Quick Splices?

I usually use the crimp type with heat seal that spooges out when you heat it up. For inline repairs in unsheltered locations, I like them because they provide mechanical support in addition to weather sealing. Plus they're typically semi transparent which can allow visual inspection.

I have seen and done too many botched solder jobs to recommend them unless you're quite practiced, as the solder can incite stress on the wire at the end of the solder joint if the joint is prone to any mechanical stress.