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Why it's a good idea to wash your gear in fresh water

Posted: Tue Sep 12, 2017 6:33 pm
by ScubaLawyer
Found floating off Dana Point, CA. :shock:
Tank 1.jpg
Tank 2.jpg

Re: Why it's a good idea to wash your gear in fresh water

Posted: Tue Sep 12, 2017 9:54 pm
by luis
Does it have air?

My LDS had an aluminum cylinder that a local fishing vessel brought aboard on its net. It was full (or close to full), but it wasn't going to be for long. The walls were heavily pitted. It was impressive that it hadn't started leaking or let go yet.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Tue Sep 12, 2017 10:19 pm
by ScubaLawyer
luis wrote:Does it have air?.
No clue. Didn't check it. Got donated to my LDS

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 13, 2017 12:01 am
by kworkman

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 13, 2017 11:16 am
by swimjim
One of the reasons I love Lake Michigan. Fresh water. I was on a dive boat about ten years ago. The captain saw something on the sonar and stopped to have a diver check it out. The mark turned out to be nothing, but embedded in the lake bottom was a AL 80 with an old style back pack on it. It must have fallen off a boat a few years before. The tank still had air in it. The diver cleaned up the tank and it passed hydro and went back into use!

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 13, 2017 7:57 pm
by crimediver
I would be scared that could be an explosion waiting to happen. I would drill a very small hole through the burst disk to vent it and see what it does...

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 13, 2017 11:01 pm
by luis
crimediver wrote:I would be scared that could be an explosion waiting to happen. I would drill a very small hole through the burst disk to vent it and see what it does...
I like that idea.

The smaller the hole the better, but just to give some reference of the pressure thrust (force) on the small drill bit.

An 1/8” (0.125”) hole has an area of 0.01227 inches squared.
Multiply by 3000 psi and you have a pressure force of 36.8 pounds.

An 1/16” (0.0625” ) hole has an area of 0.00307 inches squared.
Multiply by 3000 psi and you have a pressure force of 9.2 pounds.

The head of the burst disk screw has no pressure load. The actual thin disc may let go, but the head of the screw should control gas escaping.

You should never drill (even a very small hole) on the actual wall of the pressure vessel. The hole could become the trigger to a structural failure.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Thu Sep 14, 2017 6:59 am
by Herman
How about drilling a .308 hole......from 100 yards away? A 30-06 should do nicely. :)

Re: Why it's a good idea to wash your gear in fresh water

Posted: Thu Sep 14, 2017 9:06 am
by simonbeans
Herman wrote:How about drilling a .308 hole......from 100 yards away? A 30-06 should do nicely. :)
It worked for Chief Martin Brody.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Thu Sep 14, 2017 8:37 pm
by georgeaustin
When you get the o ring out from under the valve, let me know - I need one

Re: Why it's a good idea to wash your gear in fresh water

Posted: Fri Sep 15, 2017 4:05 pm
by hunterkz
I would have eaten those scallops before I got rid of it. I like the 308 diameter hole idea too.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Sat Dec 02, 2017 1:21 pm
by Nemrod
Y'all quit funnin' with my tank, it just needs a little cleaning It will be okay, I think. Hard to get the bands around it though.

My drill bit would be a .45 caliber, go big or go home.

N

Re: Why it's a good idea to wash your gear in fresh water

Posted: Mon Sep 16, 2019 6:19 pm
by SnarkIII
A guy I work with gave me 3 old aluminum tanks, all old bad alloy. One of them the valve is frozen so I cant confirm the tank is empty. Is drilling through the safety disc the safest way to ensure nobody (myself included) gets hurt with this tank? Does anyone have a safer method? Saving the tank and or valve are low concern.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 18, 2019 7:01 pm
by Vancetp
Nemrod wrote:
Sat Dec 02, 2017 1:21 pm
Y'all quit funnin' with my tank, it just needs a little cleaning It will be okay, I think. Hard to get the bands around it though.

My drill bit would be a .45 caliber, go big or go home.

N
I once let a young lady try out my Mosin Nagant sniper rifle. She was shooting at one of those swing type targets with cast metal circles that hang from a rod. You hit it and it spins around the rod. This one had 6"-5"-4"-3"-2" targets. Out to about 1000 feet, the only thing she hit was the 5/8" rod, putting a 2/3 complete, perfect hole through it. 7.62x54r (.308-ish) FMJ. That'd release the pressure on any tank. Or go through an engine block.

Re: Why it's a good idea to wash your gear in fresh water

Posted: Wed Sep 18, 2019 8:07 pm
by h2operations
I saw the end results of someone who made an IED but forgot the trigger/fuse. They thought drilling into it would work........ It worked really well.......

He probably never heard the explosion.