I bought a wide mouth demijohn on line (4.5 " opening). Those demijohns come with a plastic lid that is not air tight what so ever. I have not been able to find a plug / bug to buy for it. Any suggestions?
Size 38 or 39 tapered cork available through ebay, or google it (Probably $3-4)
Or a size 15 rubber stopper and it's looking like prices range from $25-50 available from link belowhttp://www.hvchemical.com/stopper-size-chart.htm
a fernco or no-hub reducing coupling for 4" ABS pipe is $3-4 at Lowes/Home Depot.
A few inches of 2" plastic pipe and your back to cheap, easily available stoppers
Doesn’t this rubber reducer "AKA, rubber boot" gives a rubber flavor to the beer?