I am in the process of redoing my rock now and am doing pillars. I happened to have 2 nice long rocks that I am just attaching other smaller ones to but I have heard of the acrylic rod method too. I am using a little epoxy to start the hold and the bonding them with the reef safe cements i went in on with Anthony. It works great. I think he had some extra if you wanna ask him. The issue I am running into now is getting them to stand up. I am lazy and don't want to order acrylic rods, cus I have looked in every store, so I am using plastic hangers. I am trying to make some sort of legs or something with them. I'll try to get a pic up when I am done with it all.