How-To Properly Sweat Copper Pipes & Fittings (7 Easy Steps)

Did you know that sweating a copper pipe actually means soldering it to be leak-free?

Getting the proper tools, materials, and steps in place to properly sweat copper pipes is critical to maintaining a leak-free plumbing system. The benefits of sweating copper pipes yourself include saving a lot of money. In fact, you should be able to do the job for around $50.

This step-by-step guide will be helpful to DIYers and professionals alike.

Closeup professional master plumber hands soldering copper pipes; how to sweat copper pipes

How To Properly Sweat Copper Pipes & Fittings

If you’re new to sweating copper pipes or soldering in general, it can be a good idea to try it out on some practice pipes first. The last thing you want is to damage pipes you want to use and have to start all over during the process. In addition to this how-to guide, there are some great videos online that walk you through how to properly sweat a copper pipe. For example, this video below is a great one to get acclimated to the process.

Step 1: Collect the Necessary Tools and Materials

It’s important to collect all the tools and materials you need before you ever strike up the torch. There’s nothing worse than being in the middle of a project and realizing you don’t have enough material or the tools you have won’t cut it (no pun intended). So to avoid last-minute trips to the hardware store, here’s a standard list of items and soldering tools you’ll need to sweat your copper pipes.

Step 2: Cut the Pipes to Size

The next step should be to cut your pipes to the proper size you need. This will be done with the tube cutter you have or purchased. Copper tubing is a soft metal and is most easily cut using a tube cutter. Make sure to get one that can cut up to 1 inch thick pipes—the most commonly found in residential homes. A hacksaw can handle larger pipes. To cut your copper pipe, follow these steps:

  1. Place the copper pipe into the tube cutter and adjust the blade until it’s taut.

  2. Rotate the cutter around the pipe once, scoring it in a straight line.

  3. Keep slowly rotating the tube cutter until the pipe has been cut all the way through.

  4. Use the reaming tool on the tube cutter to remove the burrs on the end of the pipe. Burrs left behind can cause leaks due to the jagged edge.

cutting copper pipes with pipe cutter to later; how to sweat copper pipes

Step 3: Clean the Pipes and Joints

After you’ve cut the pipe to size, you’ll want to clean and prep the area before soldering.

  1. Use your 120-grit emery cloth to sand the end of the pipe until it shines.

  2. You should clean at least the final 2 inches of the pipe so the fittings have a nice clean surface to adhere to.

  3. You can clean the inside of the pipes with your wire-fitting brush. Gently insert it in the pipe and slowly turn to clean the inside and get it free of any metal shavings or dirt.

Step 4: Prep Your Area for Soldering

Before you begin, make sure you have all the tools you need for soldering and that your work area is clear.

  1. Clear the area of anything flammable.

  2. Lay down your fire-resistant cloths, fire extinguisher, soldering flux, and your propane torch.

  3. Have everything you need nearby, within arms reach, before you begin.

  4. Make sure to put your safety goggles and gloves on first.

Step 5: Apply a Thin Layer of Tinning Flux

Apply thinning flux evenly to the outside of the pipe and the inside of the fittings—any pieces that are to be joined together. Push the joint together until the pipe is completely inserted, then wipe off any excess flux.

Step 6: Heat Up the Joint

Turn on your blow torch and get the blue cone to about 1 1/4 inch long. The longer the cone, the hotter the torch will be, and this length should work perfectly for soldering copper pipe. Heat the joint for a minute and get your positioning right before applying the solder.

man heating the joints of pipes to sweat copper pipes together

Step 7: Flow the Solder

Hold your lead-free solder on the joint until it melts and flows into the joint. Continue all the way around. And keep in mind the solder will cool quickly, so work carefully but quickly.

soldering copper pipes with tin and torsh; how to sweat copper pipes

When the solder looks full around every joint, you’ve done it! You’ve successfully sweated copper pipes to create a leak-free seal. Now, this isn’t something you may have to do often, but knowing how can be a great way to DIY your own pipe replacement when needed.

Professional plumber checking a boiler at home and writing on a clipboard; sweat copper pipes

For Professional Help, Contact 4Front Energy!

If you don’t want to tackle sweating your copper pipes, or are inexperienced—contact 4Front Energy. Our plumbing experts will be there to help sweat your copper pipes and get you back to where you need to be. 4Front Energy offers a variety of plumbing services in the Minnesota area.

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