Sweating Tips?

I'm trying to sweat a 1/2 coupler onto a 1/2 copper pipe. It's just for practice. The coupler and the pipe are both brand new, I cleaned them outside and inside with a wire brush and sandpaper. I put flux on the same areas, put them together, and then tried to sweat them.

The problem I run into is getting the solder to stick to the pipe. Mine seems to just melt into a big blob. I figure I'm close but I'm missing something small. Not enough flux? Temperature too hot? Something else?

TIA

If you heat it too long ( a 1/2" fitting should heat up within a minute) the flux burns away. Make sure the solder is melted by touching it to hot metal. DO NOT let the flame melt the solder.

This is the video I saw on how to do it, of course along with having seen it done a few times:


Go to about 5:25. How is that technique?

I took your advice, and watched a few videos and I think my technique is a little bit better, but I'll keep practicing.

This time I wasn't able to get a bevel like I wanted between the fitting and the pipe itself, but when I pulled the fitting off there was certainly a good amount of solder on the pipe itself. I don't know if it was too much but I'm sure that even without the bevel that pipe wasn't going to leak (if it were an actual supply line rather than just for practice).

I saw one fault with the video. He states you have to get a lot of heat to the pipe and fitting if there is water present. Wrong...you absolutely can not successfully sweat a joint if there is any moisture present. Even if the water is some distance away from the joint, the heat will still create steam and that will prevent the joint from heating. So NO water...zilch, nada, zero. I didn't particularly care for his application of heat to the pipe, but he didn't overdo it, so probably no harm, but the fitting is what you should apply the heat to and rather than going by color change to determine if the joint is hot enough, when I think the joint may be about ready, it touch the end of the solder to it. If the solder doesn't flow, I pull the solder back and apply more heat. You soon get a pretty good sense of how long it will take to get the joint hot enough, but as stated previously, too much heat burns the flux off and without flux, no solder flow. (capillary action)

PLEASE! A toothbrush, and 80 grit sandpaper?


The 'bevel' you mentioned is NOT a mandatory part of a good joint. It would not make a joint good which otherwise did not properly flow!