Are metal Din Plugs and Caps overrated? Where do you put em'?

[Bob01]

Hey All,

From reading a few threads about DIN caps n' plugs - it seems every loves the stainless plugs & aluminum caps, however with metal caps I would assume there is a chance of them getting stuck to the valves or regulators after a saltwater dive from electrolysis?

For a diver that doesn't dive with expensive gases (nitrox at the most), dives primarily in saltwater and doesn't foresee his valves getting damaged/not hard on my equipment - Plastic or Delrin caps would be the best choice?

For Din plugs and caps, do you have them attached to your tank/regulator (like those who dive with yoke)? If you do, do you have trouble getting all the water off them before reattaching them?

Thanks,

Bob

[Gombessa]

I have the stainless steel DIN plugs, and I loved 'em, but after a while I just stopped using them.

They can be beneficial in preventing loss of gas (they have o-ring DIN seals), but if you accidentally charge the cylinder with the plugs installed, you'll need a big wrench to turn it free.

They can also potentially prevent a DIN valve from deforming in the event the tank is dropped upside down onto the valve, but that's a fairly remote risk IMO.

If the plugs are machined poorly (as some of the ones I've had were), they can chew up the threads on the valve, especially if charged. The Gulftex and XS Scuba plugs are machined quite well and don't have that problem.

Finally, XS Scuba makes an unforgivably stupid and ill-conceived version of their DIN plug, with a sharp channel carved through the threads. It's supposed to prevent the plugs from locking onto the valve with an accidental charge, but it makes no sense since the channel doesn't reach the o-ring; instead it can act as a tap and completely mangle your DIN threads if you have to crank it off on accidental charge.

Again, after several dozen dives, I just gave up on the plugs and tape over the valve openings after fills.

[mksmith713]

Metal DIN plug are a must in my opinion.
I had a tank fall over and hit directly on the valve with a plastic plug in it and the valve deformed to the point where the reg no longer fits into it.
Though I haven't had any tanks fall over with the metal plug, I do know folks who have and said the metal plug saved them.
As far as first stage caps....I have tried both and prefer plastic for the reason you stated.
I had metal originally and had a problem with corrosion from salt water causing it to become stiff and difficult to remove.

[deepdvr1]

You could get the gas savers with pressure release. They wont mess up your valve when you accidentally charge the cylinder with plugs installed.

Cylinders & Accesories - Gas saver with pressure release stainless steel - ScubaSupport.nl

I never dive with plugs from the regulators or valves attached. Its just one more thing that can snag on something during the dive, and you dont have to worry about getting them dry after the dive either.

[rjack321]

Either use the stainless plugs or leave the valve holes open. If you pressurize the valve with a plastic DIN plug in there - say from accidentally turning the knob while carrying the tank... Insufficient gas comes out the "vent" hole and the plastic bits can/will explode out of the valve. More than one person has been to the ER for hand reconstruction because of these stupid plastic things.

Plastic caps on regulators are a good idea and allow you to throw the whole thing in a bucket to soak.

[Peter_C]

Plastic caps on regulators are a good idea and allow you to throw the whole thing in a bucket to soak.

That would be assuming it has the relief so the end of the din fittings o-ring can seal. Not all do.

I use the stainless tank plugs. Lets me know which tanks are filled and which ones still need to be topped up. I have too many tanks around to keep track of fills. Plus I figure if I to have a valve roll on, it won't drain my tank. I have had one roll on in the back of my car and had to pull over and resolve the issue. In the back of a p/u truck that might have been discovered at the dive site by an empty tank.

Where do you get the pressure release plugs in the USA? Those look really nice. Wonder how hard it would be to modify mine? Hmmm...

[fdog]

+1 for the SS DIN plugs - they've saved my valves from damage many times. And given the cost of Helium nowadays, they've saved me some serious $ as well.

Getting them off is really no big deal: apply a wrench, turn slowly, and after two turns or so, they drain nicely. I have never sustained any damage to the threads from doing this.

As for the DIN cap for your regulator, you've been given spot-on advice to avoid the metal ones. They will corrode to the reg and be darn near impossible to remove. Get the delrin models.


All the best, James

[Bob01]

Thanks everyone for your replies!

So I wont be "upgrading" my din caps on my regs, and wont be getting plastic or delrin plugs for the tanks for fear of having a piece of shrapnel blown through my palm ... prob wont go down the stainless steel plug route either because I know the day some air escapes, I wont have my wrench with me :-p

How about those flexible covers similar to those on yoke tank valves? Just looking for something to protect the threads/keep crap out

[tregrrr]

I have just rubber formed into a hollow plug shaped dust cap that sits in the the din hole. it does not engage the threads so does not build any pressure (it just pops out with anything more than a nitrox testing flow rate) and will not shoot anyone.

while it offers ZERO protection to gas loss or valve physical damage, it does keep dust out.

[boulderjohn]

Here is a use for a steel plug you may not have considered.

I had a tank fall while it had a regulator on it. We were able to get the regulator off with the help of a wrench, and it was OK. The manifold valve, on the other hand, was distorted and could not be used. On a whim, we hand screwed in a SS pug as far as it would go and then finished it off with a wrench. It fixed the valve beautifully.