Blow Torches

A look in the local hardware store at blow torches finds MAPP gas, 100% propane and a 65% butane / 35% propane type within the range that has other features (eg auto ignition) that I want.

Anyone know which burns with the least heat in the flame? To my understanding MAPP gas is hotter, but what about the other two? I'm thinking that the 65% butane / 35% propane one will be cooler than the straight propane?

I'm looking for the coolest flame not the hottest as that suits my use for it (no soldering, brazing etc).


More...