I have been overwhelmed with requests for photos of the various steam cylinder drains that I have on my locomotives. What I intend to do is to take better photos than I have and post them on the "Notes From Unit Shop" portion of Jim Pitts website southernsteamtrains.com. I will also do a write-up about making them on your desktop lathe. This way the information will be there for anyone to check out. but please have patience as I am in the third to last week of putting the PCLS Summer Steamup on, and I have much yet to do. A good source for isobutane is: Athena International, Inc. 1100 Mark Circle PO Box 398 Gardnerville, NV 89410 (800) 272-8603 www.athenainternational.com They sell it 12 to a case and will ship any where in the continental US. This is the isobutane that you see at most large steamups. I just received 15 cases for the PCLS Summer Steamup. Gaz is a 20% propane and 80% butane gas mixture that gives, on average, a 10% higher vapor pressure per unit of temperature than does neat butane. If you are interested in a complete discussion of liquid gas fuels for use in small scale live steam locomotives please look for an article that I wrote for Steam in the Garden about three years ago entitled "What is the best fuel for gas fired locomotives". Call Ron Brown at SitG for back issues. By the way, butane is not isobutane, and isobutane is not Gaz, and Gaz is not Primus: they are all somewhat and very different fuels with differing characteristics. It's all covered in the article. Best regards, Kevin