I'm not familiar with manganese bronze, but I use a fair amount of silicon bronze and love it. You can forge it, weld it, machine it, do almost anything with it.

Using a TIG welder, you can create invisible seams, and it doesn't outgas fumes like brass and some other bronzes. I forges either hot or cold (very easily at a low red heat), and it has a very pleasing brownish hue that really glows with handling. Tough stuff, too. High tensile strength, good section modulus, etc.

The only drawback is the price. Sheet is running around $15/lb, some bar stock the same, some a bit lower. Wonderful stuff, even if spendy!

Manganese bronze propellers have been in common use since the invention of the screw propeller in the 1800s. It may have more to do with the guy coming into a cache of old propellors than choosing the material. They used to come up on auction once in a while and I saw people get the them for pennies a pound. (quite the investment, eh?)

Extolling the virtues of whatever you happen to have makes a good sales pitch.

G.

Gene Olson
Sculptor
Elk River, MN

Would most likely have been selected for it's exellent welding properties. Must be worked hot in a very narrow temp range (1150-1450F) Therefore, silicon bronze, wich also welds easily, and can be cold formed, and is readily available is a better bet.