scr bailout from mccr

RonMicjan · 7th October 2006, 17:22

Quote: (Originally Posted by robertfondren)

I have no means of monitoring the pO2 YET!

dude, with all due respect, if you dive this rig without PO2 monitoring, you are a fool. There are at least 10 ways to set this up for reasonable dollars and off the shelf parts. If you cant do it yourself, go buy a sport kiss or get in the que for a COPIS meg and take the course. Hey, its only your heartbeat that you are screwing with.

under no circumstances should you dive this rig with air diluent and SCR. SCR rebreathers are designed to use 32% or higher nitrox, thereby giving bag PO2's a bit lower after you metabolise some O2.

***EBT*** · 8th October 2006, 11:10

Quote: (Originally Posted by robertfondren)

Allright, full disclosure. What i've done is taken an ida72d2, replaced the dsv with one from an ida59, removed the O2 injection system, and replaced this with a normal second stage with the exhaust ports blocked. At this juncture, the only gas I have available is air. What I believe it is capable of doing is: 1. Giving me 4 breaths to each vent at the surface, 2.Giving me twenty breaths per vent at 132 feet. I have no means of monitoring the pO2 YET! The second I have my scrubber filled properly, I intend to test these beliefs. I will not be alone, and if a Mod1 class for converted ida72d2' s were offered, I would of course be the first in line.

Now that my dirty little secret is out, is anybody still willing to talk to me, or have we already reserved a space in the memorials? LOL

Whoa!

Good on you for asking before you did anything.... Im hoping the drivel Im about to spill out isnt teaching you to suck eggs....

SCR's in concept are meant to be operated with Nitrox (or trimix), never air. Why? Two reasons why air is a poor choice of drive gas;

1. You'll drop the Po2 quickly.
2. You end up with a breathing mix that is MORE narcotic than air alone.

If you're deep enough to be able to utilise the low PO2's the (1) generates, you're deep enough that you dont want to be narced.

If you've not already discovered it, Ake larsson's site is a good reference.

This thread also has some useful calculations, although Im not sure how relevant they are for you, since you dont mention what your addition/venting technique is.

I'd suggest reading up very carefully about addition/venting techniques, since there are VERY few SCR units out there that I'd trust to operate without a PO2 monitor. I certainly wouldnt run manual like this....

Good luck, be safe!

robertfondren · 10th October 2006, 03:50

All of you are right. Input appreciated.

7th October 2006, 17:22	#11 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,100	Re: scr bailout from mccr Quote: (Originally Posted by robertfondren) I have no means of monitoring the pO2 YET! dude, with all due respect, if you dive this rig without PO2 monitoring, you are a fool. There are at least 10 ways to set this up for reasonable dollars and off the shelf parts. If you cant do it yourself, go buy a sport kiss or get in the que for a COPIS meg and take the course. Hey, its only your heartbeat that you are screwing with. under no circumstances should you dive this rig with air diluent and SCR. SCR rebreathers are designed to use 32% or higher nitrox, thereby giving bag PO2's a bit lower after you metabolise some O2. __________________ Marine rescue, towing and salvage. Interfering with natural selection since 1983. www.tmishop.com Diving bits etc. www.seatowpdx.com The Summer Job
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8th October 2006, 11:10	#12 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,969	Re: scr bailout from mccr Quote: (Originally Posted by robertfondren) Allright, full disclosure. What i've done is taken an ida72d2, replaced the dsv with one from an ida59, removed the O2 injection system, and replaced this with a normal second stage with the exhaust ports blocked. At this juncture, the only gas I have available is air. What I believe it is capable of doing is: 1. Giving me 4 breaths to each vent at the surface, 2.Giving me twenty breaths per vent at 132 feet. I have no means of monitoring the pO2 YET! The second I have my scrubber filled properly, I intend to test these beliefs. I will not be alone, and if a Mod1 class for converted ida72d2' s were offered, I would of course be the first in line. Now that my dirty little secret is out, is anybody still willing to talk to me, or have we already reserved a space in the memorials? LOL Whoa! Good on you for asking before you did anything.... Im hoping the drivel Im about to spill out isnt teaching you to suck eggs.... SCR's in concept are meant to be operated with Nitrox (or trimix), never air. Why? Two reasons why air is a poor choice of drive gas; 1. You'll drop the Po2 quickly. 2. You end up with a breathing mix that is MORE narcotic than air alone. If you're deep enough to be able to utilise the low PO2's the (1) generates, you're deep enough that you dont want to be narced. If you've not already discovered it, Ake larsson's site is a good reference. This thread also has some useful calculations, although Im not sure how relevant they are for you, since you dont mention what your addition/venting technique is. I'd suggest reading up very carefully about addition/venting techniques, since there are VERY few SCR units out there that I'd trust to operate without a PO2 monitor. I certainly wouldnt run manual like this.... Good luck, be safe! __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers Last edited by EBT : 8th October 2006 at 14:04.
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10th October 2006, 03:50	#13 (permalink)
robertfondren New Member Current Rebreather/s: Ray Other Rebreather/s: Not Bought Yet Ray Join Date: Mar 2006 Location: u.s.a. Posts: 79	Re: scr bailout from mccr All of you are right. Input appreciated.
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