Based on the G100UL fuel leak thread what's your position?

[Kelpro999]

6 hours ago, A64Pilot said:

What’s the storage life of this stuff if let in vented containers?

 My concern from the beginning 

[Schllc]

20 hours ago, philiplane said:

may have substandard paint jobs consisting of improperly cured substrates or top coats.

The “substandard methods” appear to have been adequate to resist all factors prior to now, which would seem to at a minimum diminish your assessment of what is adequate. 
if it withstood all chemical and environmental conditions before g100ul, why is it now substandard?

[toto]

15 hours ago, A64Pilot said:

Does anyone know the person who posted the Youtube video of problems? Is the video still up? Has he received a letter?

Both of the videos are still up. I saw that @mluvara joined MS recently, but I have no idea whether this user has any connection with the YouTuber.

These videos have been super influential on MS, and it would be fantastic to have the creator participate in the discussion. But it’s also obviously a hot-button topic and I wouldn’t second guess anyone’s decision not to get involved. 

[Fly Boomer]

On 1/22/2025 at 7:44 AM, A64Pilot said:

Be very sure the polish you pick does NOT have silicone in it

Meguiars uses the phrase "body shop safe" to identify products that don't have silicone or any other ingredients that could interfere with paint.  This document answers the question "Is it body shop safe"?

Meguiars Body Shop Safe.pdf

 

[mluvara]

On 1/22/2025 at 8:22 PM, toto said:

Both of the videos are still up. I saw that @mluvara joined MS recently, but I have no idea whether this user has any connection with the YouTuber.

These videos have been super influential on MS, and it would be fantastic to have the creator participate in the discussion. But it’s also obviously a hot-button topic and I wouldn’t second guess anyone’s decision not to get involved. 

Hi All,

Yes, I’m here on Mooneyspace. Never owned one, but I have a few hours in a friend’s Mooney (which was sold and is the infamous Mooney that later flew through Area 51).

Anyways, I’m happy to clarify if something was not clearly stated in the videos. 

As to not clutter the already long thread, please send me a direct message with your question(s) over the next few days and I’ll try to summarize applicable comments in one response. I just ask that you’ve reviewed the videos (Part 1) (Part 2) to ensure your question is not already covered there. I spent a lot of time compiling the videos and it has been quite frustrating to watch comments on many forums where it is clear people have not watched the videos.

I want to reiterate that my initial primary focus was on the effects & compatibility to my personal aircraft. And based on what I learned, I performed more testing and decided to share the results.

I do think it is unfair to blame paint jobs being the cause, as 100LL historically seems to do very little, if anything, to painted surfaces. I’ve verified that through the course of my testing.

I really want unleaded fuels to work. I’d do the same testing for any other fuel that came to market which I had questions about. Especially so since this is the application of an STC (major alteration) and the A&P/IA has to determine if the modification is compatible with the aircraft. 

I thought this recent commentary by Darren Pleasance (new AOPA CEO) echoes many of my sentiments. https://www.aopa.org/news-and-media/all-news/2025/january/23/presidents-position-on-unleaded-fuel

Michael

 

Edited January 24 by mluvara

[gabez]

we got this yesterday 

[A64Pilot]

On 1/24/2025 at 10:25 AM, Fly Boomer said:

Meguiars uses the phrase "body shop safe" to identify products that don't have silicone or any other ingredients that could interfere with paint.  This document answers the question "Is it body shop safe"?

Meguiars Body Shop Safe.pdf 1.22 MB · 4 downloads

 

Interesting thanks, it lists machine glaze as yes, but it sure felt like it has silicone.

[MikeOH]

2 hours ago, A64Pilot said:

Interesting thanks, it lists machine glaze as yes, but it sure felt like it has silicone.

That was a pretty extensive list.  Point being, there might be mistakes. I'd give them a call if I really wanted to be sure about one of the products.

[A64Pilot]

Silicone isn’t the end of the world, it doesn’t last, a couple of car washes and it’s gone. I just think they should have told me if something other than a very fine compound was there. Silicone as far as I can tell is harmless.

Issue for me was I was prepping my new to me Jeep for Rejex, which is a polymer and ideally anything that bonds to paint or even wax that’s a coating you want clean paint surface with no type of coating on it and using the Mequires it left a slick feel to the paint, so there was something, perhaps a wax, I assumed silicone because that’s what most use to get a shiny appearance, silicone is cheap and easy for them, but it doesn’t last.

I stopped with the Meguires and used the 3M, it easily cleaned off whatever the coating that Mequires had left.

[George Braly]

On 1/19/2025 at 5:52 PM, MikeOH said:

No, it’s not! If it does NOT leak with 100LL and does with some other fuel THAT is a problem.

This idea that we are suppose to accept a product that damages our aircraft when 100LL does not is completely irrational.

 

 

With respect to your observation:  "If it does NOT leak with 100LL . . . "

Mike,

Integral (non-bladder non-welded) aluminum - riveted fuel tanks have been leaking  (on 100LL ) within relatively short periods of time (2 to 10 years after original construction) since at least the 1970s.

There are three long term repair shops that specialize in cleaning and re-sealing Mooney integral fuel tanks (and others of similar construction.) 

Examples:   

1)  Mooney fuel leak 100LL

https://youtube.com/shorts/rMqENgH2udo?si=5_aVNdzOYtqxfmmI

 2) Identifying a leak on a Vans RV-10 fuel tank - 100LL

https://youtube.com/shorts/-zXeFLsfUhU?si=F09FtUxW26eAUmIS

3) Cirrus SR20  fuel leak from 100LL

https://youtube.com/shorts/3j53EHFpVzo?si=0RZa31jYdr8QhUg6

4)  Resealing a  leaking Piper fuel tank.

https://youtube.com/shorts/K4FwEgt86iQ?si=21tI-6xqaaDxKHD8

 

[gabez]

24 minutes ago, George Braly said:

 

With respect to your observation:  "If it does NOT leak with 100LL . . . "

Mike,

Integral (non-bladder non-welded) aluminum - riveted fuel tanks have been leaking  (on 100LL ) within relatively short periods of time (2 to 10 years after original construction) since at least the 1970s.

There are three long term repair shops that specialize in cleaning and re-sealing Mooney integral fuel tanks (and others of similar construction.) 

Examples:   

1)  Mooney fuel leak 100LL

https://youtube.com/shorts/rMqENgH2udo?si=5_aVNdzOYtqxfmmI

 2) Identifying a leak on a Vans RV-10 fuel tank - 100LL

https://youtube.com/shorts/-zXeFLsfUhU?si=F09FtUxW26eAUmIS

3) Cirrus SR20  fuel leak from 100LL

https://youtube.com/shorts/3j53EHFpVzo?si=0RZa31jYdr8QhUg6

4)  Resealing a  leaking Piper fuel tank.

https://youtube.com/shorts/K4FwEgt86iQ?si=21tI-6xqaaDxKHD8

 

what's your point? Tanks leak yes. do all our tanks decided to start leaking within a week of using G100UL? I doubt it.

[Marc_B]

@George Braly  Respectfully, there's a difference in a wet wing that leaked shortly after sealing (due to bad sealant, improper technique, or due to damage to the structure) and a leak that results from the implementation of a new fuel.

You are quick to condemn the Mooney sealant technique, Cirrus application technique, and wet wings in general.  But the hard reality is that these are 100% a part of not only the general aviation fleet, but a standard practice to use wet wings in aviation in general.

It is very clearly understood that you want to convey that any leaks seen from using G100UL are due to poor sealant product, poor sealant application, and wet wings in general.  But there are lots of Mooneys on here, and out there, who have seen 25-40 years before substantial leaks on their wet wings requiring resealing. 

It's yet to be seen if G100UL will be able to have the same track record.

It's also more concerning if cases of leaking G100UL may result in significant paint damage when that's not typically something that has been routinely seen with 100LL.

Certainly there is benefit to having the BEST paint, the BEST sealant, the BEST hoses/o-rings/etc for the job.  BUT for a fleet of aircraft that spans back to the 1960's (and in some cases much older) all the way to today, there are exceedingly few that have the newest and best currently and the best for long.  In our minds, "drop in fuel" means fly what you have.

 

[Schllc]

1 hour ago, George Braly said:

Integral (non-bladder non-welded) aluminum - riveted fuel tanks have been leaking  (on 100LL ) within relatively short periods of time (2 to 10 years after original construction) since at least the 1970s.

I don’t want to make assumptions, but it sounds like you are suggesting that tanks that have not leaked yet with 100LL have issues that have not manifested until g100UL was introduced?  
This may well be true, but if the wrong sealant, or poor workmanship was sufficient for 100LL, why would gami push it over the edge?

I suppose I am resigned to the reality that this issue will likely be pushed on us prematurely, regardless of the challenges, so I would think most of us just want to know what the issues actually are. 
 

I am getting ready to paint my Mooney. I have zero evidence of any leaks this far, and my inspections of the sealant show it to be in very good condition. 
The plane was likely sealed around 2006, given it is a 2007 year model,  and given that it’s been 20 years with no issues, no repairs to be suspect of, I see no reason to reseal my tanks prior to paint.  I also have no reason to believe the Mooney factory would use the wrong sealant. 
What I have done is ask scheme designers who is helping me write a paint specification, and they contacted Gami for help tailoring the paint spec.  This is to ensure I don’t use “substandard”, products and methods, and to avoid having paint failures if I have to use gami’s fuel in the future. 
There has been so much discussion regarding wrong paint, bad sealant, improper materials etc etc. 

I would hope you guys can provide some guidance so if I do have a paint failure, so it won’t be a result of the interaction between my work and your fuel. 

Bottom line, what is the “right” sealant, paint, primer should I use to avoid adverse reactions with your fuel?

[gabez]

11 minutes ago, Schllc said:

Bottom line, what is the “right” sealant, paint, primer should I use to avoid adverse reactions with your fuel?

That is a very great question. And after GAMI answers it please also answer how does it stack again their marketing claims of "drop in"

[George Braly]

21 minutes ago, Schllc said:

I don’t want to make assumptions, but it sounds like you are suggesting that tanks that have not leaked yet with 100LL have issues that have not manifested until g100UL was introduced?  
This may well be true, but if the wrong sealant, or poor workmanship was sufficient for 100LL, why would gami push it over the edge?

I suppose I am resigned to the reality that this issue will likely be pushed on us prematurely, regardless of the challenges, so I would think most of us just want to know what the issues actually are. 
 

I am getting ready to paint my Mooney. I have zero evidence of any leaks this far, and my inspections of the sealant show it to be in very good condition. 
The plane was likely sealed around 2006, given it is a 2007 year model,  and given that it’s been 20 years with no issues, no repairs to be suspect of, I see no reason to reseal my tanks prior to paint.  I also have no reason to believe the Mooney factory would use the wrong sealant. 
What I have done is ask scheme designers who is helping me write a paint specification, and they contacted Gami for help tailoring the paint spec.  This is to ensure I don’t use “substandard”, products and methods, and to avoid having paint failures if I have to use gami’s fuel in the future. 
There has been so much discussion regarding wrong paint, bad sealant, improper materials etc etc. 

I would hope you guys can provide some guidance so if I do have a paint failure, so it won’t be a result of the interaction between my work and your fuel. 

Bottom line, what is the “right” sealant, paint, primer should I use to avoid adverse reactions with your fuel?

Schllc,

Give me a call tonight or tomorrow sometime.  I would like to discuss this with you.  580 421 5645 is my cell number.

Do you have borescope pictures of the inside of your Mooney fuel tanks ? 

George

PS.  As an interesting coincidence:  - - My name is on some of the original 1967 engineering drawings  when (in the engineering room at Northridge, Ca.) we redesigned the Aerostar wing tanks (which had, for the Aerostar "360 & 400", previously been "dry wings" - - to become "wet wings."    That was for the prototype and then the production series of Aerostar 600,601, & 601P models.  

 

[Schllc]

4 minutes ago, George Braly said:

Schllc,

Give me a call tonight or tomorrow sometime.  I would like to discuss this with you.  

Do you have borescope pictures of the inside of your Mooney fuel tanks ? 

George

PS.  As an interesting coincidence:  - - My name is on some of the original 1967 engineering drawings  when (in the engineering room at Northridge, Ca.) we redesigned the Aerostar wing tanks (which had, for the Aerostar "360 & 400", previously been "dry wings" - - to become "wet wings."    That was for the prototype and then the production series of Aerostar 600,601, & 601P models.  

 

Great,  because I have an Aerostar with wet wings as well!

I do not have borescope pictures but it is going in for some significant maintenance shortly, and will include changing the style of fuel caps, so I will have a pretty large section open for inspection.  Paint isn’t happening until the summer. 

[George Braly]

21 hours ago, Marc_B said:

@George Braly  Respectfully, there's a difference in a wet wing that leaked shortly after sealing (due to bad sealant, improper technique, or due to damage to the structure) and a leak that results from the implementation of a new fuel.

You are quick to condemn the Mooney sealant technique, Cirrus application technique, and wet wings in general.  But the hard reality is that these are 100% a part of not only the general aviation fleet, but a standard practice to use wet wings in aviation in general.

It is very clearly understood that you want to convey that any leaks seen from using G100UL are due to poor sealant product, poor sealant application, and wet wings in general.  But there are lots of Mooneys on here, and out there, who have seen 25-40 years before substantial leaks on their wet wings requiring resealing. 

It's yet to be seen if G100UL will be able to have the same track record.

It's also more concerning if cases of leaking G100UL may result in significant paint damage when that's not typically something that has been routinely seen with 100LL.

Certainly there is benefit to having the BEST paint, the BEST sealant, the BEST hoses/o-rings/etc for the job.  BUT for a fleet of aircraft that spans back to the 1960's (and in some cases much older) all the way to today, there are exceedingly few that have the newest and best currently and the best for long.  In our minds, "drop in fuel" means fly what you have.

 

Marc,

I wish I had the band-width to jump into this with more time and data.   

However, claims that 100LL does not damage paint - - are contrary to lots of observations from the field.

Let me try to verify the source of the fuel in that photograph - - in the mean time, I deleted it from the post.  

I apologize for any confusion.

Let me try to get better data.

In the mean time, I have to (get to) go fly a new experimental turbo system!   

George 

 

Edited January 27 by George Braly
to verify the data . . .

[mluvara]

9 minutes ago, George Braly said:

Marc,

I wish I had the band-width to jump into this with more time and data.   

However, claims that 100LL does not damage paint - - are contrary to lots and lots of observations from the field.

Consider the following, which I just happened stumble across today when hunting for another document.

Are you saying that the photos in the PAFI lessons learned (page 7) are misleading and not from a candidate fuel, but from 100LL?

 

https://www.faa.gov/sites/faa.gov/files/PAFI_Fuel_Development_Testing_Lessons_Learned.pdf

[PT20J]

I had an interesting conversation yesterday with Brandon Rakes who is the manager of the Chehalis WA airport. They recently put in two12,000 gallon above ground tanks (100LL and JetA). Cost all in (engineering, site prep, tank and pump equipment purchase, installation, permits, etc.) was $1.2-million. He said they considered a third tank for unleaded but could not figure out how to make it pencil out assuming they will only need a single avgas tank in 5 years if 100LL goes away.

[philiplane]

On 1/22/2025 at 5:13 PM, Schllc said:

The “substandard methods” appear to have been adequate to resist all factors prior to now, which would seem to at a minimum diminish your assessment of what is adequate. 
if it withstood all chemical and environmental conditions before g100ul, why is it now substandard?

Substandard only reveals itself when challenged. I find substandard materials when I try to spot repair damage. I don't expect peeling and bubbling, but that happens when you try to blend paint work into existing paint work that someone "cheaped out" on the primer, or used a cheapo hardener, instead of the correct (costly) products. I suspect that this is what the G100UL is revealing. Since it has more solvent action than 100LL, it is not surprising that some leaky planes are experiencing paint problems. Those problems would also occur if they needed sheetmetal repairs, but no one would know about it. The shop would simply find a way around it, and bill the customer accordingly.

[MikeOH]

3 hours ago, George Braly said:

 

With respect to your observation:  "If it does NOT leak with 100LL . . . "

Mike,

Integral (non-bladder non-welded) aluminum - riveted fuel tanks have been leaking  (on 100LL ) within relatively short periods of time (2 to 10 years after original construction) since at least the 1970s.

There are three long term repair shops that specialize in cleaning and re-sealing Mooney integral fuel tanks (and others of similar construction.) 

Examples:   

1)  Mooney fuel leak 100LL

https://youtube.com/shorts/rMqENgH2udo?si=5_aVNdzOYtqxfmmI

 2) Identifying a leak on a Vans RV-10 fuel tank - 100LL

https://youtube.com/shorts/-zXeFLsfUhU?si=F09FtUxW26eAUmIS

3) Cirrus SR20  fuel leak from 100LL

https://youtube.com/shorts/3j53EHFpVzo?si=0RZa31jYdr8QhUg6

4)  Resealing a  leaking Piper fuel tank.

https://youtube.com/shorts/K4FwEgt86iQ?si=21tI-6xqaaDxKHD8

 

@George Braly

Your response confused me as I thought it obvious from your previous criticisms of existing 'old' tanks that you would understand my point:  My existing tanks are NOT causing me a problem with 100LL.

As near as I can tell from the logs they have never been stripped and resealed; that's 55 years.  Yes, they have been patched several times, including twice for the right tank during my 7 years of ownership; the left has never given me need to.  IOW, very low cost tank maintenance.  Any and all 'stains' from an occasional spill have been EASILY and completely cleaned by a rag dipped in 100LL!  Even if that's a week later, or more, later.

I suspect that I'm NOT the only one in this situation: a perfectly acceptable tank state; not perfect, but NOT requiring a $14,000 reseal.  The fact that, at some point in the future, that may be required does NOT justify the acceptance of ANY fuel that will move that future expenditure to the PRESENT.  Put another way, we are perfectly happy with the present state of our perhaps sub-standard, but acceptable, tanks and do NOT wish to jeopardize that situation.

[gabez]

32 minutes ago, philiplane said:

Since it has more solvent action than 100LL

where was that disclosed by GAMI? 

[ragedracer1977]

On 1/24/2025 at 9:39 AM, mluvara said:

I spent a lot of time compiling the videos and it has been quite frustrating to watch comments on many forums where it is clear people have not watched the videos.

 

 

Thanks for putting yourself out there.  I know it drives ME nuts reading comments from people who clearly didn’t bother to watch.  I can only imagine your frustration.

[ragedracer1977]

3 hours ago, George Braly said:

Marc,

I wish I had the band-width to jump into this with more time and data.   

However, claims that 100LL does not damage paint - - are contrary to lots and lots of observations from the field.

Consider the following, which I just happened stumble across today when hunting for another document.

Where did you find this image, exactly? Did you add the caption or was it found that way?  
 

you should probably be aware that that is NOT damage from 100LL and could, in fact, be damage from G100UL

[redbaron1982]

3 hours ago, George Braly said:

Marc,

I wish I had the band-width to jump into this with more time and data.   

However, claims that 100LL does not damage paint - - are contrary to lots and lots of observations from the field.

Consider the following, which I just happened stumble across today when hunting for another document.

That's odd. If that were from 100LL, I would expect to see some blue staining, but instead, there is some brown residue.

It is disturbing that the same photos are in the PAFI document of Lessons Learned.

Providing the source of these pictures could help clear up the confusion.