ports on 1st stage compatible between aqualung/scubapro?

ballastbelly · Jun 22, 2014

can i use a 2nd stage reg (aqualung calypso)
as an octopus on a scubapro mk 2 1st stage ?

when a 1st stage is DIN, does it mean the 4 ports on it follow some sort of common
spec as well, or aqualung & scubapro have their own differing port threading/dimensions

thx
b

Doc · Jun 22, 2014

Dunno 'zackly.... More technical responses forthcoming.

What I do know: After 50+ years of assembling "the dive gear of the day", if you understand how to gently screw the threads into the block of metal, and if they so fit without gnashing of metal... Go forth and SCUBA dive.

Again, there are more complicated and mathematical theories on this. As far as port type and engineered location of placement on any machined first stage manifold, such designs are engineered by domestic felines. There seems to be very little pattern or discernible logic, at least after the LSD wears off if the engineering teams. I'm sure they had a reason for doing what they did on any given First Stage Regulator port placement, but what it may be has always eluded me.

Maybe someone who has taken the Equipment Specialty Class has the historical basis.

herman · Jun 22, 2014

There is no problem using pretty much any second stage with any first. One or the other may need some adjustment but otherwise they will work fine. You may have some difficulty getting both serviced at one place, many shops will not service brands they do not sell.

A "DIN" regulator simply means the design of the interface between the regulator and the tank is a DIN type (German Industrial Standard) as opposed to the yoke ( "A" clamp) type, it has nothing to do with the rest of the reg. Most regs can be had in either configuration, the only difference being a few parts on the input of the reg.

Bob DBF · Jun 22, 2014

What herman said.

Also with DIN, a Din to Yoke adapter is needed for use on tanks without a DIN or convertible valve. This comes in handy if renting tanks, as some rental fleets can have few or no DIN valve tanks available.

Bob
------------------------------
Even a blind pig gets an acorn once in a while.

ballastbelly · Jun 22, 2014

Hi, thanks for all the info on DIN & yoke.

my question was referring more to the ports around the 1st stage, the HP and the LPs .I wish to buy a 1st stage which is compatible
with both aqualung & scubapro regs & guages.

Googling a bit, I found specs about aqualung regs which read
4 Low Pressure Ports 3/8"UNF Thread
1 High Pressure Port 7/16 UNF Thread

and I found something for scubapro mentioning 3/8". brands such as mares & dive rite also mention 3/8".

Is 3/8 the standard for LP and 7/16 for HP on DIN regs? did you ever encounter e clockwise /anticlockwise threads ?
thanks
B

herman · Jun 22, 2014

Again, DIN has nothing to do with the reg itself, just how it connects to the tank. Most regulators since the late 80s use 2 port standards, the HP port(s) are 7/16-20 (UNF) and the low pressure ports are 3/8-24 (UNF). There were a few brands/models that used 1/2-20 low pressure ports in the 80s and early 90s, to my knowledge Scubapro never did. Even if you get one with the 1/2 LP port, the only difference is the hose, adapters are available and inexpensive. Earlier first stages (pre80s) did use a different HP size (it was also 3/8-24) even if you get one of those, there are cheap adapters (<$5) to convert the ports. Bottom, line unless you are getting a pre 90s first stage (or Poiseden) the ports are standard.

ballastbelly · Jun 22, 2014

thanks for the background.
port standardisation is reassuring. nothing worse than having manufacturers disagreeing & using different port sizes .

just curious, but which brand in the 80s started with the 3/8 & 7/16 ports that eventually got adopted as standard?

TotDoc · Jun 22, 2014

Not a problem to use a different brand 1st stage than your second stage, however, I would recommend that both your second stage and your octo are the same brand. Each manufacturer has a certain intermediate pressure that makes their second stages work best, and if you are mixing brands at the second stage level, whatever you set at the first stage may not make 2 different types of second stages happy at the same time.

herman · Jun 22, 2014

TotDoc:
Not a problem to use a different brand 1st stage than your second stage, however, I would recommend that both your second stage and your octo are the same brand. Each manufacturer has a certain intermediate pressure that makes their second stages work best, and if you are mixing brands at the second stage level, whatever you set at the first stage may not make 2 different types of second stages happy at the same time.

As long as the first stage uses an IP in the same general range of IP that 99% of all manuf use (130-145) its not an issue, Posiden is the only real oddball. The first stage is adjusted first and all seconds are adjusted to match it. Second stages are not picky about the exact IP as long as it stays within the 130-145 range IP and it is tuned to that IP. Shops not servicing different brands is the only real issue with mixing brands.

The 3/8 size was used by all manufactures starting in the late 50s. It was originally used for both the HP and LP ports but sometime in the 80s the HP standard shifted to the current 7/16. The 1/2 LP was a marketing gimic used by several brands, I know for sure Dacor and US Dives used 1/2 ports for a while but it never caught on.

Akimbo · Jun 22, 2014

ballastbelly:
…just curious, but which brand in the 80s started with the 3/8 & 7/16 ports that eventually got adopted as standard?

I could easily be wrong but I seem to recall that DEMA (Diving Equipment & Marketing Association) blessed it. The problem was well known because you could accidently screw an LP hose into an HP port and scare the pants off everyone when the hose exploded.

The change took place in a short time window considering rates that new models were introduced and inventory depleted.

ports on 1st stage compatible between aqualung/scubapro?

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