A friend of mine has a weird problem with his downstem. The lip is broken off and he wants to replace it, but he cant get the downstem out, it's stuck at the joint. I need ideas of how to get the downstem out, it doesnt matter if it gets broken. I thought of using a chisel somehow to break the downstem at the joint but I'm really afraid of breaking the joint so I don't really wanna try it. Any ideas would be appreciated. The joint is glass on glass, and there is a perc in the way of going down the tube.