The 'E' Type Forum

Good morning all,
I am changing the alternator to an ACR type and need to solder on the heavy terminals that connect the cables to the terminal post located just under the heater box. ( battery cables on one side - not changing them alternator cables on the other)


My normal soldering irons won’t give enough heat, I’ve got one of those 100 watt soldering guns but still no use.
Any thoughts on how this can be done. I’m fairly competent with electrics but need to get a good firm joint not dry.

Thanks

Cordless butane soldering iron should work although you might be better with using a small blow torch.


But if you cannot use a naked flame you could try a 300w electric soldering iron:


https://uk.rs-online.com/web/p/products/7719524/

Hi.
Soldering can be difficult with large objects especially with an inadequate iron.
Some of the soldering guns, especially those that heat by working as a transformer and passing a large current have a tip with a very small thermal mass, so the heat they do generate is very quickly transferred to the object to be soldered and then they can’t transfer enough heat to keep up. A small contact area makes matters worse.
Having said that there are ways of helping transfer more heat energy to the objects being soldered.
Start by resting the iron against the outside of the terminal you are trying to solder and gradually feed some solder to the tip of the iron so as to increase the contact area between the iron and lug. This puddle of solder can transfer a lot more heat energy. As the terminal and wire begin to reach temperature feed the solder into the lug where the wire enters.
If will also help if the lug and wire are very clean and shiny. Finally, I have used a small blow torch to solder very successfully or even the cooker hob to heat an object before I start soldering.
Good luck.

Very useful response, thanks chaps

IMO Prior to soldering the terminals should be crimped. A simple soldered connection can come loose with stress, vibration, and heat. You will find connectors of large gauge are either factory crimped, which is very clean, or crimped upon on site fab which is not so clean but effective. Crimp, solder (or not on large gauge cables), and shrink with Heavy battery terminal shrink tube. It will come out nice. There are battery terminal crimpers made for this purpose, you use a hammer with them and they are reasonably priced.

I find that if you use an open flame you need to use a plumber's flux which is quite aggressive to avoid a dry joint. When I wanted to solder the brass rear quarter window upright without ruining the chrome I bought a 300W soldering iron similar to the one in David's picture above off eBay. Around £10, did the job fine, dubious build quality and electrical safety

Also, with an open flame the insulation tends to shrink back more.

Be sure to use a non-acid flux like rosin on electrical connection. A large solder wire with rosin core should work. Acid flux cannot be cleaned out of the joint and will result in corrosion.

Job done Gents ! The good advice here proved useful. I bought a Dremel Versaflame from Screwfix.
Useful bit of kit, enabled me to solder the heavy brass connectors without melting the wire covering. Flame was very controllable.

This forum is so full of those more knowledgeable than I. People are so willing to share knowledge and experience. May it long be so.

Tim