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Buddy commando and the mini cylinder

Discussion in 'Dive Equipment' started by Pothole, May 10, 2017.

  1. Pothole

    Pothole Member

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    guys, so I managed to pick up a second hand buddy commando which came with the mini cylinder (surprisingly the bcd has no fading at all compared to others I have seen forsale). Where the cylinder sits there appears to be a section next to it which I guess would have a valve for the mini cylinder to attach to how ever this has a blank over it. So my question is this, from peoples experiences of the BC BCD is it worth having the mini cylinder or ditching it?
     
  2. jb2cool

    jb2cool Moderator
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    Leave it with the blanking cover and ditch the cylinder. If the BCD actually had the fitting for the cylinder I'd even pay the extra few quid to buy a blanking plate for it.
     
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  3. nickb

    nickb Active Member

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    The mini cylinder comes in handy for carrying helium as a bump gas for calibrating your trimix analyser.
     
  4. Dave Whitlow

    Dave Whitlow Well-Known Member

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    I'll take the mini cylinder off your hands and cover the cost of a blanking plate.
     
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  5. Tel

    Tel Super Moderator
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    Ditch it.

    If a Buddy comes in bottle gets stuck on fleabay and for a couple of quid a blanking
    plate put on especially if it's a Pioneer as this get in the way.

    The other term for this is suicide bottle BTW.
     
  6. Wibble

    Wibble Fish don't talk
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    Is the mini cylinder like the crack bottle on the AP SMB?

    Oh, and what's the "minimum pressure" to fill a crack bottle to get a stiff blob?
     
  7. jb2cool

    jb2cool Moderator
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    If you know the volume of both the blob and the cylinder you can work this out. I think these buddy cylinders are something like 0.5L
     
  8. Wibble

    Wibble Fish don't talk
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    They're 200ml. 120 bar is only enough for a floppy blob.
     
  9. jb2cool

    jb2cool Moderator
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    The volume of the DSMB is around 44L according to my very crude calculations. If the crack bottle is 0.2L then this needs to be filled to 220bar for the DSMB to be totally full at the surface.

    This is interesting as the AP Diving website says their cylinders are only 0.1L which even if totally full would leave you with a floppy blob.

    Half full cylinder = half full blob.
     
  10. Wibble

    Wibble Fish don't talk
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    Just measured it. 19cm (flat) by 125cm. Cross-sectional area = πR2 = 3.1x(9.5x9.5) = 280cm2, volume = CSA x L = 280 x 125 = 35 litres

    Min pressure would be 35 / 0.2 = 175 bar.

    Looks like there's a non-return valve in the connector too which should help prevent water getting into the cylinder. However, disconnecting the cylinder and leaving it overnight left it quite deflated.

    Still hate that webbing loop on the bottom. Nasty snag risk.
     
  11. Dave Whitlow

    Dave Whitlow Well-Known Member

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    I have a buddy commando and am unaware of any snag hazard. Please explain what I am missing.
     
  12. Wibble

    Wibble Fish don't talk
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    Ding. Thread drift. Blob not BCD
     
  13. hawk

    hawk Doing It Rong
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    I can categorically confirm that the crack bottle (filled from a 180 bar tin) is sufficient to give a stiff blob.

    I know this because I have done it on a drift dive and a captain insisting on a blob being deployed from the start. This was especially amusing as I watched muppets try and fill a blob from an octo on the deck!
     
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  14. Tel

    Tel Super Moderator
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    Yeah just bigger. Has the same valve etc.
    Well that's how I do it, I use an Octo :)

    Trick is you put the Octo in the pocket close the material around the body of the reg and hold it tight against the hose.
    Press the purge through the material and up she goes tight as a drum :)
     
  15. JohnL

    JohnL Well-Known Member

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    I should think that GCHQ is having a field day monitoring this site.:joyful:
     
  16. Dave Whitlow

    Dave Whitlow Well-Known Member

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    The cylinders supplied with the pre-2007 Buddy jackets (the subject of this thread) are 0.4l and if someone has one to spare I'll take it off their hands.

    The cylinders supplied with the crack bottle SMB are 0.1l, although there was a batch of 0.2l cylinders made some years ago.
    Contrary to the flawed maths on this thread the 0.1L cylinder is quite sufficient to fully inflate a Buddy SMB.
     
  17. hawk

    hawk Doing It Rong
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    Is the right answer :)

    But none of the muppets on the boat seemed to grasp this and one even started trying to blow his up like a balloon :)
     
  18. Vanny

    Vanny Active Member

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    From experience you'll need a cylinder with close to 200 bar to adequately fill your blob. I occasionally top my up from my 7ltr bailout which is just about 200 bar and it works a treat.

    As for inflating on a boat just stick your face in the flaps () and blow. Don't take that many breathes and your well ard.
     
  19. Tel

    Tel Super Moderator
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    Hah love it. Tempted to do that next time with students and then i'll just use the Octo :)
     
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  20. Wibble

    Wibble Fish don't talk
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    Checked. You're right, it's a 100ml bottle. I'm wrong. Oh woe is me... I will just have to go and jump into Stoney this weekend as a penitence.

    How's the maffs flawed? Area = πR2, cylinder volume is area x length
     

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