Carboy bung slipping out.

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Jul 30, 2021
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I'm sure this is another newbee question, but here it goes. I'm having a problem with the bungs on my carboys slipping out once set. At first I thought it was just that I hadn't wiped all the sanitation solution off before putting it on. I went back and dried the inside neck of the carboy and the bung. I then pushed it in almost level with the carboy mouth. They still worked their way out in short order. I'm certain I have the correct size. They are the solid rubber ones in 6.5. I've had to resort to taping them in but I'd rather not have to do that if I don't need to. So where am I going wrong here group?
They are white. Oddly enough, I went back to my Amazon order and the pic of what I ordered showed a more beige set.
I am surprised to hear this issue since my experience is that all new solid bungs work well and as they age a few years and harden they don’t seal well. Universal bungs don’t seal well for me but are good for vacuum setups/ degassing.
I would wonder if there was some surface oil contamination on the bung or mouth of the carboy. , , , , interesting
I don't think there is a oil contamination issue. I cleaned both the bung and carboy very well - likely over cleaned them - because I'm new to wine making and didn't want any issues. The bungs seemed soft enough - not that I have any experience with them. All I can say is that they compressed into the mouth easily enough. Or so it seemed to me.
For some reason there is an issue with the white colored bungs sealing. I have always used the beige colored ones with no problem for many years. I tried the white bungs a few months ago and the entire bag of 10 had the same problem of pushing out of the carboy. I also tried them on numerous carboys with the same result. So I ordered the beige bungs this time and have had no problems with them.
I'm going to order some beige ones tomorrow. Seems an easy solution to the problem. Going to have to stick with the tape for now though. Thanks to all for the info.
I may have given the wrong impression. I just racked it out of primary. I still have an airlock on it. It's just the bungs pushing out so I have had to tape the bungs in the carboy's.
Not just you! Carboy Stopper Clamp is a thing on Thingiverse to 3D print your own. I had such an issue with my rubber stoppers just popping themselves out, i went with carboy hoods. I had to find ones that fit my odd carboys, but so much better. I need to find who carries that size now that ECKraus is gone. There's a rubber type with a single hole for airlock, very common for standard carboys that would take a #6.5 stopper, and fits plastic carboy necks. You can also easily find the vinyl caps with two size 'stems' with holes and white caps. Use with airlock or rig up a blowoff tube.
Might be an inelegant solution but I have a piece of thin wood that reaches from the joist in my wine/laundry room to the top of the bung on my carboy which sits on my dryer. I sometimes find that a wet mouth of a carboy and wet bung need persuasion for a day or two. When they have dried it is good. My basement ceiling is somewhat low and yes unfinished in the laundry room.
I have found if you take a piece of paper towel and place down in beside the bung it takes care of this issue. just dry it well then take a small piece of paper towel it should work ,does the trick for me.
It may be the shape of your carboy neck. I've had the exact same problem with 2 of my 12 or so carboys. They are the same no brand 6 gallon size. None of the other carboys do this so I know it's the carboy and not the bung. The sizing is also important. Some glass carboys take a 6.5 stopper and some take a 7. I think the 1 gallon jugs take a 6.5 and the 4L Carlo Rossi jugs take a 6.0. Unlike some here, I like the silicone stoppers more than the gum rubber type, and the silicone hoods are the best.

Anyway, I got tired of the lack of standardization and have basically switched to Stainless kegs in 5 gallon and 15.5 gallon size. And with those, I use exclusively the silicone waterless airlocks.