[Boatanchors] Your input needed

[telegrapher at att.net]

I planted the base stubs for my tower yesterday in almost 6 yards of 
concrete.  Big hole and the little brown guys that did the work really 
hustled to get it done before the bees returned.

The stubs are 5 ft long and hollow, sturdy material at the least.  My 
question is, what type liquid should i pour down into them to keep the 
moisture (what little we get other than my sprinkler system) from eating 
them out for the inside.  Back in the 40's i have learned that in the 
main spar of some of the airplanes, which was hollow btw, they used fish 
oil.  Stinky stuff when the spar was cut open.  I'd like to pour some 
sort of non-toxic oil in them and then seal the top of the opening with 
paraffin or something meltable and pourable.  Any ideas of what would 
work.  Manufacturer said to pack sand down inside and then seal the 
opening.  BRRRRRRRP!  I wouldn't think sand would be a good option and 
besides i don't want this thing to come tumbling down in 10-15 years due 
to the base stubs rotting out from the inside.

Any ideas here?  Cooking oil, vegetable oil etc. etc.?

Larry
W0OGH