The expo has been traveling the country for a decade, preaching disaster readiness and appealing most recently to worries that Y2K and the coming millennium will change life as we know it - and not immediately for the better.
For $8, visitors will be able to browse among 200 vendors selling radiation detectors, tents, and a two-year supply of rations.
They can learn how to evade income taxes and make their own license plates.
Lectures will be offered on such topics as "Trapping Techniques for Self-Reliance and Survival," "Don't Get Caught With Your Pantry Down," and "Save Your Life, Be Your Own Doctor." Three seminars are about life under martial law.
And for a little extra cash, visitors can hear 65 featured speakers, including militia leader Bo Gritz, talk about coming plagues, food shortages, and how President Clinton has sold out America.
Critics say the expos have become staging grounds for some groups to recruit followers to antigovernment militia and survivalist causes that spread paranoid ideologies fueled by anti-Semitism and racism.
"It's not just about preparing for an emergency or disaster: What they're selling is a whole world view - a program for the apocalypse," said Stephen D. O'Leary, a communications professor at the University of Southern California who studies beliefs about the millennium. Potok, who is based in Montgomery, Ala., and has visited the expos, said that "it's not unusual to see booths for the John Birch Society and the Montana Militia next to a granola salesman."
Such events, he said, offer right-wing groups a chance to fuel hysteria about the millennium, which they believe will mean loss of civil liberties and race wars. The radical right, Potok said, is using Y2K to fan fears about what might happen if computers worldwide crash as they confuse "00" for "1900."
Most scholars agree the millennium refers to Jan. 1, 2001. But many groups espousing millennial beliefs - and much of the public - look at Jan. 1, 2000, as the Big Day.
Chittock has one word for the critics' concerns: "Nonsense."
"They've got agendas of their own," said Chittock, whose expo is visiting the Philadelphia area for the first time. "The shows are a forum for different political and religious perspectives."
David Kessler, executive administrator of the Center for Millennial Studies at Boston University, said: "Y2K's cause is so mundane that it allows people who would never buy into any apocalyptic scenario to take notice."
Such groups as the American Red Cross and the International Association of Emergency Managers in Falls Church, Va., representing 1,700 emergency management coordinators, urge preparedness for Y2K, but with less drama. They advise the public to store enough food for a week, keep a gallon of water a day per person, acquire a 30-day supply of prescription medicines, and save bank and other financial statements.
Elizabeth Armstrong, the association's executive director, said she thought consumers might pick up useful tips at the Preparedness Expo, but she cautioned against buying into disaster scenarios.
"It's dangerous to alarm the public needlessly," she said. "Government and private industry have spent years and invested millions in preparing."
The Eastern Pennsylvania and Delaware chapter of the Anti-Defamation League plans to send observers to this weekend's expo, said regional director Barry Morrison.
"What we're concerned about is that some people take the position that the government is not to be trusted," he said. "Some of these exhibitors . . . portray people like Jews in an unfavorable light and as having undue control over their lives."
According to an ADL report, material at recent expos in Orlando and Denver included anti-Semitic tracts including literature from Christian Identity - a movement that depicts Jews as devils and ethnic minorities as inferior.
Gritz, a former Green Beret, has called AIDS a federal conspiracy to control population and has served on the advisory board of the Liberty Lobby's Populist Action Committee - a group that the ADL calls "the most influential anti-Semitic propaganda organization in America today."
"I'm not saying everyone there is an extremist or subscribes to those views," Morrison said, "but this is a vehicle that attracts that element. It's part of the mix."
The expo has visited Sacramento, Dallas and Kansas City so far this year, and after Philadelphia has stops planned in Tampa, Minneapolis, North Carolina, and Denver. Chittock said he expected 4,000 to 6,000 to attend the Fort Washington expo.
A show calling itself the "Preparedness Expo" visited Philadelphia in July 1997 but was organized by an Ohio-based promoter. Chittock called that show "a cheap knock-off" of his own.
Kessler, of the Center for Millennial Studies, said Y2K was the secular embodiment of the millennial belief that there is a better world beyond the everyday and that a radical transformation is needed to get there, and of the apocalyptic belief that drastic change is imminent and you have to prepare now. Such beliefs exist in nearly every culture, he said.
"People have been saying for thousands of years that the world is going to end, and so far they have all been wrong," Kessler said. "But that does not extinguish the power and influence they have on history."