TANKS - Weeping - Patch - Nuance

[Htwjr]

My C model was weeping when I got it from the right tank. i flew it for a year or so until it got worse and started dripping. I used the Maxwell method to find the leaks and stripped just those areas before patching them myself with my A&P's oversight. That has been a couple of years ago flying from a grass strip and still weep free.  Maybe I was just lucky but I would not let a weep scare me off from an otherwise good plane.

[moontownMooney]

Regardless of advice on how to resolve the issue and how to navigate the purchase price, I agree that you shouldn't let a fuel weep scare you away from an otherwise good plane. Just be aware it will take some time and or money. But almost no plane of this vintage is issue free. I don't think you've said where the weep is, but a weep into the cabin is more serious and needs immediate attention. It isn't necessarily harder to fix but it does require immediate attention.

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[amillet]

@DonMuncy said”My plane and tanks are 36 years old, with probably more than average number of hard landings, and no leaks.”

I have always been afraid to make that statement. Afraid of the jinx.

[j3gq]

On 10/9/2018 at 10:15 PM, DonMuncy said:

So patching may be a very good answer for some and a very poor answer for others. And as near as I can tell, there is no good way to guess which is which. [...] Then take your best WAG, and go for it, knowing you may have guessed wrong. Naturally, a total reseal will likely solve the problem, but you may have been able to save money if you try to patch first.

While this seems all plausible, it misses one aspect. A leaking tank with original sealant can certainly be striped and re-sealed with a very high chance of long lasting success. Once your mechanic patched with "something magical" on top of the original sealant, your chances that the weep-no-more or similar chemicals can remove the entire sandwich of sealants may go down the drain. In this case your guess wasn't just wrong, you paid good faith money for destroying any chance of a future fix.

Does anybody have personal experience of the unpleasant kind with such a case ?

[RobertGary1]

18 minutes ago, j3gq said:

 In this case your guess wasn't just wrong, you paid good faith money for destroying any chance of a future fix.

Does anybody have personal experience of the unpleasant kind with such a case ?

Only such case I heard of was a plane at Lasar that a previous owner had sealed with furniture varnish.  But if you stick to using the stuff specified by the Mooney Maintenance Manual you should be fine.

-Robert

[j3gq]

In a similar post from 2013 scottfromiowa reported "My plane is being re-sealed (right tank) by Paul. He ran into trouble as the original owners A&P used silicone in the tank in an attempt to patch and Paul's stripping process would not "eat it". Paul has sealed 700+ tanks and mine was top five....worst he has seen"

My guess, you cannot trust every A&P or owner to stick to the MMM.

[j3gq]

Paul (weep-no-more) shared this photo with me last night when I asked about such weirdo cases mentioned before. He said this was one of the real messy cases he had to deal with, and his chemicals were up to the job. Sounds convincing, and I don't mean to hold out on you'll when the evidence is contrary to my expressed concerns.

[j3gq]

On 10/13/2018 at 9:00 AM, Htwjr said:

I used the Maxwell method to find the leaks

Hi Htwjr, when you say the Maxwell method, I suppose you refer to what is described here, right ?

http://donmaxwell.com/fuel-tank-repairs-how-we-fix-them/

[gsxrpilot]

On 10/10/2018 at 6:44 AM, ArtVandelay said:

I would only attempt to patch maybe once, next leak I would have a reseal.
For reseals I assume most do both tanks? Has anyone tried resealing just the leaky tank?

I had Houston Tank seal just my one leaky tank. I'm glad I did as he found some corrosion and I had to fly the plane out of there. If both tanks had been stripped, it would have been very difficult. 

[mike_elliott]

typically, patching a tank is a temporary fix for leaking tanks. This is not saying the patch started to re leak, it is saying the sealant most likely is brittle and will spring new leaks. When this happens, you can take the Robert Gary way of patching constantly or get the job done right.

Leaving your plane sit out in the sun with minimal fuel will exasperate this sealant deterioration, as well as being hard on paint, avionics, plexiglass and interior, per Paul Beck and Carl Sharon. Tank corrosion (well, all corrosion) will be minimized if you dont have water entering into the tank, and a hangar will minimize that.

 

[N201MKTurbo]

I think humidity has a more detrimental effect than than heat. My old F model sat outside in Arizona for 20 years and I never topped my tanks unless I was going somewhere. That plane had the factory sealant and never leaked a drop.

I have noticed that when I wash out the soap, used to look for leaks, with water, that the sealant changes color. this indicates that it is absorbing water and changing its properties somewhat. It will change back after it dries, but it does indicate that water affects it. How detrimental it is in the long run I don't know.

And #mike_elliott your experience with heat is probably a lot different than what we have here. Our heat is very dry and yours is very moist.

[mike_elliott]

20 minutes ago, N201MKTurbo said:

I think humidity has a more detrimental effect than than heat. My old F model sat outside in Arizona for 20 years and I never topped my tanks unless I was going somewhere. That plane had the factory sealant and never leaked a drop.

I have noticed that when I wash out the soap, used to look for leaks, with water, that the sealant changes color. this indicates that it is absorbing water and changing its properties somewhat. It will change back after it dries, but it does indicate that water affects it. How detrimental it is in the long run I don't know.

And #mike_elliott your experience with heat is probably a lot different than what we have here. Our heat is very dry and yours is very moist.

yea, the moist heat is just as bad, judging from what I saw on the ramp at Glendale, and Chandler. Some seriously sick Mooneys aging in the sun, a shame. In any event you point is well taken. Leave it out on the ramp and it will rot. It does in Minnesota, Florida, Indiana (where I have far more wx experience) Arizona or California. UV is destructive no matter where you pay your taxes. Training a guy in Glendale last year we had to start at 4 AM when it was only 104 deg, but it is just as rough training here when it is 92 all day.

Looks like Ill be out that way again in Dec.

[N201MKTurbo]

5 minutes ago, mike_elliott said:

yea, the moist heat is just as bad, judging from what I saw on the ramp at Glendale, and Chandler. Some seriously sick Mooneys aging in the sun, a shame. In any event you point is well taken. Leave it out on the ramp and it will rot. It does in Minnesota, Florida, Indiana (where I have far more wx experience) Arizona or California. UV is destructive no matter where you pay your taxes. Training a guy in Glendale last year we had to start at 4 AM when it was only 104 deg, but it is just as rough training here when it is 92 all day.

Looks like Ill be out that way again in Dec.

I did my ATP check ride at Glendale. I couldn't get the plane in the morning and my check ride started at 2:00. it was 115 outside. It was about 150 in the plane. My IPAD kept shutting down.

It is beautiful here in Dec.

[RobertGary1]

34 minutes ago, N201MKTurbo said:

I did my ATP check ride at Glendale. I couldn't get the plane in the morning and my check ride started at 2:00. it was 115 outside. It was about 150 in the plane. My IPAD kept shutting down.

It is beautiful here in Dec.

I've toyed with the idea of doing my SEL ATP for years but I'm always talked out of it. What made you pull the trigger? I've also heard its hard to find a DPE that has a SEL ATP to do the ride.

 

-Robert

[N201MKTurbo]

1 hour ago, RobertGary1 said:

I've toyed with the idea of doing my SEL ATP for years but I'm always talked out of it. What made you pull the trigger? I've also heard its hard to find a DPE that has a SEL ATP to do the ride.

 

-Robert

I don't have the SEL ATP just the MEL. I pulled the trigger because my friend called in early July of 2014 and said that if I passed my ATP written by the end of the mount I would be grandfathered in until 2016 to get the ATP by the old rules. I told him that I didn't even have a commercial license. He said there are no prerequisites for the ATP written. So I called a testing center and made an appointment for the written on the last day of July 2014. I had 3 weeks to study. Well, I passed it! I now know (well knew) more about crew rest requirements than I ever wanted to know.

Well, we both put off any training till the last minute. In June of 2016 he calls and says he signed up for training and was going to get it. So now I had to do it too (damn him). But I had to get my single commercial, multi commercial and multi ATP in 6 weeks. This included taking the commercial written. DON'T EVER DO THIS!

Well I did it. I was a complete wreck for those 6 weeks. 

Now I'm 10 AMUs in the hole with a real cool piece of plastic to show people! The POS plane I was flying cost $4/min!

 

[Gagarin]

On 10/22/2019 at 10:42 AM, j3gq said:

Paul (weep-no-more) shared this photo with me last night when I asked about such weirdo cases mentioned before. He said this was one of the real messy cases he had to deal with, and his chemicals were up to the job. Sounds convincing, and I don't mean to hold out on you'll when the evidence is contrary to my expressed concerns.

This is one those cases were the F391-53S drain valve would no longer work properly because the bottom drain holes are plugged like the drain holes on the bottom stiffener on the picture. You have to replace the valve with the F391-72. Notice behind the float the drain valve nut plate submerged in sealant. 

Edited November 1, 2019 by Gagarin

[RobertGary1]

18 minutes ago, N201MKTurbo said:

I don't have the SEL ATP just the MEL. I pulled the trigger because my friend called in early July of 2014 and said that if I passed my ATP written by the end of the mount I would be grandfathered in until 2016 to get the ATP by the old rules.

I kind of regret not getting my MEL ATP before the new rules kicked in. If you really get a job that requires an ATP they'll pay for the CTP training but just to have the ticket, its not worth $5,000 for the CTP on top of the regular cost for the rating.

Maybe that's why I've toyed with the SEL ATP. Or Maybe even the SES ATP. I probably am only a few seaplane hours short for that.

-Robert

[Andy95W]

21 minutes ago, Gagarin said:

This is one those cases were the F391-53S drain valve would no longer work properly because the bottom drain holes are plugged like the drain holes on the bottom stiffener on the picture. You have to replace the valve with the F391-72. 

So in your opinion the proper reaction to shoddy maintenance is to use the wrong part.

You gotta be kidding me.

[Gagarin]

1 minute ago, Andy95W said:

So in your opinion the proper reaction to shoddy maintenance is to use the wrong part.

You gotta be kidding me.

The owner of this plane may have no reason to open the tank because there is no leak but low drain stream that he can easily fix with a F391-72 drain valve. The idea here is to show how easily the F391-53S botom drain holes can be plugged.

[N201MKTurbo]

53 minutes ago, RobertGary1 said:

I kind of regret not getting my MEL ATP before the new rules kicked in. If you really get a job that requires an ATP they'll pay for the CTP training but just to have the ticket, its not worth $5,000 for the CTP on top of the regular cost for the rating.

Maybe that's why I've toyed with the SEL ATP. Or Maybe even the SES ATP. I probably am only a few seaplane hours short for that.

-Robert

I've been told that having the ATP is a bit of a disadvantage for getting your first airline job. If you don't have it they will send you for training on their dime. That training is great prep for the sim ride. If you already have it they assume you are good to go and just throw you in the sim.