Deodiaus wrote:
Thermite was used to weld them together 100 years ago.
You can buy it off EBay.
Or make your own.
Aluminum powder and black rust.
Black rust FeO4 is formed when iron rusts underwater.
Brown rust FeO3 is formed when iron rusts in air.
You have to grind it up into very small particles.
You use to be able to buy alum powder in an old fashioned hardware
store.

here you go:
http://cgi.ebay.com/EKHART-5413-POWD...-/390220806689