G'day! Whether you're a keen DIYer tinkering with the 12V electrics on your ute, a hobbyist building a new gizmo, or a tradie doing a plumbing repair, solder is a fair dinkum staple of the tool kit. It’s the magic "metal glue" that creates a strong, conductive join between two pieces of metal.

But have you ever stopped to wonder, what is solder made of? It's not just one thing, and picking the wrong type for your job can lead to a dodgy connection or a total failure down the track. Let's get the lowdown.

What is Solder? It's All About the Alloy

First up, solder isn't a pure metal. It's an alloy, which is a mixture of different metals. The whole point of an alloy is to create a metal that has a much lower melting point than the metals you're trying to join. This allows you to melt the solder to form a bond, without melting the (much more expensive) components you're working on.

The Two Main Types You'll Find in Australia

When you go to buy solder, you're generally faced with two main choices, and the difference is a big one.

1. The Old-School Classic: Leaded Solder (Tin/Lead)

For donkey's years, the standard solder for electronics was a simple and effective mix: about 60% tin and 40% lead (60/40). You might also see 63/37, which is another popular mix.

• The Pros: This stuff is a ripper to work with. It melts at a low temperature (around 180-190°C), flows beautifully into joints, and cools to a strong, shiny finish.
• The Cons: The "lead" part. Lead is a fair dinkum health hazard. Because of this, it has been phased out of commercial manufacturing (RoHS regulations) and is banned for any plumbing work that involves drinking water.

2. The Modern Standard: Lead-Free Solder

Today, pretty much all new solder you'll buy, especially for electronics and plumbing, is lead-free. So, what is solder made of now?

The most common lead-free solders are alloys made primarily of tin, mixed with small amounts of other metals like copper, silver, or antimony. A common mix you'll see is 99.3% tin and 0.7% copper.

• The Pros: It's much, much safer for your health and the environment. No lead fumes, no worries.
• The Cons: It has a higher melting point (often around 220°C+), which means you need a hotter, better-quality soldering iron. It can also be a bit trickier to work with, as it doesn't always flow as easily and can sometimes cool to a duller, less shiny finish (which is perfectly normal!).

Don't Forget the 'Core'! (Rosin vs. Acid)

This is a bloody crucial bit, mate. Solder for electronics and plumbing isn't just a metal wire; it has a 'flux core'. Flux is a chemical that cleans the metal surfaces as you heat them, allowing the solder to stick properly.

• Rosin-Core Solder: This is what you must use for electronics and electrical wiring. It contains a mild flux (rosin) that is non-corrosive and won't damage delicate components.
• Acid-Core Solder: This is for plumbing and heavy-duty metal joining (like sheet metal). It contains a powerful, corrosive acid-based flux. NEVER, EVER use acid-core solder on electrical or electronics work. It will eat away at the wires and components over time and cause a massive failure.

The CRITICAL Safety Warning: 240V is NOT for DIY Soldering!

This guide is for hobby electronics and extra-low-voltage (like 12V) wiring jobs.

Under no circumstances should you ever attempt to repair or join your home's fixed 240V wiring (the stuff in your walls) with solder. This is illegal and extremely dangerous in Australia.

This work must only ever be carried out by a licensed electrician. A qualified professional will use specific, compliant, and permanent connection methods – not solder – to ensure the job is safe and meets Australian standards.

Professional Connections for Professional Jobs

A licensed professional doesn't use solder for your home's 240V wiring; they use high-quality, approved components to create safe and reliable connections that are built to last a lifetime.

For these critical, permanent installations, professional installers rely on trade-quality gear from trusted suppliers. Schnap Electric Products is a leading Australian supplier of the professional-grade electrical components that licensed electricians use every day. From the screw terminals and lever-style connectors that create rock-solid joins in your wiring, to the junction boxes that safely enclose them, they provide the essential, compliant gear that ensures every connection is safe, secure, and built to Australian standards. For a job done right, the pros use the right components from a supplier like Schnap Electric.