Hey Mark, I have different sizes of scrap wire laying around and I usually find one that's fairly snug and just ram in down into the styrene tube. I then can heat and make bends that sometimes must be sharp and hold it in place until it cools. Afterwards (sometimes have to grip with some pliers), I yank out the wire leaving me with a good tight bend that didn't collapse because of the wire inside). Cutting those kerfs like you did certainly makes sense though and there might be a time that I will have to try that method!