# Soldering Copper

Part of the Plumbing Merit Badge Digital Resource Guide: [Introduction & Overview](https://merit-badge.university/merit-badges/plumbing/guide/index.md)

*6. Hands-On Plumbing Practice*

> **6d.** Solder a copper connection using a gas torch.

This is one of the most recognizable plumbing skills. A good soldered joint depends on preparation even more than on the flame itself. Clean metal, correct flux, even heating, and patience all matter.

Video: [Copper Pipe Soldering-How to Solder for Beginners Video (video)](https://youtu.be/TOtOpixWTXE?si=Jl_jeHOlvComjB_k)

## The basic process

1. **Cut the copper cleanly.**
2. **Debur the pipe.**
3. **Clean the pipe and fitting surfaces** until the metal is bright.
4. **Apply flux** to the cleaned surfaces.
5. **Assemble the joint** fully.
6. **Heat the fitting carefully** with the torch.
7. **Touch solder to the heated joint** so it flows into the connection.

The key idea is that you usually heat the **joint**, not the solder directly. If the metal is hot enough and properly prepared, the solder will flow where it needs to go.

> **Safety First!**
>
> A torch is never a casual tool. Clear the area of anything flammable, protect nearby surfaces, keep water or a fire extinguisher available, and work only under close adult supervision. Copper and fittings stay hot after the flame is removed, so treat every recently heated part like it can burn you.

**Signs of Good Soldering Prep** — Most joint problems start before heating

- [ ] **Pipe end is smooth and deburred**
- [ ] **Metal surfaces are cleaned bright**
- [ ] **Flux is applied only where needed**
- [ ] **The joint is assembled fully before heating**
- [ ] **The workspace is protected from flame and heat**

> **Be Prepared! What if the solder beads up instead of flowing into the joint?**
>
> - **Possible cause**: The copper may not be clean enough.
> - **Possible cause**: The fitting may not be heated evenly.
> - **Possible cause**: The joint may have moved.
> - **Best response**: Stop, let the parts cool safely, and review the prep steps with your supervising adult rather than trying to force a bad joint.

![Safe copper soldering setup with cleaned pipe, flux brush, torch, heat shield, and adult supervision near the work area](https://ik.imagekit.io/doulacoop/tr:w-800/mbu-assets/merit-badges/plumbing/guide/copper-soldering-workstation?v=3c80aa46)

Soldering teaches careful preparation and heat control. The next option shifts back to service work in tight spaces by replacing a faucet.

---

- Previous: [PEX Connections](https://merit-badge.university/merit-badges/plumbing/guide/req6c/index.md)
- Next: [Replacing a Faucet](https://merit-badge.university/merit-badges/plumbing/guide/req6e/index.md)