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All hail the mighty ZOM
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26,851 Posts
Discussion Starter #1 (Edited)
Right. I am pinching twin 12's full of 18/40 cos a chum of mine is buying a twinset and he won't use it. So...

1. Decant 80 bar off the twinset into another identical empty set.
2. Add 20 bar of O2 to the 150 bar left to make 170bar of 27/35
3. Top off with air to 230 bar. I reckon that's 25/26

4. Take the other twinset with 80 bar of 18/40
5. Add 34 bar of O2 to get 114 bar of 43/27
6. Top off with air to 230 bar. I reckon that's 32/14

My brain hurts and I now have a migrane.
 

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Guru
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7,112 Posts
Sounds about right. I know what you're doing but 25/25 is much more useful for everything really. If you get blown out from one thing and have to hold it over for another dive - 25/25 covers anything in the 30ish down to 45m very nicely IMO
 

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Guru
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7,112 Posts
I guessed - they're actually 28/25 and 32/15 - you might be better off cutting some of your own for 25/25 with something like Decoplanner. I'm sure Ian will run through all the options mate :)
 

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All hail the mighty ZOM
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26,851 Posts
Discussion Starter #7
I'm sure he will. It looks like I can get what I want with the O2 I have by only filling to 220 bar. Marvellous.

Decoplanner? Just poke it into the VR3 and Bob's your uncle. I did actually have an Uncle Robert. Miserable bastard he was.

Cock. You're right. 28/25 and 32/15. *sigh* best get the calculator out. Again.
 

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All hail the mighty ZOM
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26,851 Posts
Discussion Starter #8
Right:

135 bar of 18/40
25 bar of O2 to 160 of 30/33 leaving me with 161 bar in the J
Air top to 220 makes a beautiful 28/25

95 bar of 18/40
35 bar of O2 to 130 of 40/28 leaving me with 143 bar in the J
Air top to 240 makes a beautiful 32/15

Anyone fancy a "garage blending course"
 

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A Moderate from 04/01/07-24/12/12
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11,804 Posts
and vPlanner.

Are you sure you are approaching this with the correct mental attitude Woz? Apparently OC Trimix is for the financially profligate. Your scrimping and scrounging gas from left overs is a bit like watching a mate construct a rolly up from the dog ends at the end of a party.

Best thing is to blow off both sets whilst singing the "Chasey sh*gs Herons" song then take it to your LDS (well actually the most expensive dive shop you can find) then demand a "within 0.1 %" tolerance of your favourite gas.

You'll be giving us a bad name with this frugal approach to Trimix diving.... next thing you'll be using 32% and 80% for deco and filling your suit with a whip from your deco bottle.......shakes head .
Mal
 

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www.finingaround.co.uk
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1,826 Posts
It's for my triox course with Ian Dennis. Apparently the IANTD tales are 25/25 and 32/15.

Handy, eh?

Except I've only got 174 bar of O2 in the 47 litre J. Arse. I need 180.
You must have a heat source?

Just warm up the supply cylinder ad you'll get more pressure out of it!


My fingers are getting sore...

Ahh you already are heating it (via the extra warmth geerated by your brain!
 

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All hail the mighty ZOM
Joined
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26,851 Posts
Discussion Starter #16
and vPlanner.

Are you sure you are approaching this with the correct mental attitude Woz? Apparently OC Trimix is for the financially profligate. Your scrimping and scrounging gas from left overs is a bit like watching a mate construct a rolly up from the dog ends at the end of a party.

Best thing is to blow off both sets whilst singing the "Chasey sh*gs Herons" song then take it to your LDS (well actually the most expensive dive shop you can find) then demand a "within 0.1 %" tolerance of your favourite gas.

You'll be giving us a bad name with this frugal approach to Trimix diving.... next thing you'll be using 32% and 80% for deco and filling your suit with a whip from your deco bottle.......shakes head .
Mal
Dont be daft. First thing I'll do is buy a J and cook up my own. There's nowhere round here to get a decent fill.
 

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Registered
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1,342 Posts
Ian will make you use tables :')

So you may aswell leave the VR3 at home.:sad:

It leads to undisciplined technical diving in my book.

Doesn't mean I won't leave home without it.

PS. Your maths looks right. And I'm sure you'll enjoy the course.
 

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Registered
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3,124 Posts
I doubt you'll use 32/15 on the course (there may be mutiny from the safety diver if you do). Speak to Ian, he'll tell you what you need
 

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Registered
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11,575 Posts
Woz, PM me your email and I'll send you my little spreadsheet:





I've ported it to my PDA too, very useful. It's only ideal gas laws, but good enough.
 
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