Any fixes, how about using a flat tap washer instead of the o ring? Or maybe both.
teflon tape on the threads?

Is the o ring damaged? If so I'd replace that. Also take a good look at the sealing surface on the screw and the board. Is there a nick or grit?
If you add another washer that'll add another leak path. Tape may work as a temporary solution but I think they're just made to seal on the faces touching the ring

Problem with teflon is that you want it to be tight enough around the thread without bottoming out...

Need an emergency fix? Grab one from your other boards. Silicon?

Also looks like other thread is here, may have a solution: www.seabreeze.com.au/forums/Windsurfing/General/Vent-plug-leak?page=1

The standard Oring is ?8mm(ID) x ?1.5 cross section.

If you change the cross section to ?2mm, ?2.5mm or ?3mm depending in what will fit in the hole it will mnot only seal on the bottom of the hole but also the side of the hole.

The orings can generaly be bought from bearing suppliers for about $0.05c each so you can buy a stack of each for a couple of dollars and test which one fits best then have spares to last years.

I sanded out rough spots on the recess wall and bottom (wrapped sandpaper around a pencil as recommend) and always make sure O-ring has a coat of silicone grease on it. I used a larger oring that made contact with the sides of the recess wall, but it did not last long kinda started splitting into two (like a bagel cut into two halves), so I went back to the stock size oring that only contacts the bottom.

Where is it leaking? And how do you know? That helps diagnose.

Don't tape the threads, if its tight then the air can't pass even when you open it.

Given you are in a cold environment (?) do u even need it?

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Mark _australia said..

Don't tape the threads, if its tight then the air can't pass even when you open it.

Good point. He'd have to totally remove the screw if he taped the threads after a session.

I used to put tape on the threads on one old board. It's ok as long as you unscrew it far enough so it's obviously loose in the hole.

As an aside, who made the tool to re-cut the seat (Imax was it you?)
I want one as I visually check the vent on all boards I make but to just use a tool to ensure its good angle, flat etc would be nice insurance.

I use surfboard wax over my vent plug.... I have trust issues. I always unscrew after every session and then screw in before the hitting the water and push the wax around to cover the vent.

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Mark _australia said..
As an aside, who made the tool to re-cut the seat (Imax was it you?)
I want one as I visually check the vent on all boards I make but to just use a tool to ensure its good angle, flat etc would be nice insurance.

I always re seat all holes I come across
I use a drill bit , ( 14 mm from memory ) , that I resharpened to give a slight angle and a radius on the ends ..About halfway between a normal drill angle and flat . The trick is grind the lead angle so slightly that it doesn't grab the plastic and just slightly shave off a ****teenth . Twisting the drill bit by hand , never in a drill.
None of mine have ever leaked , but I'm a non unscrewer , apart from the odd occasion , like in a board bag on roof racks in the blistering sun . I believe a lot of leaking is because of unscrewing . Sand gets in and shreds the o ring and the seat . When an o ring gets sad , it pushes sideways and splits and breaks . My advice to unscrewers is to replace the o ring regularly . They get hard and flatten quickly . As said above , it only coasts a couple dollars for a handful . Id also suggest getting the next size up in cross section .
I personally wouldn't use grease on the o ring , it will attract sand .





Creating this kind of action instead of flat . My theory is , it stops the o ring squashing out sideways .

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Imax1 said..

Mark _australia said..
As an aside, who made the tool to re-cut the seat (Imax was it you?)
I want one as I visually check the vent on all boards I make but to just use a tool to ensure its good angle, flat etc would be nice insurance.

I always re seat all holes I come across
I use a drill bit , ( 14 mm from memory ) , that I resharpened to give a slight angle and a radius on the ends ..About halfway between a normal drill angle and flat . The trick is grind the lead angle so slightly that it doesn't grab the plastic and just slightly shave off a ****teenth . Twisting the drill bit by hand , never in a drill.
None of mine have ever leaked , but I'm a non unscrewer , apart from the odd occasion , like in a board bag on roof racks in the blistering sun . I believe a lot of leaking is because of unscrewing . Sand gets in and shreds the o ring and the seat . When an o ring gets sad , it pushes sideways and splits and breaks . My advice to unscrewers is to replace the o ring regularly . They get hard and flatten quickly . As said above , it only coasts a couple dollars for a handful . Id also suggest getting the next size up in cross section .
I personally wouldn't use grease on the o ring , it will attract sand .





Creating this kind of action instead of flat . My theory is , it stops the o ring squashing out sideways .

Yes grease can attract sand, but silicone not so much, I look at oring before screwing in and have not seen sand accumulating.