4” Column Build Assistance

[Nole_Brewer]

Hey all,

I am in the process of building a basic 4” column, 24” in height, on a standard 1/2 barrel keg.

I already have a TC Ferrule on the top of the keg and the corresponding Ferrule for the column, my main isssue is how to easily & cheaply close off the top and connect to my condensing arm?

Any help would be appreciated. Parts list would be great.