Soldering/Useful tips

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Many become frustrated with their attempts as soldering. The issues include:

  1. Iron is unsuitable for the task
  2. Iron is not hot enough
  3. Old solder with expired flux
  4. Attempting to solder incompatible materials
  5. Surfaces to be joined are contaminated

A better, hotter iron, with new solder or additional flux applied to the work go a long way to improving the results. Since modellers tend to solder copper and copper alloys, incompatible metals are unlikely.

Preparing a New Soldering Iron

  1. Screw on/in a new tip
  2. Heat the iron
  3. Soak the sponge on the soldering iron holder in water. It should be damp, not dripping.
  4. Remember to clean and dry the sponge when done
  5. If possible, use distilled water with the sponge.

Tinning the Iron

Tinning is the process of applying solder to the tip. This cleans the tip, allowing easy removal of dross, and a small amount of solder improves heat transfer.

  1. Dab solder onto the tip until the solder 'sticks.' Coat the tip evenly. Wipe off any excess on a damp sponge or rag.
  2. From time to time wipe the tip of the iron on the sponge to remove the dross and excess solder that accumulates during the soldering session. Re-tin as necessary.
  3. If you are using an adjustable base, adjust...

Cleaning the Tip

Cleaning the tip can be done in several ways:

  • Damp Sponge
  • Rag
  • Paper Towel
  • Brass shavings/turnings

While the dampened sponge works, it cools the tip. The other methods clean the tip while avoiding cooling it. A quick wipe with a rag or paper towel is very effective.

When Not to Solder

There are wiring applications which should not be soldered. Tinning a wire is a popular method of preparing a wire. This is appropriate if two wires will be soldered together. It makes the wires stiffer and a little more difficult to handle, but it works. Stranded wires should not be tinned if they will be used in the following manner:

  1. Terminal Blocks
  2. Crimped on connections

1. Terminal Blocks

Main article: Electrical_Devices#Terminal_or_Barrier_Strip

When a wire is used with terminal blocks, it is wrapped around the screw in a clockwise manner and the screw is then tightened. When stranded wires are used, the conductors are crushed as the screw is tightened, resulting in a gas tight connection.

The same concept applies to other types of terminal blocks, such as the Euro style or DIN Rail, where the wire is inserted into a cavity and a set screw is used to tighten the connection.

2. Crimped on Connections

Main article: Electrical_Devices#Crimp_On_Terminations

If crimped on terminations will be used, tinning the wire defeats the purpose.

When the barrel of the termination is crimped, the wire is crushed and, in the process, cold welded to the terminal itself, forming a gas tight connection. Tinning the wire eliminates the possibly of forming a gas tight cold weld.

Soldering after crimping is another mistake: If the connection is gas tight, the solder cannot wick into the connection. Soldering has no benefit, and in fact creates a failure point. Solder will creep up the wire, making it brittle, which increases the possibility of the wire breaking in the future.

Renovating an Old Iron

Remove any residue on the tip

  • This can be done while the iron is cold or hot. Most soldering tips are plated with iron, filing will remove the iron plating and ruin the tip. Tips will wear out and become pitted with time anyway. The good news is that tips are almost always replaceable and relatively cheap.
  • A knife can also be used to scrape any dross that has accumulated on the tip.

Make sure the tip is firmly screwed in/on to the iron

  • Loosening, then tightening a tip will break any corrosion that has formed and may improve performance in the process. If the iron is hot, use a pair of pliers and keep your fingers away from the hot bits!

Re-tin the tip.

  • Heat the tip, then dab on fresh solder until the tip is shiny with molten solder.

From time to time while soldering, wipe the tip on the sponge to remove the dross (technical term is 'crud') that accumulates in the process

  • A tip cleaning device made from brass turnings is also useful. Electronics suppliers carry these and other accessories.

Helpful Videos

The following videos may be helpful when soldering:

Further Reading

Hand soldering techniques and various alloys used in the soldering process are discussed. Some guidelines for selecting soldering alloys, characteristics of various solder types, solderable metals, solder selection, the process of producing a good solder joint, and desoldering are discussed. A summary of causes for poor solder connections is given.