I agree. MAPP gas works great for small things, and it sure is handy. But it can't generate enough heat for big stuff. So use it for what it's good at, but understand it's limits.
You might want to check out web sites or even your library for info on soldering and brazing. Years ago I found a simple little book on those topics at my public library, and it saved me a whole lot of trouble. Following the instructions in that book, I didn't find brazing to be difficult _IF_ the material is hot enough. But until it gets really, really hot, you'll find the brass (or brazing rod) sticks but won't run into the joint. Practice on some small bits and pieces of scrap first--some stuff that you can heat up easily. Then you will know what it looks like when it is working well. For small stuff, you may want to use flux coated (white) brass brazing rods. Very convenient and helps simplify the learning process.
Another problem is how to hold stuff. You sometimes have to make a wire jig to hold the parts, or actually rivet them together. The amount of heat required sometimes prevents your being able to just hold them with a pair of pliars like you might hold something you hope to soft solder. So you have to think it through. Sometimes it helps to also "tin" both parts before they are joined. (That is, melt some brass onto the surfaces while they are separate, and then put them together and reheat them.)
Like Mark, I use borax. There is art in learning how much to use. The excess globs up in a glass-like mass that resists filing, but it can be chipped off.
Be sure to use good ventilation!