Leaks in oxygen lines and be detected by painting oxygen tubing with
a paintbrush and solution of soap suds--soap bubbles appear at the site
of leak.
Connection of oxygen tubing to nipples, elbows, tees, and regulators
are made air-tight by applying an anti-sieze, sealing compound to the
pipe threads (see note, page 27). DON'T use anything containing OIL.
A good way to check entire oxygen system for a leak is to have
systems charged to 450 pounds the night before take-off. If the pressure
is less than 400 pounds the next morning a leak is present.