The molds I am using are aluminum, concave top, and a single wick hole. I purchased these about a year ago and just decided to give it a try to see if I could come up with a decent looking pillar. The pillar looks great, but now I need to find a single wick that will do the job. Someone suggested cotton core, 45 ply braided for this size. The only kind of wicks I have at the moment are the ones I use in containers; zinc, LX, ECO, and CD. I have tried an LX 30, but it doesn't quite reach the sides when it melts. I think I have read in another post, you should have about 1/4 inch to 1/2 inch left at the sides to be able to hug them. Mine melted out to within an inch of the sides. I'll keep testing other kinds of wicks to see if I can come up with something. Maybe trying to burn a single wicked 4 inch pillar is going to be more than I what I want to try. I may just stick with smaller pillars until I get more experienced with this. Thank you for your input. Your help is greatly appreciated!