Which LOCKTITE product would you use on your regulator threads?

[scubafanatic]

So, just back from a live aboard trip where due to 'severe panga wave pounding' managed to vibrate loose both a 1-st stage HP swivel joint and a 2-nd stage LP elbow (both failed on same dive just before roll-in, and not during the dive, thankfully.....but that was my guardian angel watching over me!)

I was in one of the world's most remote dive locations (Guanacaste/Bat Islands), FAR from help, MILES from the mothership as some 'panga' rides were high-speed 30 minute 'each way' rides from the mothership, so no way to top off a scuba tank in the event of a gas leak failure as I experienced.

VERY fast crew reaction times thankfully prevented excessive gas loss during the incident, especially from the LP hose blowoff of the 'octo' when they pressurized the tank. The boat averaged 3100 - 3200 fills, I was left with about 2850 psi on that particular dive after tank valve shut down so after re tightening I could still do the dive, otherwise I'd have been screwed as NO refill was possible from the 'panga'.

I won't even go into the ramifications of these twin simultaneous failures had they happened DURING the dive, especially if under deco obligations mid/late dive, under often low/limited visibility, and sometimes high current/surge.

I have now decided to retrofit all my regulators with LOCKTITE, as I feel my guardian angel has given me ample notice.

In 'panga' diving our gear 'lived' on the pange 24/7, so gear inspection between dives wasn't a realistic option, and while on the 'panga' your hands/time were preoccupied hanging on for dear life, not gear fiddling, moreover you can't test/hear for gas leaks with a 140 HP Yamaha outboard motor roaring next to your ear.

So, which LOCKTITE product would you recommend for sealing HP and LP 1-st and 2-nd stage threads ?

Thanks in advance!

 

[Superlyte27]

None, I'd make sure the regs were rebuilt properly using the proper specs in regard to torque.

I own 17 regs. In the last 20 years, not a single one has had the failure you describe. Use a different service tech.

 

[Caveeagle]

I would never use loctite on the hp or LP threads as they are inside the breathing gas side of a reg.

There is one reg manufacturer who had an older service manual that showed using loctite on the DIN inlet threads, but that would be on the ambient side of the reg and should not contact breathing gas. *and that same reg manufacturer told me not to use loctite on their regs now. FWIW

I suspect you have some other issue if your reg hoses are coming loose like this.

 

[DerekR]

Never had it happen, and I've had gear go through a lot tougher pounding than that! Sounds like you were either terrible unlucky, had bad gear, a poorly assembled kit, improperly maintained hoses and/or regulators, or some combination of the above. Those thread don't "just" vibrate loose, even in a severe boat ride.

 

[BoltSnap]

Unless the mfg. says to use locktite (usually the blue version), you shouldn't use it. You must use the appropriate torque, per the respective mfg. to tighten connections on the reg.

 

[scubafanatic]

None, I'd make sure the regs were rebuilt properly using the proper specs in regard to torque.

I own 17 regs. In the last 20 years, not a single one has had the failure you describe. Use a different service tech.

I'll admit I've never been impressed with scuba thread design, with absolutely nothing in place to prevent things from unscrewing, which they actually did under Severe operating conditions. I had a primary LP 2nd stage hose also work itself loose from the 1-st stage on a prior dive which I just happened to catch in it's early stages and tightened that one up before it blew off.

I have reputable dive shops service my gear (Scubatoys), moreover, I'm well versed on removing/swapping hoses and stages on my own, and personally double check ALL connections/fittings pre-trip so it wasn't a torquing failure. (I own 50+ regs)

I do a LOT of DIY custom scuba gear mods/design, and often have to improve deficiencies in the design of off-the-shelf products, so I don't assume scuba gear manufacturers are the sharpest pencil in the box.

I'm now convinced to try the LOCKTITE band-aid to compensate for yet another scuba gear design deficiency, but do appreciate your viewpoint.

 

[scubafanatic]

Unless the mfg. says to use locktite (usually the blue version), you shouldn't use it. You must use the appropriate torque, per the respective mfg. to tighten connections on the reg.

I want to do BOTH, torque AND LOCKTITE. Has anyone seen any reference to a manufacturer prohibiting LOCKTITE usage in this application ?

And thanks for the 'blue' suggestion. I don't plan to weld anything together, which is why I'm asking Which LOCKTITE to get, to allow reasonable disassembly when desired, but provide substantially more grip for secure connection.

------Loctite Threadlocker Blue 242 is designed for the locking and sealing of threaded fasteners which require normal disassembly with standard hand tools. The product cures when confined in the absence of air between close fitting metal surfaces. It protects threads from rust and corrosion and prevents loosening from shock and vibration. Loctite® Threadlocker Blue 242 is particularly suited for applications on less active substrates such as stainless steel and plated surfaces, where disassembly is required for servicing.------

..........."prevents loosening from shock and vibration. .....sounds like just what the doctor ordered!

 

[BoltSnap]

The blue formula (not sure but it maybe no. 240?), won't weld things together, just enough to prevent things coming loose because of vibration. You can still unscrew the connection with blue formula if you have to such as in annual servicing. Although I don't remember now, some mfg. used to require it for securing regulator connections in the past. I don't remember who, what or where now. SP and Atomic don't require it.

 

[scubafanatic]

Never had it happen, and I've had gear go through a lot tougher pounding than that! Sounds like you were either terrible unlucky, had bad gear, a poorly assembled kit, improperly maintained hoses and/or regulators, or some combination of the above. Those thread don't "just" vibrate loose, even in a severe boat ride.

Without starting a debate on it, I'm doubting you had your gear endure anything tougher than what mine endured last week. EVERY panga ride was a severe boat ride, plus many days the mothership towed our pangas (and gear) behind it on the pounding seas during the day and overnight, so our gear spent MANY hours/days getting pounded even when no divers were using the pangas. Poorly assembled kit = NO!, I was certified in 2001, own 50+ reg sets, and own new top-of-the line gear in all categories. My regulator was a brand new Scubapro MK25EVO/S620Ti (personally pool tested for 3 hrs straight 2 weeks prior to my trip.) I'm well versed in adding/subtracting/rearranging hoses and 1st and 2nd stages.

 

[Wookie]

545 is what you want, but man. I'd sure hesitate to use it. It is approved for hoses such as sandblasters breathing air lines, but is NOT approved for anything with enriched quantities of Oxygen.

You know I've run some rough ass trips. Never seen your problem, unless it was caused by improper torquing.