I am trying to repait a 3/4" copper pipe that runs vertically by cutting it and then re-soldering with the help of a joint. Any suggestions?
First you will want to be sure all surfaces are clean, if they are not clean them and scuff them up with a piece of Emory cloth (fine or medium grit) Next coat all of the surfaces to be soldered with a paste called soldering flux this will help the solder stick better. Next assemble the parts to be soldered and unwind about two or three inches of solder then starting with the top joint heat ONLY the outside surface of the coupler or whatever you are using to join the pipe together. As the part gets hot drag the unwound solder across the top of the joint and as soon as the joint gets hot enough the solder will melt fast and easy. Remove the heat source and drag the solder around the entire joint once or twice. The joint will suck the solder in and marry the pieces together. Go to the bottom joint and repeat the process. When you are finished allow the joint to cool for a minute. The slowly apply water and check for leaks. If there are no leaks you have just successfully sweat soldered a joint. If there are any leaks make sure all water is removed from area and re-apply heat and additional solder. Good luck
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How To Solder Copper Pipe
There is no difference in vertical or horizontal soldering. If you prepare the pipe and coupler right, and apply the heat and solder right, it will work. Period. I'm assuming you have a leak, so you are cutting out a section of pipe and putting a short piece in. If you can spread the pipe enough to use a regular coupler, great...if not, get a repair coupler, which doesn't have a ridge in the middle. You prep the pipe and coupler, slide it on one pipe, align the pipes and slide it over the joint. The whole assembly has to be 100% dry. It's virtually impossible to get a good job with any water present. Prep by cleaning the pipe and inside the coupler with a wire brush or emery cloth. Regular sandpaper isn't so good, cuz sand particles can get in the joint. If you use it, wipe the surfaces with a clean cloth before you put the flux on. I like Oatey #5 flux. Put a good coating on the outside of the pipe and the inside of the coupler, and assemble. Apply the heat to the center of the coupler on one side...depending on how hot your torch is, give it a few seconds to heat up good...then apply the solder to the opposite side. If it doesn't melt it, take the solder away and heat it more...you don't want the flame to be melting the solder, you want the joint to be hot enough to melt it. Once it starts to flow, take the heat away and feed the solder in. Rule of thumb: a 3/4 inch joint will take 3/4 of solder, a 1/2 joint will take 1/2, etc. If it doesn't draw the solder in, you may need to take it apart and reprep. A well prepped joint will suck the solder right in, no matter what the position is.
You will need a copper slieve that fits over both ends of the cut pipe. I assume you're soldering with propane tourch? Be advised that solder flows towards the hotter place, so keep the flame where you want the solder to go, but don't hold it there for too long because if it's too hot the solder won't stick. Because you have a vertical section, it is particularly important not to overheat the solder joint, or else the solde will run down. If it starts to run down remove the flame, let it cool, put the flame back on when you see that solder is turning frosty, add solder where needed, repeat this in small steps. You might want to practice on a scrap piece of pipe before you do the real thing because if you mess up it is hard to fix.
