Wikipedia's page on adiabatic flame temperature is very useful.
Unfortunately the only place I have to use this torch is at home, where acetylene is really not a good idea.
These are much safer than acetylene. However, most people online say that these don't generate the higher temperatures that brazing really needs [2]. It does work in some situations, but there are a lot of limitations (ctrl-F here for "smaller components").
Oxy + MAPP can reach around 2925°C / 5300°F.
Although propane can't attain the same temperatures that MAPP gas can, it's close, and I believe it's easier to access and cheaper (TODO: confirm this). And it's not hard to make a simple fire brick forge that can be disassembled when not in use.
Simple propane forges can sustain temperatures of 980-1204°C / 1,800-2,200°F for long periods of time.
This definitely seems more friendly to the home hobbyist.
In 2023, it seemed like this same handheld design, around $200, was sold under many different brands.
These can heat materials at an even temperature for a long time.
Downsides — they're pricey, they're sometimes only big enough to heat-treat knives, and they often need a 240 volt hookup.
They tend to max out around 1200°C / 2200°F.
See my separate page about this.
Yes, this is absolutely crazy. But still, it's possible.
If you had an expensive capacitor bank, you might be able to really crank up the heat.
See my separte page about this.
The upside — powdered aluminum + iron oxide can reach a temperature of 2862°C / 5183°F. Having that much heat available in a relatively safe-to-store format is really nice.
The downside — While it is sometimes used for welding, it's a pretty uncontrollable reaction, in terms of hitting a specific temperature and holding it there. It's also usually described as a "violent" reaction, because it tends to spit molten blobs of metal in the surrounding area.