Cracked second stage

[Paladin]

I just got a USD Aqualung Conshelf SE. The first stage is in excellent, like new condition and has recently been serviced. The second stage was also serviced, but I've noticed four hairline cracks in the plastic where the LP hose fitting screws in. It isn't leaking under pressure (yet) and I'm wondering if there is a way to reinforce the plastic before it has a chance to get worse.

This is my first plastic reg. I have avoided them like the plague and I got this one only because it came with the first stage. I do not plan to use it as a primary, but it might make a good octo if the fitting can be reinforced.

 

[emoreira]

Hi, Paladin, post a pic of the crack, so we can make recomendations. I would suggest to use Cyanoacrylate glue with a stainless steel insert to reinforce, but if the crack is in the thread, it could be difficult to repair, and you should replace the part.

 

[redacted]

Sounds like the metal inlet fitting was overtightened in the plastic case. Easily occurs if 2 wrenches are not used when the hose is tightened. The good news is it is not exposed to any pressure, but you do have to watch for a vacuum leak to develop.

I'd be tempted to clean up the case real good, lube the threads on the inlet fitting and install it, and then apply some adhesive to the visible cracks (I'm guessing superglue but maybe someone will have a better idea). It is just a matter of time before those cracks grow and leak but that time could be hours or decades.

 

[LeadTurn_SD]

My guess (like awap said) is that the cracks will eventually "travel". I've had some luck "stopping" hairline cracks on fiberglass surfskis and boats by drilling a small hole at the end of the crack, then using epoxy or fiberglass and resin.... neither of these is probably approriate for a plastic reg.... I think awap may have the best solution....

But if it were me.... I'd probably just replace it. I think knowing it was cracked (even hairline) would bother me, even on an octo.

You've got a nice first stage, maybe look on ebay for a lightly used 2nd stage??

Or, contact couv here in the regulator section... he had expressed some interest in selling some of his restored excess Scubapro R-109 balanced adjustable 2nds, which would be a nice match with your Conshelf 1st

Bets wishes.

 

[Fishpie]

The plastic USD 2nd stages (especially the yellow ones) had a known problem with cracks where the LP seat assembly was pressed into the plastic housing.
Chances are that it has been that way for more than 20 years and the crack(s) are not growing.
USD offered a free replacement case for a while......you might be able to find a well established AquaLung dealer that still has a case or two knocking around in a forgotten corner....it was a very common problem.

 

[Fishpie]

double post

 

[Hallmac]

Divers Equipment and Repair in Kansas City Missouri still has a case of replacement bodies in stock. They can fix you up.

 

[Paladin]

Well,
I put super glue on the cracks and the glue wicked into the cracks. I let the glue cure and it looks like it's going to hold. While I was at it, I disassembled all our Conshelfs (3 XIs, a XII, an SE and a 22), three of the Aquarius' (the ones we use as backup regs) and all our extra USD 2nds (all metal) and serviced them. The plastic 2nd that cam with the SE can be replaced with with one of the all metal 2nds if necessary, but I kind of like the looks of the SE 2nd as an octo.

Hallmac: I'll check into getting a replacement body or two just in case. Thanks.

 

[knowone]

Such beautifully moulded plastic seconds so smooth inside and the weighted exhaust T is a sight to behold. Design, ported and polished.

There is mucho gratificacion to be had with older irreplaceable plastic in finding a non performance or non asthetic area and filing or sanding off some stock to mix with cyanoacrylate to create a mush to smear into cracks that have been created and remain open by the corroded chromed brass bits they are encapsulating.
After a good vibrating of course.
But vinegar sucks the juice out of plastic.
When cured work surface to match surrounding surface and there is less of that ugly white chalky residue crap to scrape off too.
Of course there may be some clamping and extra batches of mush to contend with.

NO. I think it's a drop or two of thinner mixed with plastic filings.

Current same design rubbish copies regs stay cracked or can be smeared with gloop in but better for parts because everything fits something else.

Super glue works on sound rubber good too but more on rubber and rubber productions when it arises.

 

[captain]

Just buy a metal Conshelf or Calypso 2nd off ebay, better and probably cheaper than a new plastic housing.