I just received a ColdHeat Soldering Iron as a gift. https://www.asseenontvnetwork.com/vcc/coldheat/coldheat/115785/ It's a pretty slick little device. The two big things that caught my attention are that it's cordless and they claim that the tip cools off near instantly. Well after working with it a little bit I can say the following:
Don't plan to use it for really fine work. It has a split tip that works more like a welder than a soldering iron.
It works best on smaller gauge wire. Seems like it would be great for splicing wires in the field.
My initial assessment is I don't think it would work well to solder coax or coax connectors. Because of the mass involved with the coax braid and the connectors I think it would be tough for this device to heat them up well. I think with larger wires and connectors we'll see lots of cold solder joints using this device.
Overall, I like it for it's intended use, soldering small gauge wires together in the field. This will come in handy for antenna work.