|
Hi again Don, When I'm using a propane torch near wood framing like in a joist channel there are two things I do to prevent fires. Sometimes I spray down all flammable surfaces with water from a spray bottle before I light the torch. The other thing is to put something uninflammable on the far side of the flame. In my plumbing tool box I keep several pieces of asbestos house siding with one or more holes at the edges so that I can tack them in place. In a tight situation where a lot of heat is going to be needed I'll often do both. I wouldn't bother to look for asbestos---sheet metal would be adequate to keep the flame off the wood and wouldn't transmit enough heat to be dangerous in the time it takes to make the solder flow. Spray down the wood afterwards, though. To protect valves and previously soldered joints near a new connection in process I will wrap a wet rag around what I don't want overheated. If there is any theoretical basis for this not working, it will have to make an exception for my 25 year success rate doing it. Don, you shouldn't be having a 50% failure rate on soldered joints in the field or anywhere else. I think there's some fundamental element that's bad with your supplies or your technique. I don't mean this in an insulting way. For years I used to consider a sweat plumbing job to be a hit and miss operation. I'd do the plumbing, turn on the water, mark the leaks, turn off the water, and repeat the process until there were no leaks. At some point I came to realize that I had to be doing something wrong. Plumbers typically expect NO leaks on a house sized job. I took the time to reevaluate what I was doing, and to make sure the flux and the solder I used was what an experienced plumber would use. Then I did a lot of practice on mock-ups (you won't want to do this more than once since you have to go to the trouble of pressurizing it.) Now my failure rate is near zero, complex joints and difficult locations included. Just because plumbing is only an occasional job for you doesn't do anything to reduce the frustration you feel when a joint fails. All the best, Stan
|
