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Soldering: The Most Feared Part of Modelling

When the DMG Electech team attends exhibitions, one of the most common questions we hear is, “Do I really need to solder the wires?” For many modellers, the mere mention of the word “solder” brings hesitation, if not outright fear.

But here’s the truth: soldering is not a mysterious or impossible skill. It’s a valuable and often essential technique in today’s electronic world. In this guide (and the soon-to-come video), we’ll tackle the most common soldering task: connecting wires of all sizes.

So, if you’re ready to tread boldly into the world of soldering, let’s begin!

We apologize in advance to those who already have the skills and tools—this guide is for beginners, the curious, and those ready to conquer their soldering fears.

Tools and Materials You’ll Need

  1. Soldering Iron
    • Choose a quality soldering iron. Spending a little more upfront saves you frustration in the long run.
    • Advanced modellers may benefit from an iron with adjustable temperature control, but for most modelling tasks, a 15-25W iron is ideal.
    • (Antex is often regarded as one of the best brands for modellers.)*
  2. Solder
    • To start, use lead-free rosin-core solder. It’s safer and contains flux to ensure cleaner joints.
    • As you progress, you may prefer plain lead-free solder with separate flux, which offers better control and precision.
  3. Wire Stripper
    • Essential for removing insulation from wires. There are many types, from manual cutters to automatic tools.
  4. Helping Hands or Third-Hand Tool
    • These tools hold wires steady while you solder, making the process much easier (click).
  5. Heat Shrink Tubing or Electrical Tape
    • Protects and insulates the joint. Heat shrink tubing is the preferred method for a professional finish.
  6. Sponge or Brass Wire Cleaner
    • Used to clean the soldering iron tip and keep it free of oxidation.
  7. Safety Gear
    • Always wear safety glasses and work in a well-ventilated area to avoid inhaling fumes. A fume extractor is ideal.

Safety Tips

  • Work in a well-ventilated area or use a fume extractor to avoid inhaling solder fumes.
  • Avoid touching the metal parts of the soldering iron—it can reach temperatures of 400°C (750°F).
  • Keep flammable materials away from the work area.
  • Always use a spring stand for the soldering iron to prevent accidental burns or table damage. (Burnt tables rarely go down well with the boss!)

Step-by-Step Guide

1. Prepare the Wires

  • Use a wire stripper to remove 1/4 to 1/2 inch (6-12 mm) of insulation from the ends of the wires.
  • For stranded wires, twist the exposed strands together to prevent fraying.
  • For single-core wires, skip twisting—this is especially important for scenery lighting or other fine work.

2. Prepare the Soldering Iron

  • Plug in the soldering iron and allow it to heat up. A temperature of around 350°C (662°F) works well for most wire soldering tasks.
  • Clean the iron tip using a damp sponge or brass wire cleaner to remove oxidation.

3. Tin the Wires

  • “Tinning” involves applying a thin layer of solder to the wire ends before joining them.
    1. Touch the soldering iron to the exposed wire to heat it.
    2. Feed solder onto the wire—not directly onto the iron—until it forms a shiny coating.

4. Join the Wires

  • Align the two tinned wire ends, either overlapping or twisted together.
  • Hold the soldering iron beneath the joint to heat it evenly.
  • Feed solder onto the joint (not the iron) and allow it to flow naturally into the wires.

5. Inspect the Joint

  • A good solder joint is shiny and smooth. If it’s dull, grainy, or lumpy, it may be a “cold joint,” which lacks strength and proper adhesion.

6. Protect the Joint

  • Slide a piece of heat shrink tubing over the joint and use a heat gun to shrink it into place. Alternatively, wrap the joint securely with electrical tape.

7. Clean the Soldering Iron

  • After soldering, clean the iron tip again with a sponge or brass cleaner. This prevents oxidation and extends the iron’s life.

Common Mistakes to Avoid

  1. Using Too Much Solder
    • Excess solder can create messy joints and even short circuits.
  2. Not Heating the Wire Properly
    • Always heat the wire and let the solder flow into it. Applying solder directly to the iron creates weak bonds.
  3. Rushing the Job
    • Allow the joint to cool naturally without moving the wires. Movement can weaken the bond.

Practice Makes Perfect

  • Practice soldering on scrap wires before tackling important projects.
  • Start with larger wires (e.g., 20-22 AWG) and progress to thinner wires as you build confidence.

With practice, patience, and the right tools, you’ll master soldering in no time. It’s an invaluable skill for model railway electronics, DIY projects, and countless other applications. So, take a deep breath, grab that soldering iron, and start soldering like a pro!  For more information and help on soldering Follow us on Facebook