Copper pipe that wont solder.

[syncman]

Hot water heater replacement. The old copper pipe seems thicker and darker than the new, and wont solder for anything. The new pipe and connectors melt the solder and flux, coating the entire joint in seconds. The old pipe will not cover "tin" or solder. No matter how long I heat it with the butane torch, the solder melts but will not stay on the pipe. Just beads and rolls off. Any help? I did clean with wire brush and then coat the pipe with flux.

[cacher_chick]

Butane? Really?

I would first try cleaning the pipe with emery cloth. If it's not shiny, it's not clean, and if it's not clean it won't hold solder.

I think most of us use MAPP gas or Propane. Butane might work for thin-wall copper, but I have never tried it.

[takatsu]

Hi!

I'm not a pro, but use sandpaper or emery cloth and polish around the end, well past where the fitting will be. The copper must be bright and shiny. Old pipes oxidize on the surface and turn dark- they won't take solder even with flux. Also be careful heating the pipe too long with a torch. It will change the pipe and soften the copper. If you've produced a pinkish/orange colored copper, you may want to consider cutting that section out a few inches back. I take it you need to solder a fitting onto an old section. The fitting should be brushed on the inside with a fitting brush- a couple of turns is not enough. A new fitting is shiny most times, but it still needs to be cleaned with many turns from a brush. A picture would help.

[jadnashua]

Truly clean is a requirement! Some of the fluxes are not very DIY'er friendly. The one I prefer is one that has powdered solder in it. You still need to add solder, but it helps to pre-tin the connection.

[syncman]

Sorry, make that Propane. The blue tank? Really scrubbed those joints in and out with the wire brush cleaner thing. Just wont catch on the old pipe. Have used a Shark bite on one, but the other has no play in the pipe, or space to allow for the shark bite.

[hj]

If you did everything properly and the solder will not bond, there is nothing we can do to help you, because we think WE could do it.

[jadnashua]

Depending on what you use, it could itself be contaminated with oil or some similar material, contaminating the pipe or fitting. If the copper is really clean, solder will flow and bond.