Timing for this thread couldn't be better.
I usually just unscrew the bung till it pops out a bit, not all the way. On the weekend I was thinking about whether that was actually enough to release the pressure and I took the bung all the way out. The o-ring was about 50% degraded, more of a u-ring.
So what I'm getting from this thread is that o-rings aren't the best because they are subject to friction of the screw, but they will do as long as they are checked and replaced often enough.
So get the thickest you can find, and don't ring its neck when tightening. Just a firm fit to seal the o-ring?
And do I need to take all the way out each time (when dry)? I'm storing in a QLD garage, which can get quite hot.
hello mr evil,
i am allways suss of water leaks, as a plumber i see a few of them, especially on worn o rings,! as a back up i allways keep some blutack with the vent screws (for my old fashioned bung boards
) which i squeeze over the top of the vent once its screwed in place,as an added barrier to water.
checked the o-rings today and on the seat of the vent was corrosion, just a dab of oil should do it and rubber seems ok after all these seasons..no use really to open vent since it's a bit weirdy cool here..and since pressure is the main reason for the vent then it stays in place before i forget to put it back
but i should start doing that by taping the vent with a colored tape once in a while to remind me to close...
Yes, you must have a mantra before you hit the water. Bung: check, harness: check, car keys: check.
Question: Why not a one way valve instead of the bung? 
Question. On it seems a normal !? 40 degree Day in Perth, Do you store your Board, Strap so Up, to let moisture evaporate,(which may have accumulated) or strap side down? And could this method if used, help dry the board out?
ps.after i sail i bring board home wash down.let to dry over night and then remove plug.and store plug in your favourite place. Before i sail i inspect plug hole for sand etc. i then wet plug washer with a bit of spit! which allows O ring to bed better when tightening not to tight.
any thoughts?
OK Snides, I've googled Charles law, and re-read your post.
I guess I assumed a couple of things, which was probably silly of me.
You are perfectly correct if:
You live in a really really cold pocket of WA with a temperature of 20 kelvin. I'm not sure how you breathe at that temperature, because nitrogen isn't a gas anymore.
And I'm dying to see your board that somehow keeps a constant pressure by varying its volume. Maybe it's a windglider?
Sorry for jumping to conclusions before, I really should be a bit more careful.
wow nebs and decrep did you ever wanna be professor of sciences in your past life? concise down to the last letter explanations
A self regulating valve eh... maybe something made out of goretex that lets air through but not water??
Carbonart fit them as standard equipment.
Never bother with a vent screw, or bung ever again. Plus, you can't ever forget to do it up if you never have to undo it.
Price is the issue.. it's cheaper to fit a screw than a goretex vent.
My bags of coffee have one-way valves in them and there are factories in China mass-producing fake dog poo. Surely someone, somewhere can or does produce a stainless one-way valve that manufacturers could use???
hint: www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=one+way+valve+stainless&gws_rd=ssl
I call it a bung from my old boating days. I've learnt to not forget them from then.
Which reminds me:
No. On second thoughts, I just got a mental picture of sailing along and looking down and seeing stribos sphincter winking back at me from where the vent plug should be.
Not a pretty sight.
Better try something else.
also everybody would screw a bung in my anus before sailing
The idea of a one way valve (bike valve etc...) is no good becase I imagine sometimes the air goes out (as it heats) and then it needs to go back in (when it cools overnight)
I do have a board whose internal volume now varies with temperature - a hige bubble in the hull. I tried putting it in the car with vent opening, then doing up plug and putting it in the water - it shrunk down the bulge - but not enough to stop the drum sound as the chop hit it or the feeling I was pushing a lump through the water in front of me. Once the nose was out of the water and I was planing the board sort of worked ! But still made terrible noise. So it now sits in the shed !
Has anybody come up with any visual reminders for tightening the vent screw? I was thinking about something along the lines of disc lock cord you attach onto the brake lever of a motorbike, or something that goes into the mastrack that you can screw it into.
