Problem SOLDERING copper pipe for water softner unit. Please advise.?

I am sweating in a splice to a 3/4 copper watter line. One side of the splice sweated well, the other side will not take solder at all, it just beads up and rolls off the pipe. The two ends of the pipe and the splice had been cleaned and fluxed.Problem SOLDERING copper pipe for water softner unit. Please advise.?
Are you sure it's really copper, on the other side ? Have you tried sanding it down, to the point that it's real shiny ? Right, you've already done that.Is there any Pipe left over, from the other side, that won't take the Solder ? If so, is there any way that you can test it, and get it much hotter than you would, the pipes that you're trying to connect, just to see if it can be forced to accept the Solder ? If it won't, then you've probably been stuck with some low quality Pipe.I hope I'm wrong, because Copper is approaching $4 per pound .Problem SOLDERING copper pipe for water softner unit. Please advise.?
Assuming that you're not overheating the pipe, you still have some type of contamination on the pipe that won't accept solder. Try cleaning it with some emery cloth (or sandpaper) and then some acetone or MEK to be certain that it's throughly clean.
Is there water in the pipe? Is your gas low on torch? Re sand and flux pipe if you can. Heat the pipe first on all sides then move to the coupling. It works by capillary action and will suck into the joint. But if you are mostly one the pipe it will migrate away.
u have to make sure all of the water is out of the pipes before u start, if there is water it will not heat properly. Once the water is all gone then the pipe will heat and the flux will flow like it supposed to.