soldering 1/0

Best way to go about this? I am trying to solder the lugs on my 1/0 feed line from my battery.   I have a 25 watt soldering iron and a small butane torch that I cannot use the soldering tips on :( I tried with the torch tonight on some 4ga by heating up the lug. However, I could not get the wire hot enough to absorb the solder without melting the insulation.

If the wire gets hot enough, the insulation is going to melt, no matter what method you use. With a 25 watt iron and a small torch, the torch is your only option. Even if you had a weller 90 watt pencil type iron, it would take a while to solder and the insulation will still melt a little. If you have someone that can help you with the soldering, have them hold the wire back about a foot or so and roll the wire in order for the connector to rotate to allow you to heat the entire connector. While doing this have the iron at a 45 degree angle from the cable so it hits the cable and goes away from the insulation. Get the entire connector hot before attempting to solder it. I use a torch and then use Heat Shrink Tubing to cover the imperfection of the insulation.

Well the nice welding wire had much better insulation that the 4ga I was practicing with and I got them lugs soldered. Just cut the insulation back more, heated it up with the torch and applied the solder.   Then I finished it up with some big shrink tubing. Seemed to work pretty well.

heat shrink is my hero..... especially the self adhesive stuff.

We always use butane torches like this one. Place the tip of the blue flame on the lug and keep it there unit the solder melts. The solder will then allow the heat to transfer from the lug to the wire and will allow you to solder them together. Heating the lug should reduce the amount of insulation that will melt.