Here is something I learned today about DIN plugs

[BrackaFish]

You mean nitrox? Explain?

Also, do the pressure relief ones stop any accidental valve opening leaks? (Like from little kids on the loose.)

Just as I personal choice I don’t use any type of plug and have not had any issues. As far as rug rats, when they were little my oldest boy cracked open one of my tanks to scare the crap out of his younger brother. When I found out, I scared the crap out of both of them. They both Dive now so they don’t do that stuff anymore.......mostly

 

[Divin'Papaw]

I use them in all my valves and have for years. I no longer tech dive but when I did I did NOT use them on rich deco mixes. They have saved me from gas loss on multiple occasions. They do get bumped somewhat regularly and end up pressurized. A properly sized crescent wrench which I always have with me takes care of it with 3-4 slow partial turns. The plastic/delrin ones are worthless and can be downright dangerous if pressurized.

 

[happy-diver]

On my few easy roll on valves usually when recently rebuilt with a new seat before the ocean has had
a chance to seize them up to a satisfactory level or when paranoia rears it's ugly head I tape the knob

 

[martincohn]

Oh you mean the spare o-ring holder!

 

[Bigbella]

The all metal plugs are great. The plastic ones are decorative. That said one must always have a wrench to remove said plugs. Nothing worse than getting to the dive site and not being able to remove it because of the pressure. Guess how I know ???

Oh and yes the o-rings do have a habit of coming off inside the valve. One does learn to check for that too.

Not from just pressure -- electrolysis as well. I had a few cylinders in storage and discovered that the metal plugs, presumably, aluminum, had seized to the valves. It took some channel locks and colorful language to remove them.

I have used vented delrin plugs ever since, without any issue . . .

 

[TrimixToo]

Here's what's wrong with the Delrin plugs. If they get pressurized they become projectiles.

And, yes, it frickin' *hurt*.

 

[pauldw]

And, yes, it frickin' *hurt*.

You should not do that again.

 

[Umuntu]

I have Delrin plugs with a tiny vent hole. It keeps out dust, and delrin avoids galvanic corrosion that sometimes occurs with metal plugs with a different metal to the valve body.

I'd also rather lose a little gas than run the risks of a pressurized plug.

 

[TrimixToo]

I have Delrin plugs with a tiny vent hole. It keeps out dust, and delrin avoids galvanic corrosion that sometimes occurs with metal plugs with a different metal to the valve body.

I'd also rather lose a little gas than run the risks of a pressurized plug.

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

 

[doctormike]

I have Delrin plugs with a tiny vent hole. It keeps out dust, and delrin avoids galvanic corrosion that sometimes occurs with metal plugs with a different metal to the valve body.

I'd also rather lose a little gas than run the risks of a pressurized plug.

So why use them at all? Why not just leave the DIN valve open?

I mean, I guess if you are going to store tanks for a long time in a dusty environment, you could put a bit of masking tape over the hole. But these plugs seems like a solution in search of a problem. I have dealt with a lot of DIN tanks over the years, never had a problem with dust.