BOULDER, Colo. (AP) ¿ Dynamic Materials Corp., which makes explosion-welded clad metal plates, said its fourth-quarter profit slid 81 percent as sales in its metalworking division fell. The company earned $1 million, or 8 cents per share, for the quarter that ended Dec. 31, compared with $5.4 million, or 42 cents per share, a year earlier. Analysts surveyed by Thomson Reuters expected 13 cents per share. Sales for the quarter fell to $42.6 million from $58.6 million a year ago. The explosive metalworking division saw a 33 percent drop in sales to $31.7 million, while sales in oil field products and the AMK Welding division were steady. For the year, Dynamic Materials earned $8.5 million, or 66 cents per share, compared with $24.1 million, or $1.87 per share, the previous year. Sales fell to $164.9 million from $232.6 million. The company expects 2010 sales to be in a range from the same to 5 percent lower, Chief Financial Officer Rick Santa said in a statement. The company said it has entered new markets in the oil and gas industry and in rail car manufacturing, which could expand demand for its products. Shares rose 23 cents, or 1.2 percent, to close at $19.06. They lost $1.56 in aftermarket trading.