The Permatex high temp sealant is good stuff to use. I've not had a single steam leak at any joint where I've used it. I learned about it from David Bailey while at Diamondhead, who said to put it on the male threads only. I use a tooth pick to place the paste on the threads. That makes it easy and you don't waste any paste. I suppose the moral of this story is that you can learn a lot of neat little tricks at steamups.