A few questions about sweating copper.
I am no stranger to sweating copper, but it's been years since I did it an I am somewhat rusty. I have two questions.
1) I'm not clear on, does the pipe have to be completely free of water to properly solder? If there is a drop or two of water but the fitting heats up and solder flows freely, will that make a good joint, or does it lead to a weak or cold solder joint if the pipe is not completely free of water? I had a joint or two where I know there was some water, but I could see the solder melt well and suck into the joint.
2) On one of my joints, not in a joint with some water in the pipe, the joint seemed to not suck the solder into the joint, it seemed to flow and make a bead around the lip of the copper coupler, but I could not see it sucking into the joint, as I can recall. I think it was on a pipe that already had some solder on it that I had unsoldered without cutting. Could it be that there was already enough solder on the pipe that more did not need to suck into the joint, or does that sound more like a cold solder joint?
I should note I very carefully prepared all these joints carefully with a wire brush tool and the emory cloth, and used a light coat of oatey flux on the fittings and the end of the pipe.
I don't remember ever having a sweat joint I did leak on me later. But I was reading about so many little things, don't use too much flux, put the flame exactly where you want the solder to suck into, let the joint cool on it's own, don't cool it with water, and all that stuff made it seem like if you don't do it just right you could have problems later!
Any input on all of the above would be great!
Lee