How to sweat copper tubing and fittings

Sweating copper tubing is not rocket science, although it does work under some fairly technical principles. Basically, it works on "capillary-action", where the heat applied with a torch or other heating tool 'pulls' the solder material toward it, filling the space between the fitting and the tubing. When it cools, it creates a solid seal.

Instructions

Difficulty: Moderate

Things You’ll Need:

• Copper tubing & fittings
• Non-lead solder
• Soldering flux & flux brush
• Emery cloth
• Fitting brush
• Propane torch
• Heat-resistant gloves
• Safety glasses
• Wet cloth or rag
• Bucket

1. Clean, clean, clean!
   
   Using the fittings brush (or emery cloth), clean inside the fitting to be soldered to the tubing.
   
   Using emery cloth, clean the outside end of the tubing to be soldered (clean same length of the tubing as will fit into the fitting).
2. Prepare:
   
   Using the flux brush, apply a thin coat of flux on cleaned end of tubing and inside cleaned fitting.
   
   Press the fitting onto the tubing until it seats.
3. Solder:
   
   Using the lit propane torch, heat the fitting, concentrating the heat of your flame toward the center of the fitting; i.e., apply the heat to where you want the solder to flow to.
   
   It also helps to move your torch (i.e., the flame) around the fitting so it heats as evenly as possible all around, thereby ensuring a complete seal all around.
   
   As you apply the heat, touch the end of your solder to the tubing (preferrably on the opposite side from where you're applying the heat), just where it comes out of the fitting.
   
   When the fitting is hot enough, you'll see the solder melt and be drawn into the joint.
   
   When you see the solder fill the joint, remove the heat.
   
   Be sure to use enough solder so you see it fill all around the fitting/tubing connection.
4. Finish:
   Using the wet rag (with gloves), carefully wipe the joint.
   
   CAUTION: Because the soldered joint remains hot, applying a wet rag can cause instant steam, which can cause skin burn.
   
   Be sure to wear the gloves for this step!
5. Test:
   That's it!
   
   Once you have finished and the fitting/tubing connection has sufficiently cooled (just moments), you're ready to test the fitting for leaks.
   
   Slowly turn on the supply, and look closely at your newly soldered connection.
   
   If you have carefully followed these instructions, there should be no leaks!

Tips & Warnings

• Read and follow all manufacturers' guidelines for safe and proper use of tools, equipment and products.
• Wear appropriate protective clothing and equipment.
• Use extreme caution while working with open flame torch, to prevent accidental fire.