Servicing my own gear

[Tbar]

Looking for opinions and advice here. After a long conversation with the boss, she told me I should service our own regs and other gear. I did service on regs many moons ago and am familiar with the general process, but looking to get some specifics. I will be purchasing the test equipment needed and an ultra-sonic cleaner. I figure I'll be into the test gear and tools at somewhere between $1000-1500. Considering that we drop about $400 every time we have our stuff serviced, it should pay for itself after the 3rd time.

What I'd like to know from you guys that service your own regs, what test equipment and tools do you recommend? I have and Atomic Aquatics B2 and my wife has a SP G250 with a Mk25. Also have AIRII's on our BC's. Also, best source for parts?

Here is my list of tools of the top of my head:

• Scubapro Multi-Tool, Brass Chrome http://www.scubatools.com/p-457-scubapro-multi-tool-brass-chrome.aspx
• Scubapro Piston Bullet, Brass http://www.scubatools.com/p-470-scubapro-piston-bullet-brass.aspx
• Scubapro Mk20/Mk25 Assembly Tool http://www.scubatools.com/p-475-scubapro-mk20mk25-assembly-tool.aspx
• O'ring Pick Set, 5 Pcs. & Storage Tube http://www.scubatools.com/p-397-oring-pick-set-5-pcs-storage-tube.aspx
• First Stage Handle, Heavy Duty, Brass http://www.scubatools.com/p-464-first-stage-handle-heavy-duty-brass.aspx
• 1" Yoke Nut Socket http://www.scubatools.com/p-476-1-yoke-nut-socket.aspx
• Dual Drive Inline Adjusting Tool (without gauge) http://www.scubatools.com/p-540-dual-drive-inline-adjusting-tool-gauge-sold-separate.aspx
• 3" x 3/8 Drive Extension http://www.scubatools.com/p-477-3-x-38-drive-extension.aspx
• Torque wrench
• Allan keys
• Small shifter spanners
• Appropriate sockets
• Appropriate screw drivers
• Quality IP gauge
• Ultra-sonic cleaner
• Vice/Bench/workspace

I have a number of genuine service kits, but tend to use generic O-rings and parts. For the first stage MK25 I will only use the kit if I need to replace the HP Piston bushings, generally I don't. But I have been lucky to pick-up about 50 MK25 seats. My seconds are s600 and most parts are generic, including the mushroom seat. The kits have new knob stickers and face pins and housing clips, these can all be re-used if removed carefully.

Attached is a Scubapro o-ring chart, linking the SP part number to generic O-rings. Also the number required for servicing the MK25 band S600 variants.

I have gone for only one brand/model of reg to help with parts and servicing. I have 9 sets.

 

[guruboy]

Which models do you use the Piston Bullet with?

 

[bl6394]

@awap - I looked closely at that composite piston assembly. The shoulder has flats machined into it that one could put a tool on. And the back of the piston stem has a notch. If one had a cone shaped tool with a corresponding key - you could try to turn that shoulder on / off. That's how it is assembled. But - if you look in the hole on the side of that shoulder - you can see that the stem threads are coated with a red thread-locking compound... I doubt that assembly is ever going to come apart...

I'm not thrilled about it. I usually use the Mk 25 on a bailout bottle. Which usually has something less than 40%. But because I might use it on a mix of up to 100% - I've O2 cleaned it and installed the Nitrox kit with the O2 safe seat. But I'm not thrilled with the idea of O2 cleaning that piston assembly by just throwing it in the ultrasound. I've been told the captured o'ring wont by affected - but there are lots of crevices that contaminates could be trapped in - making O2 cleaning that assembly dodgy... I suppose it's only going to be exposed to O2 at IP - so perhaps it would just smolder if contaminated? Or would one just replace it at every O2 cleaning? (~ $30)... Not ideal.

Anyway - interesting point you raised about that part...

Thanks,

 

[redacted]

I used a pick to scrape away the red locktite, cleaning out that small hole. Then I used a wrench on the flats and an easy out in the air passage on the piston head. Came apart quite easily. As I recall, I used an 013 duro 70 o-ring.and reapplied locktite after tightening. It cured the leak from the ambient chamber that I had encountered.

 

[tbone1004]

if only exposed to IP, I wouldn't be terribly concerned. Hell I have never O2 cleaned any of my second stages and most people that I know don't. In the first stage I'd send it through the ultrasonic with Simple Green and maybe give it an extra cycle, but should be OK otherwise

 

[halocline]

Which models do you use the Piston Bullet with?

You have to use them with the Mk5/10/15. They have sharp edges on the piston shaft. The MK20/25 has a rounded piston, it's not necessary to use the bullet. But, it might make installing the piston a little easier. You have to use a bushing installation tool that has a hole bored for the piston bullet, otherwise you can't hold the bushings in place while installing the piston with a bullet.

The rounded edge is obvious, it doesn't take anything like magnification to see. It's clearly designed to seal differently than the knife edge pistons.

I think there was a period of time when SP was not telling techs to use the bullet on the MK20/25, but they seem to have changed that advice. So, if you have the right bushing tool, you can use a bullet on any of the balanced piston models.

 

[halocline]

The Rene in previous comments was, Rene Dupre, Technical Manager at Scubapro. He's responsible for teaching the equipment repair courses for Scubapro and seems extremely knowledgeable about the Scubapro product line and techniques used for servicing them. The weekend class Halocline referred to was a hands on two day seminar describing the processes for servicing Scubapro regulators and is consistent with the manufacturer's present expectations for servicing their products. Halocline seems to take exception with some aspects of their course content.

I have no exception with Rene or the course content. I do feel that a weekend seminar that nobody has ever failed (and for which the only entrance requirement is dive shop sponsorship) is not sufficient on its own to qualify someone as a professional technician. So when I ask you a question about a particular aspect of regulator function and your only answer is "Rene said so...." then I have to wonder if you really understand what I'm asking about. For example, I asked why it would be necessary to check IP on a newly serviced regulator at 500 PSI first. Your answer was "to establish IP at 500 PSI" or something along those lines. That's not really an answer about why you think it's necessary. I know that it's not, from experience. If you have an actual answer for that, I'd be interested.

I also asked about calling the MK17 "overbalanced" and your only answer was "Rene called it that." But it's not "overbalanced" it's actually acting more as an unbalanced diaphragm reg. You don't seem to understand why that is, but if I'm wrong, please feel free to explain it.

Many of us on this DIY forum got our start at least in part due to the incompetent work by dive shop technicians, who are all graduates of the same weekend seminar you took. Over the years I've listened to a lot of nonsense from supposed professional dive shop techs, so I ask your forgiveness if I seem a little combative to you. I appreciate your participation on this forum, but I'm always wary of 'professionals' who tout their credentials while providing not really insightful (or sometimes simply wrong) information about regulator function.

 

[guruboy]

Is that tool different than the Mk20/25 white plastic looking piston assembly tool?

Didn't think there was room for the bullet in that.

You have to use them with the Mk5/10/15. They have sharp edges on the piston shaft. The MK20/25 has a rounded piston, it's not necessary to use the bullet. But, it might make installing the piston a little easier. You have to use a bushing installation tool that has a hole bored for the piston bullet, otherwise you can't hold the bushings in place while installing the piston with a bullet.

The rounded edge is obvious, it doesn't take anything like magnification to see. It's clearly designed to seal differently than the knife edge pistons.

I think there was a period of time when SP was not telling techs to use the bullet on the MK20/25, but they seem to have changed that advice. So, if you have the right bushing tool, you can use a bullet on any of the balanced piston models.

 

[redacted]

Is that tool different than the Mk20/25 white plastic looking piston assembly tool?

Didn't think there was room for the bullet in that.

My Mk20 assembly tool is black finished metal. It predates the Mk25. The hollow center is deep enough to fit both the bullet tool and the shaft of the composite piston. So, by adding the bullet tool, the HP o-ring may be pushed back into place by the bullet taper if it was dislodged during installation or the turn of the assembly tool. Much to my surprise, it could not be used in that manner with the older brass piston which was in use when I obtained the tool. That older piston has a smaller diameter bore and will not fit the bullet tool.

 

[bl6394]

... For example, I asked why it would be necessary to check IP on a newly serviced regulator at 500 PSI first. Your answer was "to establish IP at 500 PSI" or something along those lines. That's not really an answer about why you think it's necessary. I know that it's not, from experience. If you have an actual answer for that, I'd be interested.

From a professional repair technician's perspective - the simplest answer is "It's necessary because it's part of the manufacturers prescribed procedure for servicing this model of regulator."

Liability in the SCUBA industry is - in part - mitigated by following industry standards. When teaching - this means that I comply with my agency's standards - and when things end unfavorably as they sometimes do despite our best intentions - my agency - and more importantly my insurance carrier stand behind me. With respect to regulator service, complying with the manufacturer's training requirements, recommended tools, techniques, service kits, and procedures mitigates the risk of servicing a piece of equipment that may be involved in someone's unfavorable ending. While I may be sued - my insurer's attorney will reasonably argue to a jury that by properly servicing the regulator in the manner prescribed by the manufacture - I was not negligent or liable for the injured party's outcome. If however, I deviate from the manufacturer's procedure - or make up my own process, or substitute alternative parts when servicing a regulator - then my attorney has a much more difficult task explaining why I may or may not be liable for an outcome.

Perhaps risk mitigation or liability isn't something you concern yourself with. From a purely functional perspective, Scubapro's engineers have established (or at least they publish) that the optimal range of IP most favorable for their line of second stages is: 125 - 145 psi. For balanced regulators with an IP inversion - verifying that the IP is near the high end of the range at low supply pressure generally results in a regulator tuned in a manner consistent with their engineering recommendations. E.g. [IP 145 @ SP 500 ... IP 140 @ SP 3000] As the inversion is variable and not always present - starting with a low SP is an efficient way to establish an optimum IP - within the manufacturers specification. I don't see a more efficient procedure for doing this. Without know the amount of inversion to expect - it would be necessary to guess the optimal IP at SP 3000 PSI - and ensure that the IP stayed within the prescribed range when SP pressure was dropped to 500psi.

I suppose you could be asking any number of other questions... Why does Scubapro prescribe an optimal IP range of 125 to 145psi. Why did they choose to manufacture a balanced regulator (the Mk 25) who's IP may experience inversion of 1 to 5 psi over the typical range of supply pressures. What processes in the first stage contribute to this effect. Couldn't I service this regulator in an alternative fashion and improve its performance beyond the manufacturer's expectations? None of these questions are interesting to me - for reasons related to liability. And frankly - I don't know how any of this benefits the DIYer who is wondering what their IP on their Mk25 should be tuned to after servicing - and how they should go about doing so. Frankly, it starts to feel like...

Many of us on this DIY forum got our start at least in part due to the incompetent work by dive shop technicians, who are all graduates of the same weekend seminar you took. Over the years I've listened to a lot of nonsense from supposed professional dive shop techs, so I ask your forgiveness if I seem a little combative to you. I appreciate your participation on this forum, but I'm always wary of 'professionals' who tout their credentials while providing not really insightful (or sometimes simply wrong) information about regulator function.

I don't take you personally. We've all experienced professionals whose execution left us disappointed. I've been disappointed by some of the scuba professionals I've encountered. I'm happy to participate in the forum with the understanding that any recommendations or opinions publicly shared will generally be consistent with those of the manufacturer.

Personally - my interest in regulator / gear service is mostly from self-interest. I sometimes enjoy doing solo technical dives. Sometimes in overhead environments. Sometimes on CCR. Sometimes both. While training for failures is important - my likelihood of a favorable outcome is in part proportional to to the reliability of my gear. I'm passionate about having my gear performing optimally - and I'm happy to share that enthusiasm with others.