Steve's Aircraft (Brian)
FRIEND
White City, Oregon
Mary,
Got some on the way to you...
BTW... My cub in my avatar fuselage is covered in Stewarts...
Brian.
Observations on Stewarts System
- Thread starter wdoubleday
- Start date
Mary,
Got some on the way to you...
BTW... My cub in my avatar fuselage is covered in Stewarts...
Brian.
Dave Calkins
Registered User
Anchorage, Alaska
bummer on the ekobond
That means fuel attacking and debonding your work. Not just cosmetic. But a serious airworthiness issue.
That means fuel attacking and debonding your work. Not just cosmetic. But a serious airworthiness issue.
Marty57
PATRON
Nipomo, Ca
So far, only an issue with CA auto gas with ethonal. Mogas without ethanol was tested without any issues. There is some kind of additive in ethanol based California fuel that is culprit. Same test with ethanol fuel in Ohio showed no lifting of the paint and no debonding. Samples I have in 100 LL still show no lifting after three weeks. I’ll run same test with CA ethonal fuel on Polyfiber to compare.
Marty
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Marty, I got some lifting with WA non-alcohol mogas, that was slow-dripping on the inside of fuselage under the fuel selector valves. 2011 formulation.
Marty57
PATRON
Nipomo, Ca
Gordon,
Andy (Stewart Systems owner) and I have been discussing the issue of auto fuel lately. His Stinson is a Poly-Fiber finish and he has tapes lifting from a previous owner's use of auto fuel. That being said, the difficulty today is predicting what is in the fuel, ethanol or non-ethanol. Your situation is rare from Andy's experience but it has happened, similar to his Poly-Fiber tapes lifting.
I'm very curious about the different fuels around the country. This coming summer, on my way to Oshkosh, I plan on taking fuel samples at each state I pass through and testing them with fabric from the same painted panel I recently tested here. By doing this, the variable will be the fuel by state, not the fabric application. It won't be a truly scientific experiment but it will give me an idea of the different blends. When traveling from California to Wisconsin, I am amazed at the different smell of auto gas from one region to another. Here's a link to the standards adopted in CA: https://www.arb.ca.gov/fuels/gasoline/cbgupdat.htm
When you read the changes made to CA fuel, it mainly is in the form of reducing different ingredients in the fuel to make it burn cleaner, one being ethanol. My limited knowledge of fuel additives makes me think that if you remove additives A,B, and C from the fuel, you must add X,Y, and Z to keep the fuel performing at required levels. Again, what is being added? The link above mentioned the EPA requiring major metro areas that have high pollution to adopt the CA standards for their region's fuel supply. So, what is in the fuel? Not sure. It will be interesting to conduct some tests as I travel this summer.
Marty
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Good for you Marty - that should be an interesting experiment!
algonquin
MEMBER
Seldovia,Ak
So the bottom line would be stay with 100LL for the time being. I'm sure it won't be that long before we have a good answer to all this. I plan on telling the folks that I've used the Stewart's system on there aircraft to only use 100LL , but I think they already do.
bob turner
Registered User
Ca fuel? Awk! It used to have MTBE, whatever that is, and it would eat tank slosh - but not digest it.
I run very small Stromberg carbs, and can tell you that California gas doesn't seem to harm them. It also doesn't seem to bother my ancient Mustang convertibles, and has no effect on dope, acrylic enamel, or poly tone. I cannot tell you that I use gas with alcohol in it, because that would be an admission of guilt, at least in airplanes not certificated experimental.
But I have had my Cub in California since 1967, and fly it every darn day. So far, so good.
I run very small Stromberg carbs, and can tell you that California gas doesn't seem to harm them. It also doesn't seem to bother my ancient Mustang convertibles, and has no effect on dope, acrylic enamel, or poly tone. I cannot tell you that I use gas with alcohol in it, because that would be an admission of guilt, at least in airplanes not certificated experimental.
But I have had my Cub in California since 1967, and fly it every darn day. So far, so good.
Hardtailjohn
Registered User
Marion, MT
It isn't necessarily state to state. When I hauled fuel, we were a Union 76 dealer. We loaded at the same Texaco loading rack as the Texaco, Arco, Shell, Conoco, and a few independent dealers. I remember the Texaco guys used to have to add the "Texron" to their loads....about 2 quarts to a 10,000 gallon load. They got it in big plastic bottles at first, but if it didn't get used within a few days, it ate through the bottle! They wound up using steel bottles. We also bought a million gallon load of unleaded car gas from an outfit in Ballard, called "Time Oil".... it was just the color of tea. And it stunk. We started having issues with the valves in our piping systems on the trucks not long after we started hauling it. I guess what I'm saying is that there's some absolutely AWFUL stuff that goes in car gas. I'd rather not run it through my airplane. The quality control is nothing like it is for aviation fuel. I've tested Stewarts (long before it was Stewarts) and Poly fiber in different car gas and had mixed results throughout. The other thing to keep in mind is that quite often stations or stores will change suppliers so you really never do know what you're getting with car gas.
John
John
This is just out of the paint booth and I should have quit 2 minutes before I did. Solvent blister on the trailing edge of the flap. I'm out of practice spraying Stewarts but it will bite if too thick. I have had these blisters come up weeks and months after the paint was applied in areas that are thick.
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Bart23Sept
Registered User
Pittstown, NJ
I saw in one of the videos that you have about ten minutes to spray once the catalyst is added and the mixed is diluted/stirred to the right viscosity. Do you go strictly by time or is there something to watch or listen for as you're spraying to indicate time's up?
Thanks.
Bart
Hardtailjohn
Registered User
Marion, MT
Potlife is 3-4 hours, not ten minutes. So don't hurry!! I've been teaching this stuff for over 20 years and the number one problem people have with the topcoat is that they get in a hurry!! Any polyurethane has a definite window when it's ready to receive the next coat. Some solvent based polyurethanes I've shot have a very narrow window, and some have a very wide window. Stewarts actually has a very nice wide window. Take your knuckle and rest it on the painted surface. When it's ready to receive the next coat, you wont have any transfer of paint to your knuckle when you remove it, but it will feel very sticky, like fly paper. Sometimes with the right conditions and coat thickness, that takes as little as 10 minutes to happen.....sometimes it can take 40. Airflow across the surface and temperature/humidity have a big influence on this. I don't care how long it's been, as long as it's ready. You don't want to let it get too dry before the next coat...optimum is to monitor the surface every few minutes until it is ready. Too long and you lose the sticky feeling (I tell students that it should feel like fly paper) and you have to let it dry overnight and hit it again tomorrow. Remember, water is the carrier or solvent for this topcoat, and it doesn't evaporate as quickly as solvent. Usually I have to leave the booth and go in another room or I get impatient and screw it up. (old habits die hard!) In that same sense, this paint will flow out longer than solvent borne paints, so as I tell students, 5 light coats will look better than 3 heavy ones in a day or so.
John
jimboflying
MEMBER
I covered and painted the wings with the Stewarts system. The custom yellow color doesn’t match the tail feathers which were done in Polyfiber poly tone. It has been suggested that I rejuvenate the polytone before topcoating with the Stewarts polyureathane. Will the rejuvenator process interfere with the bonding of the Stewarts topcoat?
Hardtailjohn
Registered User
Marion, MT
Your topcoat is no better than what's under it, so I'd rejuvinate and let it be for a couple months, then go ahead with the topcoat.
John
John
jimboflying
MEMBER
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mike mcs repair
Registered User
chugiak AK
leaking pipe thread at tank quick drain ????
or?? your point you are trying to demonstrate is????
confused....
jimboflying
MEMBER
Leaking quick drain which caused the paint to bubble and peel. Is this normal?
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
In my experience, Stewarts withstands gas just fine on the outside, but not so much from the inside. Maybe partly (or maybe entirely) because if the gas is on the inside it's from a leak and is there over an extended period of time?
How do other systems respond to gasoline immersion? I have no idea??
Edit: I have some Stewarts System fabric I recently removed from a control surface. I think I'll see if I can immerse only the painted side in some gas and see what happens.
How do other systems respond to gasoline immersion? I have no idea??
Edit: I have some Stewarts System fabric I recently removed from a control surface. I think I'll see if I can immerse only the painted side in some gas and see what happens.
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Currently redoing a wing that had the whole tank bay look like that after a leak- have seen it other times too- all auto-gas (non ethanol) as far as I can tell; avgas doesn’t seem to affect it... What Gordon said- it’s always from inside- seems impervious on the outside- spills, etc...
mike mcs repair
Registered User
chugiak AK
leaking gas causes stains no mater what system....
FYI best cleaner for the blue stains is.. more blue gas.. and prayers you don't cause a spark...
Marty57
PATRON
Nipomo, Ca
I have a sample of Stewart Systems in a jar of 100LL now for over 6 months with absolutely no affect. Autogas, however, lifted the paint exactly as in the pictures above in a mater of minutes. I tested a piece of fabric painted in Polyfiber in CA auto gas. The paint did not lift, it simply swelled about three times the thickness at the edges, very strange reaction. It's not just the ethanol in the gas, it's all the additives. There is simply no way to formulate a paint to resist auto gas due the the fact that their are no national standards. California uses completely different additives to oxygenate the fuel than other states. Due to that, ethanol free auto gas might still have issues due to the junk added to the fuel. For a fuel tank bay, we recommend painting the interior of the bay up through EkoPoly top coat. For 100LL, there won't be any issues.
I recently repaired a Super Cub that had used auto fuel with ethanol. The fuel selector leaked and fuel settled along the lower longeron near the front gear attach and lifted the paint exactly as in the picture. The plane was painted in Stewart Systems. If you use any auto fuel anything can happen depending oh where the fuel came from. I wish I had a better answer but auto gas is bad stuff now a days.
Marty
I recently repaired a Super Cub that had used auto fuel with ethanol. The fuel selector leaked and fuel settled along the lower longeron near the front gear attach and lifted the paint exactly as in the picture. The plane was painted in Stewart Systems. If you use any auto fuel anything can happen depending oh where the fuel came from. I wish I had a better answer but auto gas is bad stuff now a days.
Marty
coxcub
PATRON
Devon, England
Slightly off Topic but how sensitive is Stewarts to Temperature/humidity? I live in the land of the '40 knot fog' where 2/3s of the year is very damp. Poly Fiber went on perfectly in temps of 65ish with 75-80% humidity. I would be very interested to use Stewarts but am not keen to see high electricity bills!
Many thanks
Frank
Many thanks
Frank
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Interesting Marty! I'll try the same with some Washington non alcohol mogas.
Steve Pierce
BENEFACTOR
Graham, TX
I remember Jason painting the inside of the tank bays on the wings we covered here so this would not be an issue. I have a Tri-Pacer in the hanger now with a similar issue that was done in dope.
Hardtailjohn
Registered User
Marion, MT
It can be done, but you need to understand that the thinner and carrier for the products it water, so it will be very slow to evaporate compared to a chemical solvent.
John
algonquin
MEMBER
Seldovia,Ak
I've done a couple jobs in the Northeast which is high humidity and cool and had no problem at all.
Marty I tried thinning the Ekobond and brushing it on the fabric as a base coat. Pleasantly surprised how nice it worked, I didn't have any fresh Ekofill so had to wait to finish up, hope there isn't any problem leaving it that way for a month.
Marty I tried thinning the Ekobond and brushing it on the fabric as a base coat. Pleasantly surprised how nice it worked, I didn't have any fresh Ekofill so had to wait to finish up, hope there isn't any problem leaving it that way for a month.
Marty57
PATRON
Nipomo, Ca
You won't have any issues waiting; might pick up a little dust is all. My flaps, ailerons, and tail feathers are sitting in our master bedroom in just the same configuration. Yeah, I have a very understanding wife ;-)
Marty
This seems to work fine for the areas that actually get painted (between the spars). But I’ve had a couple wings that had leaks that ran behind the spars and bubbled/lifted paint and even softened the glue to the point of letting go. Evidently auto gas/Stewart’s just isn’t a compatible situation...
Marty57
PATRON
Nipomo, Ca
I would have to say that auto gas is a crap shoot with any system. The two samples I have in auto gas, one Stewart Systems and one Polyfiber have both reacted to the additives in CA auto gas. The Polyfiber swelled, the Stewart Systems softened and curled, separating from fabric. If a pilot is using auto gas, not sure what the solution is. The new Rotax is certified to run on 10% Ethanol fuel; that will likely damage any covering system depending on the additives in a given state. I'll stay away from autogas and use the 94UL where available or 100LL. I wish I had a better solution. I still have the samples in 100LL and no reaction since December.
Marty
Love the Stewart product....gas does seem to be a weakness...the next time I do a pain, I will paint the fuel tank bays as well. I painted my Exp Cub back in 2009, and the only blemish is from a fuel leak. I will certainly continue to use the Stewart product.
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