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[PabloPicasso]

A gas bubbler is a safety device that allows in line easy leak checks. It fits between the flexible gas hose after the regulator and the copper pipework. You press a button on top and it bubbles if there is a gas leak. No bubbles if installation is sound

What about tek7 as a glue? I've never tried it but it is a water proof sealant and glue

 

[Easticks28]

Excuse my ignorance but what is a gas bubbler and why is it on your boat?

Splendid piece of kit - it's a leak detector for gas systems.
http://www.gasproducts.co.uk/acatalog/Marine_Gas_Leak_Testers__Bubble_etc_.html