Huge mounds of Gillette Foamy shaving cream are not thick enough to stop a roller coaster or a speeding race car, as the company's television commercials admit.
But far smaller quantities of the stuff do stop teams of Gillette's own employees in their tracks every day.
At designated times, 250 to 300 unshaven volunteers troop into cubicles at the company's Shave Test Center in South Boston. They lather up with shaving cream, take the company's various types of razors in hand, and proceed to scrape off their whiskers.
The experience is over in minutes, and the subjects - from executives on down - return to their regular jobs. But during the testing, technical experts stand by recording results and observations: How close was the shave? Was it comfortable? Were there any nicks or cuts?
The objective, says Gillette spokesman Greg Niblett, is ''to make sure that our existing products remain state-of-the-art.''
For good measure, the competition's products are put to the test at the same time. Often, says Mr. Niblett, the participants do not know whose products they are using.
Gillette, which claims to have a 60 percent share of the shaving market, is only one of many companies that use employees to test the consumer goods they produce. This is despite the fact that those same products usually are submitted to careful scrutiny in the company laboratory, too.
''We feel the final test is consumer satisfaction,'' Niblett says. ''It would be foolish not to test.''
Walter Blanck, assistant director of product management for the Association of Home Appliance Manufacturers, whose members widely use such testing, says: ''When you enter the human aspect into the use of the product, you're putting in entirely different parameters than you do in the laboratory.''
In a laboratory a product has to perform at the optimum, Mr. Blanck says. ''If it's a washing machine, the engineers will weigh out exactly 18 pounds of clothes and stuff them in. But consumers don't know how much 18 pounds of clothes is. They'll put in whatever they have to wash; they'll mix types of fabrics. What they report back gives the engineers a chance to correlate what's happening in the field with what they found in the lab. Over the years, you're going to accumulate an awful lot of data.''
Companies that manufacture a range of products often place their top-of-the-line models in the homes (or offices, or cars, or boats) of their senior managers as an executive ''perk,'' say people familiar with the practice. Volunteers among employees usually are sought to test ''down scale'' products. But no matter what the employee's status, he or she is usually expected to use or wear the product for a specified period of time and submit regular reports on its suitability and performance.
Ultimately, the tester may be required to return the product so laboratory analysts can take it apart for detailed study.
Eastman Kodak handpicks employees to test new products, such as its disc and instant cameras, says company spokesman Henry Kaska. In fact, the company tries to make sure its test ranks include ''left-eyed'' and left-handed people, as well as those whose right side is dominant.
Mr. Kaska says the program has helped company designers decide where to place camera buttons and how to avoid such errors as accidentally placing a finger over the lens while shooting.
There are product areas that do not lend themselves to testing by employees, however. Firestone, for example, uses only technologists to measure the performance of its new tire designs because variables in ride or tread wear can be too subtle for the average driver to detect, according to spokesman Bob Troyer.
The practice of using lay employees as ''guinea pigs'' is not without its critics. At best, it is a ''limited method,'' claims Frederick Schlink, technical director of Consumers Research in Washington, N.J.
Employees without a technical bent are ''not likely to be good critics because they don't want to make anybody mad,'' Mr. Schlink says. ''They may make some comment about the markings on the dial,'' but otherwise ''wouldn't know (a product) wasn't good.''
To conduct a testing program properly using its own employees, he says, a company should ''send out enough of (its products) so that they'd catch the statistically probable rate of failure.''
Schlink puts that rate at 1 unit in every 10.