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SUPPORT
GRANT LAIDLAW voices
Grant Laidlaw is currently the owner of the Air Conditioning and Refrigeration Academy( ACRA) in Edenvale. He holds a Bachelor of Business Administration and an associate degree in educational administration. He has a National Technical Diploma and completed an apprenticeship with Transnet. He has dual-trades status: refrigeration and electrical. He has been involved with SAIRAC for over two decades and served on the Johannesburg committee as chairman and was also president between 2015 and 2018. Currently he is the SAIRAC national treasurer.
WELCOME TO THE SOLUTIONS PAGE
By Grant Laidlaw
Many people ask for assistance in understanding theoretical and practical aspects of the industry. I will endeavour to enlighten. We are going back to basics as I have questions coming in that indicate that the basic understanding necessary to work in industry is not in place.
Jaco asks: On a technical level, what is the preferred process for using solder to join wires and in some cases circuit boards. We see that soldering stations have the facility to adjust temperature. The question is how do I determine the correct temperatures for soldering? Thanks.
Wire soldering is a process used to join two or more wires or a wire to a connector or terminal. This involves melting solder around the connection point. Soldering wire( solder) is a fusible metal alloy used to create permanent, conductive bonds between electrical components or metal workpieces, typically using a rosin flux core for easier bonding. Common types include 60 / 40 tin-lead and lead-free options, available in various diameters and in lead and lead-free options.
• Lead-based( 60 / 40 or 63 / 37): Melts at lower temperatures, ideal for electronics with excellent flow.
• Lead-free( RoHS compliant): Stronger joints and environmentally safer but requires higher temperatures.
Note: Acid core solder wire should not be used for the joining of copper wires or any electronic work.
EQUIPMENT FOR WIRE SOLDERING
• Soldering iron with stand or soldering station: A basic 40 – 70 watt iron is sufficient for most tasks.
• Rosin flux paste helps improve the soldering process, however rosin-core solder usually contains a sufficient amount of flux.
• Wire cutters / strippers: For preparing the wires.
• Sponge or brass sponge with water: To clean the soldering iron tip.
• Heat gun and heat shrink tubing: To insulate and protect soldering joints.
• Alligator clips: To elevate wires on a surface.
• Safety glasses: To protect your eyes from any splatter.
• Fume extractor or an area that is ventilated.
RACA Journal I July 2026
BASIC SOLDERING PROCESS 1. Prepare the workspace
• Ensure good ventilation.
• Heat up your soldering iron in the stand to the required temperature.
• Clean the tip with a sponge or brass sponge.
2. Strip the wires
• Use wire strippers to remove a small section of insulation from the ends of the wires you plan to solder. Typically, 12mm is what you should aim for. Make sure you do not strip more or less than that, as it will hinder the process.
3. Apply the correct size heat-shrink tubing over one side of the wires to be joined if applicable.
• The heat-shrink tubing should be long enough to fully cover the joint and an additional 2cm on each end.
4. Tin the soldering iron tip
• Apply a small amount of solder to the iron’ s tip. This is called ' tinning ' and helps improve heat transfer.
5. Apply flux( if necessary)
• If your solder doesn’ t have a flux core, apply a small amount of a rosin flux to the stripped ends of the wires. Even with the flux core, adding flux can be beneficial.
6. Prepare the joint
• Spread wire strands and push the wires toward each other, interlocking the strands. Loosely twist the meshed wires. Make sure the connection is mechanically secure.
• Elevate the wires off the work surface and apply flux if needed – flux cleans the joint, reduces oxidation and makes the solder connection stronger.
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