Leaking Wing Tank

[jacksonshaw]

I have a very slow leak in the Wing Tank of my J3. It does not appear to be at the fuel outlet or bottom drain. I have heard that there is a sloshing fluid you put in the tank, bounce the wing up and down at the wing tip then drain. does anyone have any input on this? I hate to open up the fabric ,take out the tank etc., if there is any other way.
Jackson

 

[will767]

 

[longwinglover]

 

[Patrick]

 

[Denton]

 

[jacksonshaw]