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Author Topic: Make a gasket for your plastic Big Mouth Bubbler carboy  (Read 4862 times)

Offline Philbrew

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Make a gasket for your plastic Big Mouth Bubbler carboy
« on: February 03, 2015, 04:22:21 pm »
About three months ago I decided that I needed to drink more beer and less whiskey.  After all, beer is more healthful than whiskey.  (The opinions of residents of Kentucky, Tennessee and, uhm, Scotland may differ.)  Problem is I can’t buy the beers I like to drink (mostly German/Czech style pils and lagers) in Hermiston, OR. 

Solution = homebrew.
I bought three 6-1/2 gallon plastic Big Mouth Bubbler (BMB) carboys.
 
They have many attractive features for me:
  Tall and skinny.  Two will fit in a smallish old fridge I have.
  Clear.  I can watch the action.
  Light weight and non-breakable.
  Easy to clean.

They have one problem:
   None of the three that I bought would seal well enough for an airlock to bubble.

After several failed attempts with silicone sealer and o-rings and such, I found this rubber gasket material at my local Ace Hardware (of all places):
   “Watts” white food grade buna-n gasket material
   1/16” thick x 1’ wide
   General purpose FDA approved food handling material
   Excellent abrasion and gas resistance
   Ace stock # 4119962

The stuff is spendy, about $14.50 a lineal foot.  But Ace will sell it by the inch and a 6 inch x 1 ft. piece will make two gaskets.


So, cut your piece into two 6” x 6” squares and center the white lid of your BMB on one of them, flat side down.


Trace the inner edge of the bung hole (or holes) with a pen or fine point Sharpie.


Carefully cut out the hole around the outer edge.  Place the gasket material on TOP of the lid and push the gasket down around the hole.  This is not for sealing, it just holds the gasket in place.


Flip the lid over and trace generously around the outside of the lid.  Carefully cut out the gasket.  It needs to extend about 1/16” beyond the edge of the lid all the way around (1/8” larger in diameter than the lid).  You can cut it out while still on the lid when it is flipped over by supporting the gasket with your BMB blue bezel ring.


Now, you’re going to install the lid UPSIDE DOWN on your BMB.  Put the lid and gasket in your blue bezel ring and tuck the gasket down in as far as you can.

Sanitize the whole shebang with Starsan and you’re ready to go. 
Well, almost ready.  You may want to tighten the bezel ring beyond what you can do by hand grip on the fairly smooth bezel ring.  I’ve used three number 32 stainless steel, worm drive hose clamps (autoparts or hardware store) to create one large hose clamp.  When all three are carefully tightened equally, they form three equally spaced “ears” for added leverage. 


For even more leverage you can kluge together a makeshift spanner wrench out of a stick and a couple of ¼” bolts with nuts.  This stick is ½” x 1 ½” about 16 inches long


The spanner bolts bear on the backside of the trailing worm drive “ear” and the front of the leading worm drive.


BMB with a 5-1/2 gallon batch of California Common bubbling happily away.  Note the white plastic lid is installed upside down.

Cheers

Edit:  I forgot to mention that you need to make sure that the very top of the BMB has a good sealing surface.  It's only about 1/16" wide.  Lightly sand the top edge of the carboy with fine (220-320 grit) sandpaper to smooth out any irregularities.  Pay particular attention to the parting line areas.  CO2 is very skinny stuff.
« Last Edit: February 04, 2015, 12:00:57 pm by Philbrew »
Many of us would be on a strict liquid diet if it weren't for pretzels.

Offline JT

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Re: Make a gasket for your plastic Big Mouth Bubbler carboy
« Reply #1 on: February 03, 2015, 06:01:18 pm »
Nice job, thanks for sharing!

Offline Philbrew

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Re: Make a gasket for your plastic Big Mouth Bubbler carboy
« Reply #2 on: February 04, 2015, 12:02:50 pm »
I forgot to mention that you need to make sure that the very top of the BMB has a good sealing surface.  It's only about 1/16" wide.  Lightly sand the top edge of the carboy with fine (220-320 grit) sandpaper to smooth out any irregularities.  Pay particular attention to the parting line areas.  CO2 is very skinny stuff.
Many of us would be on a strict liquid diet if it weren't for pretzels.