Hi Christopher,
Key issue with a cap is __surface_area__ and not the internal volume of one
pole.
Think about this for a bit and then think of just how many beer bottles you
could fit into the same area described by your cylinder.
Two examples:
#1) - Your big bucket is 9" in diameter and 10 inches tall.
#2) - You have three beer bottles and they are 3" in diameter and 10 inches
tall.
Circumference = Pi*diameter
Cylinder surface area = circumference*height
#1) - 9*3.141 = 28.269 and 28.269*10 = 282 Sq. In.
#2) - 3*3.141 = 9.423 and 9.423*3 = 28.269 and 28.269*10 = 282 Sq. In.
And with option #2, you can pack at least two more 3" beer bottles in the 9"
circle described by #1.
Allowing for a bit larger container, you can pack nine or more bottles and
yield three times the capacitance as with your single-wall large cylinder.
Use your treasure for something else and start collecting Corona beer
bottles or start saving the $50 or so needed to get an MMC cap set.
Dave