I have a vertical 3/4" copper pipe I just cut a section out of which froze and cracked. Now I'm replacing it with a new piece of pipe and two standard slip joints- one on either end. My question is how do you sweat solder when the joints are vertical ? I know how to solder and I know about capillary action sucking in the solder even vertically, and that you make the part hottest in the direction you want the solder to flow. But: once you've soldered in one side of the slip joint when soldering the other side won't it heat up the side you just soldered to cause the solder to flow out ? What order should I solder the joints in or does it matter ? Should I first solder on the slip joints onto the piece of replacement pipe at my workbench so I only have two joints left to solder when I put the replacement pipe in place ? Still seems like in doing so I'd be heating other side of the slip joint that I had soldered at my bench. And how long should the spliced-in piece of pipe be or does it matter ? Just a few inches long to replace all the bulged pipe where the crack was ?
Thanks for any tips (or reassurances if it will work just fine)...
Bob
Don't worry about it. There isn't much that is easier than soldering copper. Solder doesn't 'flow out' of a joint. Just heat and poke. You can splice in any length you want, down to leaving 1/8" between couplers.
Use emery cloth and sand the inside of the couplers and outside of the end of the pipe until they are bright. Apply flux liberally and make sure all mating surfaces are covered. If you clean and flux a joint properly, a leak is virtually impossible.
I like to run the torch around the coupling and melt the flux, just to get any glops out of the way before I start to stuff in solder. Heat the front of the fitting and hold the solder on the back (bend the solder in a 'U') at the coupler/pipe joint. When the solder begins to flow, remove the heat and stuff the solder in - you don't want to overheat the joint. When a drip falls out of the joint, it's done. Solder doesn't 'move to the heat' as is the axiom - you heat from the other side because but once the solder side is hot enough to melt, the whole joint will be hot enough to accept the molten solder all the way around.
Once the joint drips, I usually make a quick pass with the solder around the joint to form a fillet, then immediately wipe around the joint with damp rag while the solder is still molten to fling off any excess solder and drips and make a clean looking joint. Once the solder solidifies, wipe the whole joint down vigorously with the rag to remove any remaining flux.
Do the bottom first on a vertical joint. It'll take about 1" of solder per side until it drips out. Also - solder an entire coupling at once, heat n' stuff on one side, then re-heat and stuff on the other. Then wipe. Also, prep, flux, and install the entire run before soldering. Do all of the soldering at once. Since you are only doing two, get it installed, solder and wipe one joint, then do the other. Done.
JayC
