I'd experimented with melting and stretching clear plastic rods to make my icicles but had little success with this method. I've seen others can achieve great results but personally I found it too fussy and very hard to control. So I tried my hand at another technique.
I cut lots of fine triangular slithers from on old blister pack with a pair of scissors and attached them to a plastic rod for ease of handling. I then used water effects to bulk them up and round them out. The trick here is to work with the icicles upside down so the the water effects pools at the base - where you want the thickest part to be. Just as with the slime and drips technique it takes a fair few coats to build up sufficiently but I'm very pleased with the result. I can trim them to the desired length and fix to the base as and when I need them.