I just got these from a friend, what do all of the markings mean?

[dead dog]

It is probably going to smell like air. The amount of chemical reactions that can occur inside a scuba tank are pretty limited. IF the O2 in the tank reacted with the AL, it would not have a smell. There shouldn't be enough moisture and organic material in the tank for anything to grow. You could probably breath that air just fine even after several years.

One of the attractions of making a scuba tank out of air is that aluminum doesn't oxidize like steel will. a microscopically thin layer of Aluminum oxide forms on the surface of AL and then stops.

The air from the past is better tasting than the air of today.

 

[happy-diver]

“Scrap them!”

So yeah repurposing is king, like the feeling of worth

 

[GiraffeMarineSalvage]

Biggest challenge of spending money on tanks of that era (ie hydro with eddy current test, maybe usable maybe worthless as dive tank...) is comparing that to the cost of a brand new aluminum 80...
Long list of possible reuses with some metal work (if motivated) beyond simply recycling as scrap limited purely by imagination (and "common" sense), short list ranging from a creative mailbox, making book ends, a seasonal solar hot water tank (if painted black and make have over pressure valve), umbrella stand, a tank to store standard air compressor pressure air for tire filling/etc (ie <200psi vs ~3000psi), etc, etc

 

[lexvil]

The bad alloy tanks are nice to have around (once you drill a hole in it) for setting up gear, adjusting things etc.

 

[CT-Rich]

I have seen out inspection tanks of a much more recent vintage (post 2000) going for less than $100. Much less risk. Unless these tanks have sentimental value (mom and dad were wearing them when you were conceived) I would repurpose / recycle them, even the Catalina. Most tank monkeys are going to be told "no AL tanks older than 19**." They were free, so you aren't out anything.

 

[lowwall]

Unless these tanks have sentimental value (mom and dad were wearing them when you were conceived)

My son was conceived on a dive trip, although sadly not on an actual dive. I wanted to name him Reef, but couldn't convince my wife.

 

[Cthippo]

If you are going to dispose of them, I would encourage you to at least donate the Catalina to someone new to the sport who is struggling to afford gear. I have been re recipient of much kindneas on this board and encourage everyone to pay it forward when possible.

 

[GiraffeMarineSalvage]

If you are going to dispose of them, I would encourage you to at least donate the Catalina to someone new to the sport who is struggling to afford gear. I have been re recipient of much kindneas on this board and encourage everyone to pay it forward when possible.

I respectfully disagree, given tank rentals are generally the exact same price (or at worst very close..) as getting a tank fill anyone new to diving is better off simply renting tanks. Paying for a hydro and having the tank not pass would be a bigger bummer to me if I was new to diving and struggling to afford gear...

 

[stretchthepenn]

As other posters have said, the Luxfer tanks are recycling material. I got $15 for one of those. The key is to find a recycler who'll even take them. Many won't because they don't have onsite shredders or don't know the difference between a sealed cylinder that might pop and one that's open to the air...