Steel tank and rust

[Luis H]

It's called purging. Following an inspection, pump the tank to 200 psi with dry gas and empty. Refill to rated pressure with dry gas and this problem, however rare, will not occur.

That is a very good idea.

I have been pre-warming my tanks before I open them (and keep them warm until I close them to make sure no moisture will condense on any surface), plus I flush the inside with dry air just before I reinstall the valve. It seems to work well, but I will add your technique since it is easy and it can only help.

Thanks

 

[spectrum]

Essentially the same thing they do when you fill a virgin propane tank. Dilute the ambient to a tiny minority or what remains in the cylinder. It makes you wonder why it's not already SOP.