Fix the IP of a s/pro mk2 1st- how?

[Woz]

Well it says it all in the title. I have a number of "spare" regs knocking about and the mk2 1st is the simplest thing this side of a brick. Anyone fixed the IP on this before?

[Digger]

I have a plug for a DS4/T. Get yourself one of them you tightwad. You probably already have about half a dozen. Use the MK2 as bailout, you're never going to use it anyway

[Woz]

Give us the plug, then, Digs. Already have a DST to whop it on mind you I'd like to leave it for my OC stuff and it would need a good clean too.

[Digger]

Use the standard method for O2 cleaning and you'll be fine. I'll trade the plug for stuff I need. Not sure who owes who what any more, but it felt like we were back to level again last time we spoke. At least if the Frog wing turns up ever we might be!

I'll have that ally plate off you if it's not a POS.

Digs.

[fatone]

You add shims to change the I.P. each shim is approx. 5 psi.

[Woz]

Originally Posted by fatone

You add shims to change the I.P. each shim is approx. 5 psi.

*sigh* not the answer to my question. I don't want to change it- I know how to do that- I want to fix it. So it won't increase when I go deeper.

Although apparently Rick Stanton has been to 180m with a non-fixed O2 reg and a needle valve.

Silly boy.

[Jetsam]

Originally Posted by Woz

*sigh* not the answer to my question. I don't want to change it- I know how to do that- I want to fix it. So it won't increase when I go deeper.

Although apparently Rick Stanton has been to 180m with a non-fixed O2 reg and a needle valve.

Silly boy.

Set to your required IP ( I presume 8.5-9.5 bar ) then weld the ambient pressure holes shut!

But I suspect this is not the answer you are looking for

[Woz]

Originally Posted by Jetsam

Set to your required IP ( I presume 8.5-9.5 bar ) then weld the ambient pressure holes shut!

But I suspect this is not the answer you are looking for

Then it would leak through the thread on the bottom of the cap.

I might make a new cap with an O ring and no holes. Or might not.

[scubacoach]

Scubapro did make a MK2 that had a fixed IP for use as a SASY unit Surface air supply, that fitted to a jacket with buoyancy floats in. Designed for a product in the US not sure if it came to Europe, this was about five six years ago.

[NotDeadYet]

Originally Posted by Woz

*sigh* not the answer to my question. I don't want to change it- I know how to do that- I want to fix it. So it won't increase when I go deeper.

Although apparently Rick Stanton has been to 180m with a non-fixed O2 reg and a needle valve.

Silly boy.

You only need to fix the IP if you are using a fixed orifice valve like the KISS or Hydrogom valves. I've used needle valves with non-fixed IP's on both my homebuilds and my KISS.

Using it allows the KISS to be used beyond the maximum depth rating which would be equal to the IP of the 1st stage. There is a finite limit that the IP can be cranked up to, the DST spring doesn't like higher IP's than about 12bar. And the higher the IP then the smaller the orifice needed. Small orifices become really unreliable (and hard to source) because they have a bigger reaction to contamination.