NEW YORK (AP) ¿ Shares of Dynamic Materials Corp. dropped sharply on Friday after the maker of explosion-welded clad metal plates turned in a fourth-quarter profit well below what analysts had been expecting. In afternoon trading its shares fell $2.99, or 15.7 percent, to $16.07. Thursday evening the company said its fourth-quarter profit fell 81 percent as sales in its metalworking division fell. It earned $1 million, or 8 cents per share. Analysts had been expecting 13 cents per share. Jefferies & Co. analyst Yvonne M. Varano left her "hold" rating in place Friday. She wrote that she remains concerned that lower spending in key markets and an inability for customers to get financing could hurt demand. The Boulder, Colo.-based company saw its explosive metalworking backlog fall to $50 million, from $63 million just three months earlier and $97 million at the end of 2008. "A reversal in this downward trend is going to be key to seeing stronger earnings momentum," Varano wrote.