With two children to care for, David Mohler, a 26-year-old production worker at the giant Eastalco Aluminum Co. here in southern Frederick County, is looking to the future with trepidation.

"I hope they don't lay off, because chances are real good I'd go," he said as he tended a huge casting machine inside the sprawling factory. "I got two kids and it'd be hard, awful hard, to find another job."

Mohler, a seven-year employe, has been through hard times before, but yesterday he was more apprehensive than ever, and with good reason.

Buffeted by foreign competition, high production costs and lingering effects of the 1981 economic downturn, Eastalco is making plans to slash production by 25 percent in October. The move could mean the loss of up to 100 jobs, although company officials say they hope to avoid layoffs.

The company, which now employs 950, was forced to lay off 46 workers in December and January, and Eastalco officials said the worst may be yet to come.

A $36.1 million rate increase being sought by Potomac Edison Power Co., which supplies Eastalco with its electricity, is threatening to make the production of aluminum here even more expensive, raising concerns for the first time about the future of the plant itself.

That was the message delivered by company officials and union representatives yesterday as Maryland Attorney General Stephen H. Sachs toured the plant during a daylong visit to Frederick County.

Sachs, who made the tour as part of his campaign to be elected governor in 1986, met with union officials and 16 plant workers yesterday afternoon before walking through the 400-acre factory with company representatives.

Sachs offered no prescriptions for the company's woes, but he pledged if elected to see that the state addresses the problems of unemployment through vigorous retraining programs and the creation of jobs.

"The job of the state is to see that the jobs are there" -- and not just jobs that pay $135 a week, such as those in the growing fast food industry, he said.

Like other heavy industries, Eastalco for years just rolled with the punches each time the economy turned downward. But this time, a series of factors has left the company saddled with problems that even the national economic recovery cannot cure.

Company officials attributed Eastalco's current ills to a worldwide aluminum glut and a strong American dollar that makes U.S. products uncompetitive on the world market.

Eastalco is Potomac Edison's largest customer, consuming about one-third of the electricity produced by the utility company in Maryland, said Wayne A. Rhoderick, Eastalco vice president and general manager. The company pays $5 million a month for electricity, or 16 to 18 cents per pound of aluminum produced.

In another controversial move, designed to save $2.5 million a year, the company plans to shut down gradually a secondary system of "scrubbers" that remove fluoride and sulfur dioxide from its emissions.