# Airlock Hole Diameter



## cliffo (26/11/05)

Hey Guys,

I bought a couple of the 25L drums from Bunnings and have to drill a hole to fit the grommet. Can anyone tell me what size the hole should be to fit the grommet snugly?

Cheers,
cliffo


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## Wortgames (26/11/05)

I think you'll be safe with 1/2" (13mm) holes, this seems to be the norm. The grommets do vary though.

FWIW Grain and Grape have some larger 3-piece airlocks, made from a softer translucent plastic and having a tapered tube, so I've been using these pushed into the hole with no grommet. A lot less messing around. You'll need a larger hole (16mm).

Another option is to use a drilled rubber bung in a 1" (26mm) hole.

Grommets suck.

:super:


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## Wortgames (26/11/05)

Oh, and if you are going to use a grommet try to avoid putting it in the lowest point in the middle of the lid - any liquid that collects in the lid (eg condensation, spills etc) will try to seep through the hole and into your brew. I don't think grommets seal very well.


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## vin (26/11/05)

Clifffo

12mm is the correct size for an airtight fit.

Cheers


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## Screwtop (26/11/05)

vin said:


> Clifffo
> 
> 12mm is the correct size for an airtight fit.
> 
> ...




Spot on, 12mm. The lid of one of my 32L plastic fermenters has a 13mm airlock hole. Have to use the two piece airlocks with it as the S bend type will not seal properly (they have a slightly smaller OD tube). Mistakenly drilled 13mm holes in the caps of some of my 2L starter bottle caps (missed by 1mm) and have the same problem with them.


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## Wortgames (26/11/05)

OK, I stand corrected.

Grommets still suck.


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## cliffo (27/11/05)

Thanks guys...off to Bunnings I go....  

cliffo


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## yard glass (27/11/05)

Wortgames said:


> Another option is to use a drilled rubber bung in a 1" (26mm) hole.
> 
> 
> 
> ...



hi wortgames,

this sounds like a good idea, have you used it without any problems ?

cheers
yard


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## muga (27/11/05)

I have seen airlocks with rubber on the bottom, gets rid of the grommet and gives you an airtight seal in a 12mm hole.

Can't remember where I saw them though..


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## Wortgames (27/11/05)

yard glass said:


> Wortgames said:
> 
> 
> > Another option is to use a drilled rubber bung in a 1" (26mm) hole.
> ...



Hi Yard Glass,

I've used it in demijohns plenty of times. I haven't tried it in a plastic lid but I can't see why it wouldn't work.

Here's someone using it in a converted keg fermenter:





:beer: WG


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## yard glass (27/11/05)

WG,
another top idea.  



cheers :beer: 

yard


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## bluc (6/5/15)

Bought two of these barrels today wondering how did you make the hole did you drill it or did you use a wad punch? Don't want to split the lid... Thoughts?


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## Camo6 (6/5/15)

You do realise this thread is ten years old?
As mentioned above, drill it out. Be sure to place a bit of wood under it to prevent cracking.
Or ditch the plastic lid for gladwrap. Just use the lids o ring to hold it in place.


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## bluc (7/5/15)

No I didn't realize it was that old OK thanks will drtill it.


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