Old 10-08-2018, 01:04 PM
Senior Member
Join Date: Oct 2009
Posts: 402

The trick for soldering marine wire is using an 80 watt soldering iron. Do not use a gun with a trigger. Use tinned marine wire, and tinned terminals. Put the chisel tip up against the terminal, right where the wire starts to stick out of the crimped area. Wait a few seconds, then apply some solder to the iron itself at the terminal. The solder will melt and quickly flow onto the terminal. As soon as this happens, apply the solder direct to the terminal.

Do not let the solder flow up the wire past the terminal, at least no more than necessary. This will leave a hard spot in the wire, which can break with vibration. If everything is clean, this should work well. Keep a fan running over the general work area if you are doing a lot of terminals, no need to breathe the fumes. I often use lead free solder, but the higher melting temperature makes it more difficult to solder.

For crimpers I use Thomas and Betts, but others work as well: The model I like is the WT111M, you can find them for $35 or so. Also uninsulated terminals, with separate heat shrink, are low cost. More time is required due to the soldering, but 20 years later there should be no problems at all.
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