Vermiculite...coarse or fine?

[DrakeRemoray]

Hi All,

I have 3 kinds of vermiculite available:
#1a - Dime sized coarse
#2 - Coarse
#3 - fine

They all cost about the same. Any ideas on which one best suits my needs for the insulating layer?

Thanks in advance.

Drake

[DavidK]

Coarse, of course!

Although I haven't worked with the other sizes, I think the fine would be too tedious to work with and the Super Coarse would leave many voids--especially when working on the dome insulation.