Testing fuel time with plain water ❓❓❓

[romanov]

Fellow builders,

I have sealed the tanks and still
dont have real fuel liquid close by.

Can I test the tanks with just watter?
How accurate is that testing?
Is it possible that watter won't leak
and 100LL later will.



Thanks a lot
Roman

[BrianDC]

Planning initial leak test with water. Think that is the typical method.

[romanov]

Originally Posted by BrianDC

Planning initial leak test with water. Think that is the typical method.

Sure, no bad in the initial try. But should I go
on and insist on real 100LL test?

[Sam Buchanan]

Why not test it with air? Put a couple of PSI in the tank and spray the outside with soapy water, any leaks will cause bubbles to form.

[romanov]

Originally Posted by Sam Buchanan

Why not test it with air? Put a couple of PSI in the tank and spray the outside with soapy water, any leaks will cause bubbles to form.

The back buffle is not riveted yet. I want to
be sure before I seal it completelly.

[flyabq]

Originally Posted by romanov

Sure, no bad in the initial try. But should I go
on and insist on real 100LL test?

Yes, Water has a much higher surface tension than 100LL. While it might not leak with water it doesn't mean that it is still 100% leak proof. You would be much safer to do the final test with either properly regulated air or 100LL.

The initial test with Water should be fine to test for larger leaks. If there are any of descent size then water will still leak.

[lr172]

Originally Posted by flyabq

Yes, Water has a much higher surface tension than 100LL. While it might not leak with water it doesn't mean that it is still 100% leak proof. You would be much safer to do the final test with either properly regulated air or 100LL.

The initial test with Water should be fine to test for larger leaks. If there are any of descent size then water will still leak.

+1

Without pressure, solvents, such as gasoline, can easily weep through spaces that water cannot, due to the lower surface tension.

Larry

[romanov]

Originally Posted by flyabq

Yes, Water has a much higher surface tension than 100LL. While it might not leak with water it doesn't mean that it is still 100% leak proof. You would be much safer to do the final test with either properly regulated air or 100LL.

The initial test with Water should be fine to test for larger leaks. If there are any of descent size then water will still leak.

Ok second question: is 95 octan as good as 100LL
for real tank testing ❓

[flyabq]

Originally Posted by romanov

Ok second question: is 95 octan as good as 100LL
for real tank testing ❓

I have never flown with MoGas. I am not sure what the surface tension is. If you are flying with MoGas checking with that should not be an issue. If you are I would use non Ethanol for testing purposes.

[lr172]

The gas is the same. 100LL just adds lead and some other additives to it and leaves out some additives found in auto gas. Surface tension of all gasoline is pretty much the same, as is it's viscosity.