How can aluminium cables be lengthened for automotive environment?

Question

My company's business is stretching and armouring cars. In the former process we must also lengthen all the wires. We've just come across aluminium cables, which pose a problem — until now we used to cut and solder the cables together with the extension.

The sections we have to deal with are (in mm²):

• 0.5
• 0.75
• 1
• 1.5
• 2.5

I'd like to know what [industrial] options are available to stretch aluminium cables. There is one possibility that is out of question: replacing entire cables with longer ones. We don't have all the connectors since not every single of them is available, some are proprietary and brand-specific. So we're left with actually "stretch" the cables.

So what are the available options?

Answer 1

You can solder aluminium, or at least certain grades. I can solder to cooking grade aluminium foil for instance.

The trick is to buy a specialist multicore solder, with a particularly nasty aggressive flux in it. I find it easiest to 'tin' all the surfaces, then use conventional solder to complete the joint. It needs some practice to get the solder to take, especially getting the temperature right. I don't know whether it is still available, I bought mine 3 decades ago, and still have some left!

One alternative is screw clamps, another is crimp. I'm not sure either would be too robust against possible corrosion of the mating surfaces, unless scrupulously encapsulated after joining. Both would be larger profile than soldering.

Answer 2

This is another solution: Tulsonic

Answer 3

The problem with aluminum wire is that the conductor "cold-flows" when crimped with standard crimp splices.

The most reliable splice that I use is a standard electrical Marrette splice cap. This has a conical spring inside that tightly grips the conductors. These are reliable for decades.

Although I regularly solder aluminum using specialty solder and Flux, it just doesn't seem to be as reliable as a Marrette splice cap.

The downside of Marrette splice caps is that they are physically large.