Layout soldeirng tips for wiring you can trust

how to solder wire jointsA step-by-step pictorial guide to soldering strong, reliable, wiring.

There are various ways to connect wires that power a layout. One of the most popular techniques is to use snap lock connectors and good old fashioned terminal blocks are another common approach which I still occasionally use. But the best approach is still soldering, providing the strongest joints.

However, while soldering makes sold joints what really makes the difference to reliable electrical connections is how the wires being connected are presented to each other. You want to maximise the surface area of the wires coming into contact with each other to provide the most contact for the electricity to pass over. Just wrapping wires around each other while easy doesn’t do this.

The recommended approach is to open up the strands of the cable core, weave them together with the opposing cable and wrap the ends around each other and then solder. This gives a reliable, solid, electrical connection between the wires.

Here’s a quick picture walk through guide that explains the technique.

1 Strip the wires

Tool for the easiest wire stripping

First, strip the outer coating cleanly, leaving yourself enough room to work. The easiest and quickest way to do this is with a cable cutting, stripping and crimping tool.


2. Fan and weave the wires together

interweaved strands of a multicore cable for soldering

With the core exposed, separate the strands, fan them out and them weave them together so as many strands come into contact with each other as possible so maximising the contact surface area.

3. Wrap the wires creating a knot

interweaved strands of a multicore cable wrapped around each other for better soldered joints

Take the remains of the wires that poke through and wrap them around each other and then wrap this around the other wire to create a strong tie between the cables. Don’t leave any strands poking out.

4. Solder the join

The soldered joints; strong, reliable, soldered joints.

Finally, solder the cables together. Clean the iron tip, tin it and apply heat to the wires for a few minutes first will allow molten solder flow over and between the strands creating a very strong bond. A variable tip soldering iron and the right solder will really make this much easier, with a small tip used so as not to melt the outer sheath. Don’t forget to clean the tip regularly.

Lastly, cover with heat shrink tubbing and warm gently so the sleeve wraps around the join to protect and isolate it.

I’m now revisiting the wiring of my previous layouts and replacing wiring joints with the above technique and I’m very pleased with the difference it makes.

On a simple OO gauge layout I use to occasionally run my older locos for example I swapped out terminal blocks for the weave and solder joins above and the trains now run much more smoothly.

Sure it’s a slightly harder to do but with a bit of practice it gets easier and my soldering improved in the process. Give it a go and let me know how you get on.

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  1. Very good description, but not clear how one can cover a “T” joint with heat-shrink tubing. Even a straight end-to-end joint needs to have the tube threaded onto one of the wires BEFORE starting the joint, and the tube has to be far enough from the joint to avoid being heated by the soldering process.
    Roger Salen

    • Great point Roger, there are two techniques I use. One, use two pieces of heat shrink, one on the cross bar and one on the leg. The one on the cross bar is slit at one end up to the intersection. Once the soldering is done, I move the cross bar piece up so it covers the join with the slit allowing the leg to protrude. Then I move the piece on the leg up so it meets the first piece. Then with a hot tip I melt the carefully heat shrink where the two pieces join and along the slit so the edges fuse together. Finally, I heat the whole area so the tubing shrinks to fit. It takes a it of practice but can be done. Alternatively, you can cheat and bend the leg so it lies parallel to the other wire (forming more of a Y shape), solder and then run some larger heat shrink over it. Oh, and yes the heat shrink needs placing on the wire before the soldering and keeping a way back so heat travelling up the wire from the soldering doesn’t shrink it in the wrong place but I’ve not had a problem with this if soldered carefully. If I get time I’ll add a quick guide to doing both of these as I can appreciate it’s not obvious. Cheers, Andy

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