STAMFORD, Conn. (AP) _ At Vestron Inc.'s headquarters, a five-foot gong sits over the left shoulder of Chairman Austin O. Furst Jr. that he bangs after a major deal is completed or when his company performs well financially.

It rings often.

Since leaving Time Inc., where his last assignment in 1981 was to sell off most of the assets of the company's film division, Furst has molded Vestron from its initial startup into a two-continent operation with 150 employees and sales of $141.6 million through the first nine months of this year.

Vestron is the second largest producer of videocassettes in the country - behind CBS-20th Century Fox, but ahead of the likes of RCA-Columbia Pictures, MGM-United Artists, Warner Communications and Paramount Pictures.

For himself, Furst, 42, has built a fortune of nearly $400 million, $42.6 million of which he took in cash from the company's earlier earnings when Vestron went public in October. He and family members still own more than 70 percent of Vestron's stock, worth about $320 million based on its price of more than $12 a share.

Furst forged his empire through what some have said was a ''parting gift'' from Time. With no cash up front, he bought the assets of the Time-Life video club, a mail-order seller of videocassettes. With the club came the rights to a number of titles in Time-Life's extensive film library.

Furst agreed to pay Time royalties.

Jon R. Peisinger, Vestron's president who previously had marketed Time- Life's video operations, said that in hindsight the rights were ''hardly a gift.''

''Time-Life's investment was $300,000, and they've received about $2 million in royalties from us,'' he said.

Regardless, cassettes whose rights were obtained from Time-Life constituted 78 percent of Vestron's first-year sales of $12 million.

Vestron's first release was ''One for the Road,'' a film featuring the British rock band the Kinks.

Peisinger said that the company, which initially had six employees, persuaded suppliers not to demand payment immediately and was able to get 10 titles out in time for a January 1982 trade show. They included ''Fort Apache: The Bronx'' starring Paul Newman and ''The Cannonball Run'' starring Burt Reynolds.

''We really didn't have a great need for capital,'' Peisinger said. ''We benefitted from very quick success.''

Riding the beginning of what has become a boom in the videocassette market - videocassette recorders now are found in about a quarter of American homes, according to Video Week magazine - Vestron has not had a day of red ink. It earned $2.2 million in its first year, 1982.

Vestron's revenues and earnings have more than doubled each year, from $12 million in 1982 to $45 million in 1983 to $103 million last year.

The company, whose initial business was strictly buying cassette rights from film production companies, distributors or producers, is now financing the production of films in exchange for those rights. About 30 such titles currently are in production, Peisinger said.

The most successful of those projects, which analysts and Peisinger agree ''put us on the map,'' has been ''Making Michael Jackson's Thriller.'' The 60-minute film has sold more than 1 million copies.

''Making Michael Jackson's Thriller'' was a joint venture of Vestron, CBS- Fox and Showtime in which the three companies financed Jackson's highly successful, 14-minute music-video, ''Thriller,'' then produced a film showing how it was made.

''Making Michael Jackson's Thriller'' accounted for $1.4 million, or almost 12 percent, of Vestron's 1984 revenues.

At Time, Furst had been president and chief executive officer of Time-Life Films Inc. His last job, Time spokesman Lou Slavinsky said, ''was to sort of wind down Time-Life Films'' after Time decided to concentrate on cable and pay television.

Peisinger said Time did not look at the Time-Life video rights given up to Vestron as having much value.

''The attitude then was that video was a promising business but it would take time to get there,'' he said. ''For an entrepreneur like Austin to leave the corporate fold and strike out on his own, it was worth it.''

Furst said he had become frustrated at Time and that prior ''distant thoughts that it might be a fun thing to do'' lured him away.

''I was running a division that one day had a mandate to grow with hundreds of millions of dollars to apply to it and the next day no dollars and hundreds of surplus people,'' he said.

''I have always believed there would be a good-sized home video industry,'' Furst said. ''But Vestron was at least two years old before the scale of this thing became real to me. I always thought of us as a scrappy independent that in a good year might be eighth or ninth or tenth.''

Peisinger said the prospect of being that ''scrappy independent'' was Vestron's early allure.

''We looked at that,'' he said. ''In the record business, you always had a few feisty independents nipping at the heels of the biggies. We looked at that as an opportunity to fill the void. I don't think anyone expected us to become one of the major players.

''What set Vestron apart was that here was a feisty independent with the resources to play with the big boys, that was aggressive in marketing and acquisitions and that said, 'This is the only activity we're going to be in.'''

At Time, Slavinsky said the company did not regret Furst's success.

''At the time, HBO (Home Box Office, the pay cable channel owned by Time) was taking off. Do you go with a business that's proven or do you take a chance?'' he said.

''I don't that we were capable of doing what he did. That was his idea.''

End Adv Weekend Editions Dec. 21-22