I have been thinking about potential leaks after closing the rear baffle. I have been thinking that I will try to test for leaks on the tank without the rear baffle installed. My idea is to take some plastic and wrap it around the back where the baffle is suppose to go and seal it temporarily with duct tape to create a seal and then pump up the tank with air. I figure if there is a leak, it will show up and it would be easier to fix before the baffle goes on. After any leaks get fixed on the main tank, then the baffle is put on and final leak test is done. Anyone try this before?
Van's Air Force
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Before Closing the Fuel Tanks?
- Thread starter Naruto
- Start date
Let us know if it works
Good luck...sounds like a fine idea to try. You might find it difficult to maintain a seal with duct tape...even at 1 psi. Since I just spent several weeks chasing baffle leaks on my left tank, I might try your idea on the right...providing it works - Be sure to let us know!!
Good luck...sounds like a fine idea to try. You might find it difficult to maintain a seal with duct tape...even at 1 psi. Since I just spent several weeks chasing baffle leaks on my left tank, I might try your idea on the right...providing it works - Be sure to let us know!!
Kyle Boatright
Well Known Member
Back in the day, I sat my tanks (sans rear baffle) leading edge down, installed the caps, taped off the vents and fuel lines, and filled 'em with water.
I kept 'em that way for a couple of days to make sure there were no obvious leaks. Fortunately, there were none, nor have the tanks leaked in the 6.5 years the airplane has been flying.
Testing with water will show most leaks, but not all, because gasoline molecules are smaller than water molecules.
I kept 'em that way for a couple of days to make sure there were no obvious leaks. Fortunately, there were none, nor have the tanks leaked in the 6.5 years the airplane has been flying.
Testing with water will show most leaks, but not all, because gasoline molecules are smaller than water molecules.
Flying Scotsman
Well Known Member
Hmmmm...is that true?
H2O is a pretty small molecule compared to hydrocarbon chains, I'd think...
H2O is a pretty small molecule compared to hydrocarbon chains, I'd think...
I think it might have more to do with surface tension than actual molecule size.
And if you're believin' THAT, I got this bridge you might be interested in.
dbuds2
Well Known Member
Another Water question
Has anyone filled a completed tank with water? I haven't prosealed the sending unit and it's plate yet, so I would remove, clean/dry and lube the sending unit after the water test. Already fixed one little leak at the baffle to end rib corner. It just feels like the full of liquid test would be very representative of when it's on the wing with fuel.
Has anyone filled a completed tank with water? I haven't prosealed the sending unit and it's plate yet, so I would remove, clean/dry and lube the sending unit after the water test. Already fixed one little leak at the baffle to end rib corner. It just feels like the full of liquid test would be very representative of when it's on the wing with fuel.
Kyle Boatright
Well Known Member
Anything is possible, but I think pressurizing a taped up tank will be a real challenge. Additionally, you can't apply much pressure (maybe one PSI) before you get some serious deformation of the tank IF you could get it to seal with tape.
I don't have a tank handy, but if the top surface is 4' long and 2' wide, that's 8 square feet x 144 square inches = over 1100 in^2 At one PSI, there would be over 1100 pounds of force trying to pull that tank apart. Not a good idea!
LettersFromFlyoverCountry
Well Known Member
It seems to me -- a conclusion based solely on anecdotal evidence -- that most leaks in tanks are at the baffle rather than the rivets.
I always think of something George Orndorff drilled into us in his fine video. "If you look in the tank and say 'that can't leak,' it probably won't. But if you look in and say, 'i don't THINK that is going to leak,' you need more ProSeal.
I think I used a whole can on one tank. But I saved most for the baffle. You know, if you put a goodly amount on there, and then look inside where the ProSeal accumulates as a bead at the intersection of the skin and the baffle, you'll see exactly what he meant.
I always think of something George Orndorff drilled into us in his fine video. "If you look in the tank and say 'that can't leak,' it probably won't. But if you look in and say, 'i don't THINK that is going to leak,' you need more ProSeal.
I think I used a whole can on one tank. But I saved most for the baffle. You know, if you put a goodly amount on there, and then look inside where the ProSeal accumulates as a bead at the intersection of the skin and the baffle, you'll see exactly what he meant.
wingtime
Well Known Member
YUP! I belive Bob is right most leaks happen at the rear baffle. If you have a good blob of proseal on top of each shop head the tank the rivets shouldn't leak. Other common areas for leaks are the nose and rear corners of the end ribs. The only leaks I had were on the rear baffle to skin rivets. It turns out the bead of proseal Van's suggests to seal the rear baffle is way to small. Butter that sucker up so you know it wont leak!
