London Metal Exchange (LME) metals eased by Friday's kerb close as profit-taking in thin trading conditions weighed on prices, traders said.
"Things started to come off in the morning kerb - probably people booking a few profits before the weekend. The volumes are thin and the market is behaving a bit erratically," one LME trader said.
However, copper picked up from earlier lows in the last minutes of kerb trading.
"We saw people selling their longs out, but when copper didn't break below $2,800, they bought it back and pushed prices higher," a second trader said.
Other traders cited unsubstantiated reports that a ship carrying 17,000 tonnes of copper had sunk in the Caribbean, as supporting prices.
Traders said the market was unlikely to see significant investor activity before the US presidential elections on November 2.
"When you look at other markets - equities or bonds or precious metals - they haven't moved much. I think fund management groups are wary of putting on positions ahead of the US election," a third trader said.
Copper ended the day at $2,810 a tonne, down $13 from Thursday's kerb close, having diced with support at $2,800.
Traders said that one broker bid the price up in the last seconds to $2,815/17.
Aluminium drifted back $3 to $1,710.
News that alumina shipments from Jamaica could be severely strained for months because of Hurricane Ivan provided some support.
Lead fell $20 to $868. Traders said that despite falling LME inventories rumours of large off-warrant stocks in Asia persisted. Zinc fell $19 to $969. Tin, however, rose by $90 to $9,075.