# No more leaky DIY CO2!



## playthecello (May 14, 2009)

Now that I've discovered these - http://www.sciplus.com/singleItem.cfm/terms/15549 - I'm done with gloppy silicone that eventually separates from the plastic soda bottle lid.

Here's one in action. (Sorry about the quality. My wife took my camera, so I had to use my macbook's isight)










First the good news - there's a hose barb running through the center, they have a screw that squeezes the rubber for a tight fit, and they only cost $2.75 for a pack of 8.

Now the bad news - the barb is 5/16" OD (not 3/16 standard airline diameter), they measure 1" across (ID of a 2 liter soda bottle cap-end is about 13/16") and the company has a $10 minimum order.

Here's how I overcame the "bad" news -

I started by trying to shave down the rubber until it fit, but I couldn't do it evenly enough and it leaked. After killing 2 of the 8 stoppers in my bag, I decided to re-think my technique. I noticed that the neck of a soda bottle gets wider as you go down, so I got out my hack saw and sliced the threaded cap part off.










I didn't cut low enough and the stopper still didn't fit, so I cut off another 1/8" or so.










To make the hose fit, I heated it up until it was soft, then stretched it over the barb. You can dip the end in a pot of boiling water, or if you're a pyromaniac like I am, you can use fire.

Here's the end result, air/CO2 tight, removable, and (I hope, at least) much much longer lasting than silicone.


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## cell (Mar 9, 2009)

Sounds good! It looks like those "Carbonator caps" for making homemade soda drinks (or beer)!


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## El Exorcisto (Aug 10, 2006)

5-minute epoxy works well too, as long as you pull the blue "gasket" out of the cap.


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## AquaDean (Oct 29, 2009)

That is a great idea, I'd bet that if you went down a couple beverage isles of the grocery store you could find a plastic or maybe glass bottle that it would fit without modification. I'm thinking maybe a gallon jug or one of the juice jugs.

For those that are lazy and don't mind spending a little on overseas shipping I found these caps on eBay and they work perfect on a two liter bottle. The eBay seller is "bbssales" from Taiwan and he sells them for use on brine shrimp hatchers. I bought several of them and they work great for CO2 and for brine shrimp hatchers.


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## playthecello (May 14, 2009)

I tried a gallon milk jug, and the hole was too big. I also tried a glass half gallon jug we had lying around, and virtually every juice and condiment bottle in the fridge. It does, however, just barely fit into one of those square vegetable oil bottles, and it fits perfectly into Listerine bottle, but ours was the 350ml version, which just isn't big enough for co2 purposes.

I also learned the importance of patience and the danger of overconfidence after slicing off too much bottle twice in a row, trying to make a second bottle. (i've cut it twice, and it's still too short!) Fortunately I made a hole that the plug *just* sealed with the last 2 liter bottle in the house. I don't know how I managed it so easily the first time...

El Exorcisto, I've never been able to get epoxy to stick to plastic. Granted, I've never tried it on soda lids, but I've tried it on other plastic things, and it ultimately separated every time. Same with hot glue and silicone. I added a check valve to my co2 line (after a near crisis was averted) and the added pressure popped the aging silicone (8 months young) off two bottle caps, so I decided a re-think was necessary, which led me to these stopper things.


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## ghengis (Jun 11, 2008)

...or you could drill the hole into your bottle lid about 1mm undersize and force the hose thru for leak free operation. Doesn't cost a cent, and no silicone to deal with...


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## TAB (Feb 7, 2009)

I built a yeast container out of some 4" abs pipe, cap, clean out and some 1/4" acrylic, works great.


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## playthecello (May 14, 2009)

A custom built yeast container? That had never occurred to me, but it's a fantastic idea. I could reduce the large pipe down to a 1" slip connector, use these stoppers and have the perfect seal!

I've tried the undersized-hole trick a few times, and invariably the vinyl in the hose compresses and it starts to leak like crazy after a month or two. 

If there's almost zero back pressure on the system marginal connections will suffice, but if the hose is going deep into the tank, or there's a check valve, or a kink in the hose then leaks start showing up in places you didn't know could leak. (like the joint in my metal T-connector...)


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## tenakoon (Aug 12, 2009)

ghengis said:


> ...or you could drill the hole into your bottle lid about 1mm undersize and force the hose thru for leak free operation. Doesn't cost a cent, and no silicone to deal with...


I totally agree with that the only ajustment is to cut the tube at a 45 degree angle so it is easier to pull it through then use pleirs to fully pull it thru to create a waterproof seal


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## cell (Mar 9, 2009)

AquaDean said:


> For those that are lazy and don't mind spending a little on overseas shipping I found these caps on eBay and they work perfect on a two liter bottle. The eBay seller is "bbssales" from Taiwan and he sells them for use on brine shrimp hatchers. I bought several of them and they work great for CO2 and for brine shrimp hatchers.


How much did you pay for your caps?


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## AquaDean (Oct 29, 2009)

cell said:


> How much did you pay for your caps?


cell,

I paid $3.00 each plus shipping, these really work great for DIY CO2.

I know that its really easy to drill or punch a undersized hole in the cap and they pull the tubing through it. But I like bulletproof and this is cheap and as close to bulletproof as I've found so far.

Do a search on eBay for item number 180449837310 and you'll find them.


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