How to solder copper pipe

You can learn how to solder copper pipe successfully. This article about soldering copper pipe will show you why you may have failed before, and how to succeed next time. We already talked about using the right tools for soldering copper pipe. Once you have everything you need for the project, you're ready to solder!

The Right Flame

The first soldering tip is about using the proper flame for the job. The flame that's right for sweating copper pipe joints is a "rosebud" flame. A cone-shaped flame puts a lot of heat at the one spot it reaches. The rosebud flame wraps the pipe in the flame, bringing the entire joint to the right temperature at the same time.

You're not trying to apply solder to the point where the pipe enters the fitting, but to let the solder run into the joint by capillary action. To do this you want an even temperature over the entire joint. Your rosebud flame will free you to apply the solder at the right moment instead of forcing you to keep that flame moving which plays havoc with your timing.

Copper Soldering Technique

How to solder copper pipe in 3 steps-

  1. Take your time and start with a small flame, just large enough to go most of the way around the pipe.
  2. As the pipe heats up, touch the end of the solder to the joint at ninety degrees from the source of the flame. That keeps the solder from melting off in the flame.
  3. Touch it there every second or so till it runs into the joint.

If you have done this right the solder will go around the joint and meet at the other side mostly by itself. For larger pipe sizes you may need to move the tip of the solder along the joint face. You may be able to withdraw the flame and feed solder into the still-hot joint. It is always better to under-heat than to over-heat when soldering.

As soon as you have ringed the joint with solder, move to the next side of the fitting. Subsequent sides should go faster having already received heat from the initial work. Don't wipe the joint or jiggle it in any way till it sets. You will see if you watch that the solder goes from very silvery to just bright. As soon as this dulling occurs the solder has set.

If the fitting glows, turns blue or “rainbows”, you have used too much heat. let it cool, clean it up inside and out and try again.

More Tips About How to Solder Copper Pipe

  • If in doubt of your skills, practice soldering on some extra copper pipe and fittings. Once you turn off the water and start your project, you're without water until you finish.
  • I don't keep anything on my truck to protect surfaces near to where I solder. The reason for this is that I don't let my flame flare out past the pipe I am heating. I don't say this to discourage you from using a shield, but to help you envision what an appropriate flame size looks like.
  • When I am waiting for the right working temperature to develop I keep touching the solder to the copper pipe joint, I don't lift it back off but rather I draw it off with a pulling motion. Just before the solder runs it begins to leave a mark on the copper like a pencil would. Seeing this helps my timing.
  • The solder you use becomes part of the joint. So does anything stuck to the solder. So be sure to feed clean solder into your joints. If your solder gets fouled in the tool box, clean it the same way you clean the ends of the copper pipe, with abrasion.

I hope these soldering tips have shown you how to solder copper pipe. Soldering those pipe joints isn't really hard once you get the hang of it. Good luck with your project!