How to join and solder wires for the most reliable connections

soldering wire how toHow have I missed this? 

While writing an article on the electrics progress of my £35 model railway project I realised that I’d not covered joining wires and wire soldering techniques.

This is a basic but vital skill to master for model railway construction (poor joints won’t conduct electricity correctly leading to poorly running locos) but while I’ve covered general soldering and recommendations on the best soldering iron and solder I realised I’ve never written a post on wires and how to solder them.

My apologies for the lapse.

Here then is a quick video demonstrating the technique I use to join multi-core wire.

Single strand wire joins

If you’re soldering single core wire and want a very strong join watch this video on how to solder to NASA standards.

I’ve not seen this technique before but I’ll be sure to use it next time I’m working with single core wire.

Where to hold the iron on the wire

One extra point, there’s some debate about whether it’s better to hold the soldering iron on the opposite side of the wire as the solder or melt the solder onto the wire with the tip of the iron.

Personally, I hold the iron to the underside of the wire and touch the solder to the top side.

Once the wire is hot enough the solder then flows onto, through and around the wires. In my mind, this ensures the wire is near the same temperature as the solder and so a better bond is formed.

Holding the iron on the same side of as the solder may result in the solder just melting around the wire and not actually passing through it so the joint isn’t as good.

It may take longer but I find holding the iron on the opposite side of the wire produces a better joint.

Finally, a reliable soldering iron and solder with of the correct mix is vital to good soldering and you won’t go wrong with this soldering iron and solder.

> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.
Founder of ModelRailwayEngineer, Andy Leaning

Andy is a lifelong modeler, writer, and founder of He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.

Afflliate disclosure:The links on this page may take you to carefully selected businesses, such as Hornby, Amazon, eBay and Scale Model Scenery, where you can purchase the product under affiliate programmes. This means I receive a small commission on any orders placed although the price you pay does not change. You can read my full affiliate policy here. I also sell my my own ready to use, pre-made and painted buildings and terrain features. browse the range.

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