuel spillage. Resistance to 100LL is part of the FAA certification process. Auto gas, on the other hand, has no certification standard and can possibly affect any fabric system as there is no way to test for all the components that may be used in auto gas.

The new formulation is a reference to the change made to the paint to extent it's pot life from the original 45 minute pot life to current 2-1/2 to 3 hour pot life. Other than that, there weren't any changes to the system as related to Aviation fuels.

Marty57

[Gordon Misch]

Yes, I was using partly mogas and partly avgas. There was a very slow fuel valve leak.

[ak49flyer]

I’ve never understood the “paint the inside of the tank bay, and that’ll solve the problem” theory- fuel just runs aft of the rear spar, where the backside isn’t painted, and the wrinkles begin. Been there, done that on multiple planes…

[Steve Pierce]

Hopefully it would drain out the drain holes and evaporate but who knows.

[Marty57]

Hopefully it would drain out the drain holes and evaporate but who knows.

That's exactly what we call out for in the manual; section 10 to be specific. If fuel can't drain out of a covered wing, I suspect any system will encounter issues.

Marty57

[ak49flyer]

So then why paint inside the tank bay at all- it’ll just run out the drain grommets…?

[Steve Pierce]

Being proactive I guess, every little bit helps.

[Marty57]

So then why paint inside the tank bay at all- it’ll just run out the drain grommets…?

Drain grommets sometimes become plugged. Here's the center section of a Waco I painted. Painting the fuel tank bays did not take any extra time or preparation. This is not a big deal to do. In the case of this Waco, along with the possibility of a fuel spill, I did not know what glue was used in the restoration. So, being cautious regarding both glue and fuel, and following the STC instructions, I painted the inside of the tank bay. When using an STC'd covering process on a certified aircraft, it is best to follow the STC. Following our manual is a requirement of the STC. As such, we outline the proper procedure for areas that may come in contact with fuel, as in a spill. From Rev. 4, section 10:

1)On the inside of fuel tank bays, fuselage low points and areas where fuel lines run, seal the inside of the fabric by painting it with EkoPoly Premium. This can be sprayed if convenient but can also be brushed or rolled. If it is not possible to access the inside of the tank bay, it is acceptable to seal the weave of the bare fabric in that area with EkoPoly Premium from the outside. Clear EkoPoly Premium is the best for that application. Mix it normally as you would for a spray application, but a slightly heavier viscosity may be desired. It will need lightly scuffed before applying EkoFill for good adhesion.


As with any STC it is best to follow the data provided within manual for that STC to satisfy the FAA. Deviating from the approved methods for any STC could render the aircraft non airworthy in the eyes of the FAA.

I hope this clears up any questions about fuel and Stewart Systems paint.

Marty57



Marty57