Small pieces of plastic coming out of 2nd stage

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aoumi

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Location
South Pacific
Hi,

This afternoon I was checking the IP of my first stage with an IP gauge attached to my BCD hose, and also tuning a different 2nd stage that I had recently overhauled. I had attached an extra hose to my standard reg setup (Scubapro MK21, S560 primary, and S360 Octo, with a Tusa SPG) so that it had 5 hoses coming off it. (Primary and secondary second stages, BCD hose, SPG, and one extra hose which I was tuning the overhauled 2nd stage with, a G250V). So basically just attached the overhauled reg to my standard setup in order to tune it.

Tuning went fine, but, after I had finished, grabbed my primary first stage (S560 of my standard setup, not the overhauled one I was tuning), and purged it a couple of times with it pointed into my hand. Some small pieces of plastic shot out.

My first thought was, did I clean/rinse this since my last dive? They look a little like large-ish salt crystals, and were clear. So purged again. More small pieces of plastic came out.

Checked and it wasn't salt, it was indeed small bits of clear, soft plastic, with the occasional small black piece. Purged again, no more came out.

I remembered I had rinsed, soaked and cleaned my regs after my last dive (which was back in October last year), as I always do.

I then recalled the myflex hose problem that I read about. The only myflex hose I have is an Aqualung BCD inflator hose, the rest are all standard hoses (Scubapro hoses x2 with a Tusa SPG and hose - all these are the standard non-myflex Scubapro/Tusa hoses).

Could there be any other cause of this problem other than a Myflex hose delaminating? Bug/insect damage inside the primary 2nd? (Although the diaphragm and exhaust valve looks fine, so other than those, I don't know what could be damaged).

During the overhauled 2nd stage tuning, I was turning the tank valve on and off a large number of times while I tried to tune the G250V 2nd stage orifice position, so the system was being pressurised and de-pressurised a lot.

I had the myflex hose with IP gauge attached perched up on my speaker a little higher than the first stage, with the first stage angled slightly down so that the primary and octo hoses were pointing down, while the myflex BCD hose and overhauled 2nd hoses were pointing slightly up. If it is the myflex hose, I am guessing that when de-pressurising and purging the system, the air in the hose emptied back into the first stage, and bits of plastic 'fell' down to where the primary 2nd stage hose is?? And when purging the primary 2nd again when the system was pressurised, blew the rubbish into the primary 2nd stage. Just a theory.....

The other alternative is that something in the 2nd or 1st stage has somehow degraded??? Or the Scubapro hose has the de-laminating problem, but it is not myflex.

Since then, I have disconnected the hose from the S560 primary 2nd stage (nothing inside the air barrel before the orifice), and nothing coming out of the other end of the hose where it connects to the first stage.

I also disconnected the Aqualung Myflex hose from the 1st stage, and as I did so, 1 only very small piece of the plastic substance came out as I pulled the hose out of the first stage, but it wasen't obvious if it fell out of the first stage or the hose.

But now, if I look in the bottom of the primary second stage (S560), through the clear exhaust valve using a torch, I can see more of the plastic particles sitting in the bottom of the second stage, and even a piece on the inside of the exhaust valve itself. But I am wondering how none of this collected in the hose side of the orifice.

I was planning an overseas trip away in a few days and was packing, but looks like this reg setup is now staying at home. And if the Myflex hose blew plastic back into the first stage as well, then an expensive overhaul maybe required to get rid of the plastic stuff?

Any ideas what this could be? The plastic is quite soft, not hard. Images attached...

20180421_172848.jpg
20180421_172337.jpg
20180421_172302.jpg
20180421_172213.jpg
 
Took the Diaphragm cover off - it has been eaten......

Looks like not a Myflex or hose problem after all. Apologies for the thread. Sure looked like myflex hose delamination tho.

Now investing in some bug-proof sealable plastic containers....

20180421_195501.jpg
 
Debris shown doesn't seem to match the compound used in the diaghram.

Try removing the 2nd stage and seeing what comes out of the hose....

The crystallization issue wasn't exclusive to older miflex hoses... it was any hose that had a specific material for the inner lining. Miflex design hoses merely concealed that issue because the middle layer prevented obvious symptoms of a breached inner layer. Other hoses could do the same... although rubber 2-layer hoses would usually bulge or bubble at the first sign of a inner hose leak.
 
Yeah, it doesn't look like diaphragm material. OTH, pieces look to big to come through orifice. Pull all of your second stages off and open the valve and see what happens.
 
@DevonDiver What do crystallized pieces of Miflex designed hose feel like? Are they hard/semi hard or soft?

@aoumi same question except related to the pieces you found coming from your regulators.

TIA
 
Hi,

This afternoon I was checking the IP of my first stage with an IP gauge attached to my BCD hose, and also tuning a different 2nd stage that I had recently overhauled. I had attached an extra hose to my standard reg setup (Scubapro MK21, S560 primary, and S360 Octo, with a Tusa SPG) so that it had 5 hoses coming off it. (Primary and secondary second stages, BCD hose, SPG, and one extra hose which I was tuning the overhauled 2nd stage with, a G250V). So basically just attached the overhauled reg to my standard setup in order to tune it.

Tuning went fine, but, after I had finished, grabbed my primary first stage (S560 of my standard setup, not the overhauled one I was tuning), and purged it a couple of times with it pointed into my hand. Some small pieces of plastic shot out.

My first thought was, did I clean/rinse this since my last dive? They look a little like large-ish salt crystals, and were clear. So purged again. More small pieces of plastic came out.

Checked and it wasn't salt, it was indeed small bits of clear, soft plastic, with the occasional small black piece. Purged again, no more came out.

I remembered I had rinsed, soaked and cleaned my regs after my last dive (which was back in October last year), as I always do.

I then recalled the myflex hose problem that I read about. The only myflex hose I have is an Aqualung BCD inflator hose, the rest are all standard hoses (Scubapro hoses x2 with a Tusa SPG and hose - all these are the standard non-myflex Scubapro/Tusa hoses).

Could there be any other cause of this problem other than a Myflex hose delaminating? Bug/insect damage inside the primary 2nd? (Although the diaphragm and exhaust valve looks fine, so other than those, I don't know what could be damaged).

During the overhauled 2nd stage tuning, I was turning the tank valve on and off a large number of times while I tried to tune the G250V 2nd stage orifice position, so the system was being pressurised and de-pressurised a lot.

I had the myflex hose with IP gauge attached perched up on my speaker a little higher than the first stage, with the first stage angled slightly down so that the primary and octo hoses were pointing down, while the myflex BCD hose and overhauled 2nd hoses were pointing slightly up. If it is the myflex hose, I am guessing that when de-pressurising and purging the system, the air in the hose emptied back into the first stage, and bits of plastic 'fell' down to where the primary 2nd stage hose is?? And when purging the primary 2nd again when the system was pressurised, blew the rubbish into the primary 2nd stage. Just a theory.....

The other alternative is that something in the 2nd or 1st stage has somehow degraded??? Or the Scubapro hose has the de-laminating problem, but it is not myflex.

Since then, I have disconnected the hose from the S560 primary 2nd stage (nothing inside the air barrel before the orifice), and nothing coming out of the other end of the hose where it connects to the first stage.

I also disconnected the Aqualung Myflex hose from the 1st stage, and as I did so, 1 only very small piece of the plastic substance came out as I pulled the hose out of the first stage, but it wasen't obvious if it fell out of the first stage or the hose.

But now, if I look in the bottom of the primary second stage (S560), through the clear exhaust valve using a torch, I can see more of the plastic particles sitting in the bottom of the second stage, and even a piece on the inside of the exhaust valve itself. But I am wondering how none of this collected in the hose side of the orifice.

I was planning an overseas trip away in a few days and was packing, but looks like this reg setup is now staying at home. And if the Myflex hose blew plastic back into the first stage as well, then an expensive overhaul maybe required to get rid of the plastic stuff?

Any ideas what this could be? The plastic is quite soft, not hard. Images attached...

View attachment 456082 View attachment 456083 View attachment 456084 View attachment 456085

Hoses are cheap. I would cut the hose open and inspect the interior of it. It looks like the pieces come from that second stage though.
 
@DevonDiver What do crystallized pieces of Miflex designed hose feel like? Are they hard/semi hard or soft?

Hard to describe... they vary, I think. Could be down to temperature. Small translucent or yellowish crystalline-type chunks, but they aren't brittle, they tear.

Screenshot_2018-04-22-01-24-51.png


If you've had the hoses for more than a couple of years they are probably due a change anyway - dissect one and see what the state of the inner layer is.
 
What kind of bug eats a diaphragm?
 
a love bug.
 

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