Here's the situation. I'm trying to pour solid wax rod inside a closed off 3/4" copper pipe. After it hardens, I've been hitting the copper pipe with a weed burner. Then I just poop the wax outta the tube. Trouble is, most of the time I find voids inside the wax cylinder. This is obviously being caused by the wax shrinking. I tried preheating the copper pipe with a flame and pouring in the wax. Pretty much same result. We had a similar thread at AA, but hell I can't find it. Any of you got any suggestions??? I tried heat, maybe I should submerge the copper pipe in ice water and fill it with hot wax?? A small void inside is fine, but much more than that is becoming a problem.