Electron Beam Welding - From American Scientist Online

In a longer article called To Boldly Go (Again), American Scientist has highlighted a newer welding technology worth noting...

From the article:

"...Similar physical principles are behind a second Star Trek-like technology now coming into use, something called the "plasma window," which is the brainchild of Ady Hershcovitch, a physicist at Brookhaven National Laboratory. Hershcovitch conceived of the plasma window to serve in electron-beam welding, a technique used to fashion metal welds that are narrower and deeper than what can be accomplished with conventional tools.

The chief drawback of this technique is that the electrons used for welding must be accelerated in a vacuum (just like, for example, the electrons that light up the front of a television picture tube). Hence the objects being welded together must normally be placed within a sealed chamber from which the air has been extracted. With that constraint, one cannot make welds to, say, the deck of a battleship. Even for small work pieces, pumping down the vacuum chamber each time an object is inserted is time-consuming, making this form of welding rather costly."

Give it a read. Fun stuff in any case.