What to use to crimp 8 AWG wire?

BHOFM

Yes that is my preferred method too, but like all things in life there are other ways, and as long as they work effectively, what does it matter. The only problem is if the system used is prone to failures, we know about it, but continue to do it, then we are asking for problems.

 

All the irons shown will work , the heaviest about 5lbs (used to solder copper roofs) holds the most heat.

The trick is LOTS of heat , very rapidly , as it takes TIME for the heat to transfer.

The idea is to melt the solder in the terminal , but NOT up the wire.

"Solder shall not be the sole means of mechanical connection in any circuit."

Right , the connection must be made mechanically AND electrically.

We crimp, then solder with the roofing iron.

The local phone co has little capsules of goop they use to keep those tiny phone wires from corroding. There un inventoried , so most phone guys will give you a handful. Shmeer it on before the shrink wrap.

A layer of 3x shrink wrap installed over the terminal and for at least an inch beyond is all the strain relief needed and will water proof the wire end.

This has worked for over 35 years , with NO failures yet.

Battery cables are different as the huge load of start amps can melt a poor solder joint and spray solder.

We simply purchase them from a TOP QUALITY supplier that rolls them with a hyd assembly , that is strong enough to cold flow the terminal creating the electrical connection , as well as the mechanical. Not cheap tho.

FF

 

Crimp connectors insist on being done right, but here's an old wireman's trick which gets around the problem if the eyelet is long enough:

Solder the wire with the wire inserted backwards into the eyelet then bend the wire back over the eyelet and lash it securely. This stabilizes the length of wire that the solder has penetrated and prevents it from snapping under stress.

 

>The trick is LOTS of heat , very rapidly , as it takes TIME for the heat to transfer. The idea is to melt the solder in the terminal , but NOT up the wire.

Years ago I worked as a test engineer for Norden (Of the famous WWII bombsight). They were building the bombing systems for the F4 Phantoms. There were lots of soldered connections to both lugs and terminals.

"Solder wicking" (when the solder flows into the wire past the terminal) had to be avoided in these high-vibration military aircraft. The solution was three things (one mentioned earlier here):

1. High temperature soldering iron to quickly heat the joint
2. Exactly the right amount of solder to fill the joint only
3. A heat sink device on the wire itself so that solder would not flow into it.

The person soldering had a guideline on how much (length) of solder for a particular type of joint. You could do a few experiments on joints and find a correct length.

The wire was stripped so that a short section (about 1/16 inch on small wire like #18) was exposed next to the lug. A clip-on copper heatsink was clipped on each connection before it was soldered.

The result was no solder past the lug, and then a heatshrink cover.

Inspectors with magnifiers sampled the connections before the heatsink went on, and a big vibration table was used to torture completed assemblies to check for problems.

I have done something like this, putting lugs on #8 wire on my boat, using smallest needle-nose visegrip pliers on the wire next to the lug, soldering with a 250 watt Weller gun, adding heatshrink.

No failures after 25+ years. Fresh water, though.

So, expose some wire before the lug, use a small heatsink, solder hot and fast with correct length of solder. Should be OK DIY work...