Scubapro naming convention?

[Angelo Farina]

Awesome, that actually helps a lot. Am I correct in understanding that the MK25 is actually a worse choice for cold water than the MK17?

Both MK17 and MK25 are regulators greatly engineered for cold water.
The difference is not low water temperature, they both withstand it very well.
The point is water cleanliness: the MK17 (or the MK19, equipped with a rotating turret similar to MK25) is a diaphragm reg.
And it has a sealed diaphragm covering. Hence no water comes inside: you can dive in muddy or silty water without problems.
Instead the MK25 is a balanced piston, offering higher flow and better pressure stability. But water penetrates inside, and if there is mud or silt this can cause damage to the piston's dynamic O-rings, or, even worse, to the mating metal surfaces.

The only fully sealed SP piston reg has been the MK10, which is my favourite one. With its proper SPEC rubber boot, the internal chamber is fully packed with silicon grease. This provides full protection both against ice and against dirty water...
SP does not make it anymore, but the design of the MK10 has been replicated in Atomic first stages.

 

[BoltSnap]

@Angelo Farina I am waiting for the "F" first stage

 

[Angelo Farina]

@Angelo Farina I am waiting for the "F" first stage

Well, I contributed very marginally to the development of the 109.
In spring 1978 I did carry my modified 109 to the SP factory in Casarza Ligure, showing them my modification.
I did cover the metal disc embedded in the center of the diaphragm with a thin layer of low friction plastic, reducing the friction of the contact between the stainless steel lever and the metal disk.
The technicians appreciated the mod, in fact the following year the new diaphragm was released with a low friction plastic disk instead of the metal one.
I was not paid for this (I was 17), but I received a gift pack containing some SP items: a torch, an SOS decompressimeter (bend-o-matic), two repair kits for my two regs (including the new diaphragms), a gym suit, two T-shirts and a woolen cap.

 

[BoltSnap]

I was not paid for this (I was 17), but I received a gift pack containing some SP items: a torch, an SOS decompressimeter (bend-o-matic), two repair kits for my two regs (including the new diaphragms), a gym suit, two T-shirts and a woolen cap.

That was so cheap of them!!

 

[Bigbella]

I try to give a short answer.

Angelo, I couldn't quite catch that. Could you repeat it? heh, heh, heh . . .

 

[Open Ocean Diver]

Scubapro vintage timeline.

Thank you Kevin

 

[shoredivr]

Both MK17 and MK25 are regulators greatly engineered for cold water.
The difference is not low water temperature, they both withstand it very well.
The point is water cleanliness: the MK17 (or the MK19, equipped with a rotating turret similar to MK25) is a diaphragm reg.
And it has a sealed diaphragm covering. Hence no water comes inside: you can dive in muddy or silty water without problems.
Instead the MK25 is a balanced piston, offering higher flow and better pressure stability. But water penetrates inside, and if there is mud or silt this can cause damage to the piston's dynamic O-rings, or, even worse, to the mating metal surfaces.

The only fully sealed SP piston reg has been the MK10, which is my favourite one. With its proper SPEC rubber boot, the internal chamber is fully packed with silicon grease. This provides full protection both against ice and against dirty water...
SP does not make it anymore, but the design of the MK10 has been replicated in Atomic first stages.

To me, the MK25 is not a good idea: most of the water in shore diving around here has silt and mud. Ridiculous design. I have one and I don’t know why I bought it. Should have gone for the MK17.

 

[halocline]

Both MK17 and MK25 are regulators greatly engineered for cold water.

I wouldn't agree with this assessment. The MK25 does work ok in very cold water, but it is hardly 'greatly engineered' for cold water. It is not sealed, but there are some coatings and plastic bushings added to reduce or prevent ice build up. Given the fact that a very similar type of regulator, the atomic 1st stage, as well as earlier SP 1st stages (MK5/10) can be fully sealed with either PTFE or silicone grease, the MK25 is comparatively not well designed for cold water. Again, there have been many thousands of successful dives in cold water with the MK25, but if someone is buying a regulator specifically for very cold water, the MK17 is a much better choice, as is any fully sealed 1st stage.

 

[Pressurehead]

chromed brass (108, 109, 129, 156). The first is obsolete, the other 3 are my favourite ones. They can be all fitted with the balanced S-wing poppet of the G250, converting them in second stages that are almost the best you can buy, despite having been built 40+ years ago.

Fantastic, I will resurrect my old 109.
Thanks, I have a Scubapro and old Aqua Lung Calypso reg obsession, all work and I have the spare parts for 1st and 2nd Stages.

 

[Open Ocean Diver]

Be careful they can be very addictive.

View attachment 617091

Beautiful trio Kevin thanks for sharing.