Aluminum futures roared to a one-year high Wednesday at the hands of a weaker U.S. dollar and ongoing speculation across the entire commodities complex.

Three-month aluminum closed at $2,070 a tonne on the London Metal Exchange, up 5 percent since the start of the week and the highest recorded settlement since November 2008.

But while prices are showing sharp upward momentum, traders of the light metal said technical buying, not underlying demand, is behind the run-up.

"Copper's trading up, zinc's trading up, the whole complex is trading up, and it's...