I have shared this story before, but here it is with a few more details:
In the early 70’s I was working at Divers Service Center in Puerto Rico (during school break and weekends).
I bought 3 brand new galvanized steel tanks with Scubapro DCAR valves.
The weekend after I got my new tanks my friends and I went camping and diving out of the island of Palominitos just west of Fajardo.
During the weekend we decided to get air from a brand new dive shop that opened in the marina of Puerto Chico (in Fajardo). The dive shop was right on the pier and we were able to dock the two 17 foot Boston Whaler right on front of the fill station. The 17' BW belonged to two of my friends.
We made a line and started passing tanks. I was on the boat at the start of the line.
Before I had a chance to do anything, my new tanks were already hooked up and getting filed. I didn’t like that I didn’t hear any air being bled from the tank or air whip before they got connected, but it was too late, the tank were getting filled. Maybe I just didn’t hear because I was busy.
My new cylinders were the first ones to get filled. After that I made sure to personally connect all the cylinders of my friends.
This was summer time so I went to work on Monday. I decided to open my brand new cylinders and do a VIP, just to check.
All three cylinders had several lines of very bright orange rust from the water drops that were on the whip and maybe the valve and were pushed in during the fill.
I mentioned, this dive shop was on a pier in the marine… they used salt water in their tank filling bath.
I have owned my new cylinders for less than a week and I was tumbling them. I owned the cylinders for many years after that, but that nice shiny interior of a brand new cylinder was gone after the tumbling.