DIN "Dust Cap" - leaking issues

[docmartin]

have you had issues with the DIN caps letting water into the first stage when soaking your reg? i soaked a DS4 the other day. DIN cap was fully screwed on. when i removed the reg from the bucket and unscrewed the DIN cap there was water on the threads of the first stage. since there are no o-rings in the DIN caps i am wondering if water working its way down the threads was a common issue. it would certainly suck if it got into the first stage. i am a little reluctant now to soak the first stage for extended periods of time.

 

[pants!]

The seal is at the orifice.. the O-ring is on the face of the DIN, preventing water from getting into the reg. The dust cap seals to this O-ring and does a good job of preventing water intrusion.

The threads are not sealed in any way and will get wet. They get wet when you're diving, too.

 

[Marek K]

I got a couple of Aqua Lung DIN caps to replace the worthless rubber mini-caps that came with our Sherwood DIN fittings -- that didn't even reach the threading, and kept falling off.

The Aqua Lung cap has a blind hole in the bottom (top?) of it, into which the orifice fits. The fitting's o-ring then seals against the area outside of the hole. Seems to work, but you obviously have to be real sure the caps are screwed all the way down. Other caps are designed the same way; but it's hard to tell from Internet sites -- you'd have to buy one from a shop in person where you could examine it, or get someone's recommendation.

I don't think there's any real need to soak a first stage extensively. I'd imagine you'd have ambient air pressure inside the first stage as soon as you remove it from the valve; even a few inches/cm of water would cause enough overpressure to start forcing water past the threads, if the cap isn't o-ring sealed. I don't think that would be a problem with a swish lasting a few seconds.

Alternately, an instructor once told me he just puts a finger/thumb over the end of his fitting while swishing it in the rinse water.

*edit for Pants*: Not all DIN caps are designed so that the o-ring seals inside the cap. A lot of inexpesive "delrin caps" aren't -- like the ones with hexagonal heads. Ask me how I know...

--Marek

 

[pants!]

I got a couple of Aqua Lung DIN caps to replace the worthless rubber mini-caps that came with our Sherwood DIN fittings -- that didn't even reach the threading, and kept falling off.

The Aqua Lung cap has a blind hole in the bottom (top?) of it, into which the orifice fits. The fitting's o-ring then seals against the area outside of the hole. Seems to work, but you obviously have to be real sure the caps are screwed all the way down. Other caps are designed the same way; but it's hard to tell from Internet sites -- you'd have to buy one from a shop in person where you could examine it, or get someone's recommendation.

I don't think there's any real need to soak a first stage extensively. I'd imagine you'd have ambient air pressure inside the fist stage as soon as you remove it from the valve; even a few inches/cm of water would cause enough overpressure to start forcing water past the threads, if the cap isn't o-ring sealed. I don't think that would be a problem with a swish lasting a few seconds.

Alternately, an instructor once told me he just puts a finger/thumb over the end of his fitting while swishing it in the rinse water.

*edit for Pants*: Not all DIN caps are designed so that the o-ring seals inside the cap. A lot of inexpesive "delrin caps" aren't -- like the ones with hexagonal heads. Ask me how I know...

--Marek

I'm assuming he is using the Apeks din caps that screw on and make a nice seal.

 

[darkstar]

The deralin caps that I have seal as Pants said, against the face of the DIN fitting.

I still don't 'soak' my Apeks first stage. No point as salt water never enters the first stage. Usually just rinse it under a tap instead.

 

[Marek K]

The deralin caps that I have seal as Pants said, against the face of the DIN fitting.

I've got two other delrin caps that look like this

and have just flat surfaces at the bottoms. The face of the DIN fitting orifice hits that surface, but the o-ring doesn't. The point is that there are bad DIN caps, OK DIN caps, and good DIN caps. Depends what kind Docmartin has.

I still don't 'soak' my Apeks first stage. No point as salt water never enters the first stage. Usually just rinse it under a tap instead.

Agree.

 

[docmartin]

yipeee, i am pretty sure i got the bad kind and it was not cheap. ordered it from diveriteexpress. i'll double check again when i get home. i was wondering how the o-ring on the face of the DIN would seal on a flat surface since it does not really touch the surface. bummer. i guess i'll have to take a look at what the inside of that 1st stage looks like.
the point about the soaking is obviously right. no need to soak a dry sealed 1st stage. i just tend to throw it all in a bucket so the 2nd stage gets a decent soak.

 

[Marek K]

yipeee, i am pretty sure i got the bad kind and it was not cheap. ordered it from diveriteexpress. i'll double check again when i get home. i was wondering how the o-ring on the face of the DIN would seal on a flat surface since it does not really touch the surface.

The DIN caps listed at Dive Rite Express for $8.00 (not that expensive) say they're aluminum, and that they have an "nset designed to fully seal with the regulator DIN fitting preventing moisture from entering." Sounds good... What kind of insert, I wonder?

The cheap caps I have that don't seal are delrin -- plastic!

--Marek

 

[spectrum]

I want to get some screw-on delrin caps because I don't trust the rubber ones ours came with.

For cleaning I mount it on a cylinder and hose it all down while all of the ends soak in a pail of clean fresh water. After a swish and purge I break it down and go get my fills.

Pete

 

[docmartin]

The DIN caps listed at Dive Rite Express for $8.00 (not that expensive) say they're aluminum, and that they have an "nset designed to fully seal with the regulator DIN fitting preventing moisture from entering." Sounds good... What kind of insert, I wonder?

The cheap caps I have that don't seal are delrin -- plastic!

--Marek

the ones i got are delrin, too. they are definitely not like the ones you see on the diveriteexpress website now. btw, the original ones that came with the DS4 were a total joke. they don't even screw on but rather are pliable plastic thingies that you just stick over the thread.