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  #1  
Old 04-02-2019, 11:43 AM
romanov's Avatar
romanov romanov is offline
 
Join Date: May 2018
Location: Israel
Posts: 108
Question Testing fuel time with plain water ❓❓❓

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
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  #2  
Old 04-02-2019, 11:45 AM
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Planning initial leak test with water. Think that is the typical method.
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  #3  
Old 04-02-2019, 11:47 AM
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Quote:
Originally Posted by BrianDC View Post
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?
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Old 04-02-2019, 11:59 AM
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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.
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  #5  
Old 04-02-2019, 12:45 PM
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Quote:
Originally Posted by Sam Buchanan View Post
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.
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Old 04-02-2019, 12:46 PM
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Default 100LL

Quote:
Originally Posted by romanov View Post
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.
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Old 04-02-2019, 12:49 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by flyabq View Post
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
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Old 04-02-2019, 01:08 PM
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Question

Quote:
Originally Posted by flyabq View Post
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 ❓
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  #9  
Old 04-02-2019, 01:22 PM
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Default mogas

Quote:
Originally Posted by romanov View Post
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.
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  #10  
Old 04-02-2019, 01:25 PM
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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.
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