New to DIN tanks- need advice

[Gren]

Dust cap for the first stage

https://www.divegearexpress.com/regulators/regacc.shtml

Stainless HP plug for the tank valve if you feel it necessary or just dust plug

https://www.divegearexpress.com/gas/cylacc.shtml

 

[claymore]

I have plugs in all my DIN regs unless they have the yoke insert in. I have had a couple of occasions where the tank valve got rolled a little bit and would have let gas escape from the valve, not fun when you are on a two or three day dive trip and no fill stations around. Went to unscrew the the plugs and they would not budge. Turned off the gas and got a big wrench to unscrew the plugs.

 

[flspy]

I have plugs in all my DIN regs unless they have the yoke insert in. I have had a couple of occasions where the tank valve got rolled a little bit and would have let gas escape from the valve, not fun when you are on a two or three day dive trip and no fill stations around. Went to unscrew the the plugs and they would not budge. Turned off the gas and got a big wrench to unscrew the plugs.

You mention both regs and tank valves. My reg has a rubber cap.

Are you saying the tank leaked and the plug in the DIN fitting got jammed from the pressure- the same way you can't unscrew a yoke valve when the tank valve is open?

A lot of people are recommending the plugs to keep the gas from leaking out if the valve gets accidentally opened. But the same would happen with a yoke valve, correct?

 

[kelemvor]

My DIN tank caps have a small hole in the middle where a string attaches. They're not air tight. No risk of getting stuck pressurized, however something fell on my tanks in the garage once and I lost about 2000psi from a full bottle. I guess that's still preferable to having a pressurized cap stuck on the tank. The only reason I use tank caps is so I can tell which of my tanks should be full at a glance. Empty or partials get no cap. Fulls get a cap. When I've got a bunch of tanks in the back of the car (some full, some empty) it makes things easier.

My regulator caps which look like the $3 ones Gren linked are water tight. They screw on securely and are a blessing when cleaning your reg. I had a rubber push on cap come off when dunking a reg post dive. Resulted in an early trip in for service.

I have inadvertently cross threaded a din reg into a tank. At least, I assume that was the cause of the problem. Removing the reg from the tank took a pipe wrench. No permanent damage, but if it hadn't happened after my last dive of the day I might have missed some diving.

 

[Dr. Lecter]

Derlin/plastic DIN plugs: Pro: will not corrode in the valve no matter how long it's left there. Cons: will not protect valve from deformation, will not retain gas if valve rolls on, worse than useless unless having a hole preventing pressurization, as sudden high pressure plus unrelieved plastic DIN plug can result in high velocity plastic shrapnel.

Chrome-plated brass DIN plugs: Pros: should not corrode in the valve no matter how long it's left there, add a DIN o-ring to it and it will seal in gas if valve rolls on, will provide some protection from deformation if the valve is struck. Cons: will not protect against deformation as well as SS, and is probably too soft to fix mild/moderate deformation, will need a decent wrench to remove if it seals in gas.

SS DIN plugs: Pros: excellent protection of the valve against deformation, and in a pinch may "un-egg" a mildly dented valve if wrenched in and seated completely, add a DIN o-ring to it and it will seal in gas if valve rolls on. Cons: SS and chromed brass will eventually gall the plug into the valve if left long enough, and warm/humid/salt makes the reaction happen faster, will need a decent wrench to remove if it seals in gas, cost a quarter to a half as much as the valve they're in.

Personally, I think the Gulftex or Highland SS plugs are the best, and I just make sure I have an adjustable wrench around if I need to undo a pressurized one. NBD, and I've never seen doing so hurt the threads. Keep extra DIN orings around for them, though, as they tend to get ripped up through the bleed hole when you unscrew the plug.

Brass plugs are theoretically better at avoiding galling, but I've yet to have a problem with SS plugs...then again, I've only left them in for a few weeks/maybe a few months, without removing them. The derlin/plastic plugs are just junk IMO. Without a hole, they're dangerous; with a hole, they're useless at keeping out water/dirt. YMMV.

For DIN regs, I say the delin Highland screw-on DIN caps are the best and even those are not 100% reliable for soaking. The rubber caps like Atomic ships with their DIN regs are for dust, not water of any amount.

 

[flspy]

Derlin/plastic DIN plugs: Pro: will not corrode in the valve no matter how long it's left there. Cons: will not protect valve from deformation, will not retain gas if valve rolls on, worse than useless unless having a hole preventing pressurization, as sudden high pressure plus unrelieved plastic DIN plug can result in high velocity plastic shrapnel.

Chrome-plated brass DIN plugs: Pros: should not corrode in the valve no matter how long it's left there, add a DIN o-ring to it and it will seal in gas if valve rolls on, will provide some protection from deformation if the valve is struck. Cons: will not protect against deformation as well as SS, and is probably too soft to fix mild/moderate deformation, will need a decent wrench to remove if it seals in gas.

SS DIN plugs: Pros: excellent protection of the valve against deformation, and in a pinch may "un-egg" a mildly dented valve if wrenched in and seated completely, add a DIN o-ring to it and it will seal in gas if valve rolls on. Cons: SS and chromed brass will eventually gall the plug into the valve if left long enough, and warm/humid/salt makes the reaction happen faster, will need a decent wrench to remove if it seals in gas, cost a quarter to a half as much as the valve they're in.

Personally, I think the Gulftex or Highland SS plugs are the best, and I just make sure I have an adjustable wrench around if I need to undo a pressurized one. NBD, and I've never seen doing so hurt the threads. Keep extra DIN orings around for them, though, as they tend to get ripped up through the bleed hole when you unscrew the plug.

Brass plugs are theoretically better at avoiding galling, but I've yet to have a problem with SS plugs...then again, I've only left them in for a few weeks/maybe a few months, without removing them. The derlin/plastic plugs are just junk IMO. Without a hole, they're dangerous; with a hole, they're useless at keeping out water/dirt. YMMV.

For DIN regs, I say the delin Highland screw-on DIN caps are the best and even those are not 100% reliable for soaking. The rubber caps like Atomic ships with their DIN regs are for dust, not water of any amount.

Thanks for posting. I was wondering about my Atomic DIN Cap.