The first thing Arthur Weaver tells you is that he does not even drink beer. But there was this guy who would come asking for empty beer cans at the rest stop near Weaver's gas station in Pine Grove, Pa., and Weaver couldn't really understand why.

Weaver, one of th beer can dealers who came to Greenbelt yesterday for a "Can-A-Rama" at the National Guard Grove, Pa., and Weaver couldn't really understand why.

The 65-year-old gas station owner is one of the more than 10,000 can collecting addicts across the nation. Their ranks include grammar school boys who scrounge for old cans in parks and on beaches as well as business people and professionals whose hobby it is to trav el from state to state seeking out the rarest of beer cans.

The variety of illustrators on the cans that are sold at a collector's convention are nothing like the cans generally seen on most liquor store shelves.

There are scenic cans, like the ones showing a barn in a snow-covered country setting; silly cans, like the "Olde Frothingslosh" models picturing an overweight woman lying on bearskin rug and others like the "Penny At Noon" series which features a blond woman in a scanty bikini.

While many of the more recent cans sold for 50 cents, there were those, like the Playmate model, which pictures a woman's eyes and lips. That one sold for $80 because there is only a limited number of Playmate cans. Playboy magazine supposedly forced a halt to their production, alleging that the beer distributors making them had copied the idea from the magazine, according to Weaver.

Weaver recalled that the first beer can he bought cost him $1.25. He resold it for the same amount to a can-collecting friend who would pass by his gas station every now tand then. But a short time later, Weaver discovered the same cans at a flea market selling for only 25 cents each.

He bought about a dozen and resold them all for $1.25 each. It was at that point, he recalled, that he realized can collecting could be both profitable and fun.

One of Weaver's big deals of the day was with a red-haired little boy who wanted badly to trade a three-ping Courage Jackpot Bitter can his father had brought from England for a Canadian Ace brand cone-topped bottle which is not made anymore.

When Weaver turned down the trade, the boy implored, "Aw, come on . . . I need it for my collection."

Weaver still refused.

He was asking $15. Finally the youngster carried over a Gold Buffalo can and offered that one along with the can from England. Weaver accepted, although the Gold Buffalo can is worth only about $5 and the value of the English can is unknown.

At times, it seemed as though the can show could double as a Boy Scout convention wit hundreds of little boys just like Weaver's young customer driving the hardest bargains.

The adult collectors, according to Dick Baylog of Cleveland, Ohio, "are hung up on a craze." Like, he noted, himself. He was a corporate lawyer who now spends most of his time traveling to beer can shows.

"I'm not making as much money but I sure am having fun," he said.