Here is something I learned today about DIN plugs

[HKGuns]

I use Delrin plugs on my tanks and they don't have O-Rings. I figure it is more than enough to keep them dry and clean while not in use.

 

[Storker]

My DIN tank valves have either a regulator or a dust cap in them at all times.

My DIN tank valves have either a regulator in them or a tape across them. Unless they're empty, in which case they're wide open.

Never had an issue for eight years. I used to have Delrin caps on my valves, it turned out to be too much of a hassle. I still have them stacked away somewhere, just can't remember where.

 

[W W Meixner]

Both of my tanks have DIN plugs, which I got after losing some air from slightly rolling the valve while one of them was in the back seat. I recently spun off both plugs, to check air pressure on the tanks, Then I put a reg on one of the tanks. Glancing at the plugs on the table top before heading out to dive I noticed that they didn’t look the same. Indeed one had an O-ring and the other did not. So I proceeded to search for the missing O ring, and it had fallen off inside the back of a tank valve. So, my own lesson is, pay attention to things.

Here's one of those plugs, in case it's unclear what I was talking about:
View attachment 588482

Paul...

You may want to use the DIN plugs that are shown in the attached photo...made from Delrin/drilled...and this ''O'' ring won't get lost inside the valve...

If you find yourself ''wrench-less'' you will not be able to remove your sealed plug if you have an accidental valve release...secondly you may end up with ''dis-similar'' metal corrosion which will seize the plug in place...resulting in damaged valve threads...

You can still rinse your cylinders without worry...have done so for years...a quick on/off of the valve before installing your regs just to be sure...

W...

 

[W W Meixner]

That picture above? That Delrin DIN plug had a tiny vent hole.

TMT...

Bet that hurt in the morning...never had that problem...all my plugs are drilled with a large enough hole to allow the double hang cord to pass freely...

If it should get ''plugged'' and you have pressure backed up behind it...the fact that you can't unscrew it would be your first sign...the best property of Delrin is that it is ''self lubricating and will not seize...

I look at these plugs more as a protection of the valve threads and not for protection against ''dust''...

The hardcore guys usually do not use plugs of any kind...seemingly with no problem...far be it from me to argue with that...

W...

 

[Diving Dubai]

I would suggest a piece of masking tape as a safer solution.

Been there, done that. Masking tape lasts less than a month before it hardens - Duct tape just becomes a sticky mess

But I'm not going to be defensive about delrin plugs its a personal choice.

 

[Storker]

Been there, done that. Masking tape lasts less than a month before it hardens - Duct tape just becomes a sticky mess

But I'm not going to be defensive about delrin plugs its a personal choice.

Masking tape, painter's tape or electrical tape, it's all just to show that the tank is full.

If your tank is stored full for more than a month, you don't dive often enough.

 

[Diving Dubai]

Masking tape, painter's tape or electrical tape, it's all just to show that the tank is full.

If your tank is stored full for more than a month, you don't dive often enough.

I have a total of 36 tanks & I'm pretty sure I dive more (qty and frequency) than you

 

[Storker]

I'm pretty sure I dive more (qty and frequency) than you

You probably do. I'm not going into a d*** measuring contest; I have better things to do.

 

[flymolo]

I use the steel (unvented) plugs on tanks that have trimix in them. It beats that "oh sh!t" moment you have when you bump a valve and hear gas hissing out or worse, when it happens inexplicably while driving, forcing me to pull over on the side of a road or highway. I take extra care when wrenching them off should they become pressurized, however.

 

[bletso]

A big reason to use a DIN plug is to protect the valve. I have had two valves deformed from mishandling or falling over just right. There is not much meat in the top of a DIN valve and once deformed they are toast! I really don't worry about gas loss as it can happen just as easily with a yoke valve! Now with an expensive trimix a metal plug can be a savior.