1ST Stage ?

[domino22]

Which is the best way to go on a first stage ? 1) Piston (or) 2) Diaphragm? And why? Thanks

 

[ElectricZombie]

For general, basic diving, either will do fine.

Diaphrams are perceived as being better for cold water diving, they are less likely to freeze up. The inner workings are sealed inside the reg, and protected from the water. You don't have to do anything special to these.

Some pistons regs can be equipped with a cold water kit that will allow it to function without freezeups at low temperatures. Without the kit, the inside of the reg is exposed to cold or freezing water, and can malfunction. Add the cold water kit and the problem goes away.

Pistons usually perform a little better than diaphrams, but not enough to really notice.

All my regs are piston. If I ever decide to start ice diving, I'll convert them for cold water or just buy all new diaphram regs if I'm feeling lazy.

 

[domino22]

Thanks I ordered a scuba pro mk25 last night with the 380 octo and a pair of fins.They called today and told me the fin color was not in stock and this was good because I also found out it was comming overnight, and I don't need it till april I thought I asked for ups ground ,do not know what happened? It was thru lp and even though I have not got it yet I liked the phone call from them. If all else works well I will use them again!

 

[Diver0001]

domino22 once bubbled...
Which is the best way to go on a first stage ? 1) Piston (or) 2) Diaphragm? And why? Thanks

I'll go along with what ElectricZombie said but I'll add this:

Some piston regs are environmentally sealed and they work just fine in cold water. The Sherwood 1sts are well known as excellent cold water regs and it's a piston design. The secret is the dry-bleed system. I've used mine in water as cold as -2C without problems. (I use my Sherwood for my octopus, my main reg is a Aqualung LX supreme - diaphragm).

Pistons that are open to the environment shouldn't really be used in cold water if you ask me. Having said that, 99% of the freeze-ups I've ever seen hvae been 2nd stage freeze-ups. Don't neglect this detail when choosing a cold water reg.

As for performance, both designs work and there are good and bad examples of both. The 2nd stage has a bigger influence on the work of breathing.

And finally, many pistons are mechanically simpler than diaphragms. This has lead some people to claim that pistons are more reliable. However, I don't have the impression that either design is prone to failure and the difference (if there is one) is most likely insignificant either way.

R..

 

[Warren_L]

Is there much of a difference in the cost and ease of serviceability of piston regs versus diaphram regs? I gather the diaphram regs are a bit more expensive to buy, and servicing and parts (well, at least parts) are probably more expensive too.

 

[emeyer36]

I can answer some of your question from recent experience. I just bought my new regs, the Scubapro mk25/s600. Scubapro's lower priced first stages (i.e. the mk16) are diaphram and their top of the line high-proformance (the mk25) is piston. The opposite may be true of some companies and I think at least one company I looked at offers only diaphram. I bought my reg through my LDS, who was willing to give me a good deal, so I got the Scubapro warranty which provides parts for the annual servicing as long as I own the reg. My cost is only the tech fee. For this warranty I was willing to pay a little bit more than internet pricing, but not full MSRP. My family and I have a very good relationship with this LDS, since all 4 of us dive and give them most of our business.

In researching regs, I saw and was also told that diaphrams are more expensive servicing-wise, and not that much better use-wise, except in the extremes already mentioned. Those extremes are why manufacturers started to develop the different types of cold protection for the piston first stages.

emeyer36

 

[Lead_carrier]

wlo93 once bubbled...
Is there much of a difference in the cost and ease of serviceability of piston regs versus diaphram regs? I gather the diaphram regs are a bit more expensive to buy, and servicing and parts (well, at least parts) are probably more expensive too.

If you have a warranty then the parts should be free. As to the cost of service, IMHO it should cost the same. I charge the same price, piston or diaphram, even tho the diaphram is a bit more difficult to service. ie. more parts. Check with whoever will be doing your service if you have any questions.

 

[Warren_L]

Thanks for the information. I think I'm probably going to go diaphram. Depending on which one I go with, price shouldn't be too much more as well as with the servicing. Plus living in Canada it would be nice to have something for ice diving... my PADI instructor was trying to sell me on that last week.