Fred Pons has knobby knuckles and the coarse hands of a jack-of-all-trades handyman.

The El Sobrante resident is a house painter, but when he’s not painting, he does odd jobs like landscaping to make ends meet.

Landscaping is how he got the spider bite this summer.

He was bitten on a Wednesday evening as he cleared wood chips from a yard in Berkeley. His hand and forearm swelled so that he looked like Popeye after scarfing down a can of spinach. He felt as if his hand was under a heating lamp. And he had a fever.

But instead of going to the emergency room, Pons gambled with his health. He has no health insurance and was afraid he’d struggle to pay any medical bills if he sought emergency help.

So, he waited until Friday morning to get medical help.

That’s when he went to the Order of Malta Clinic of Northern California, a free clinic in Oakland that’s open Monday, Wednesday and Friday for walk-ins, and Tuesday for appointments.

“I live on the edge as it is,” he told me when we met at the clinic. “I know (the emergency room) would’ve admitted me right away. I did everything I could to avoid that.”

Pons, 55, is one of 25,000 patients who’ve relied on the Order of Malta Clinic. The nonprofit health center is in the basement of the Roman Catholic Cathedral of Christ the Light on Harrison Street near Lake Merritt. Since the 11th century, the mission of the Order of Malta, a lay religious group, has been to take care of the sick and poor. It opened in Oakland in 2008.

When you walk into the clinic, a receptionist asks one question: “Do you have insurance?” If the answer is no, the patient isn’t turned away.

At the clinic, health care is treated as a right.

The Malta Clinic doesn’t take payment for services, and the clinic accepts anyone, regardless of race, religion or immigration status. People go to the clinic for regular checkups, and treatment for diseases such as diabetes and conditions like high blood pressure.

Except for the receptionists and a few nurse practitioners and doctors, the clinic is staffed by volunteers. On a recent tour of the clinic, I met Francisco Javier Diaz, who wore a white lab coat over a black shirt with a clergy collar. Downstairs he’s Dr. Diaz, a family doctor. Upstairs, he’s Father Diaz, a Jesuit priest.

The clinic also uses residents from Kaiser Permanente who are training in clinical medicine, and it has a partnership with UC San Francisco’s nurse practitioner program.

“This place is like volunteer city. It’s wonderful,” said Vona Lorenzana, one of the few doctors who are paid. “There are people who fall between the cracks, and we’re here to serve.”

The clinic is privately funded through donations, an annual fundraising dinner and corporate grant money. It costs $550,000 to operate the clinic yearly, according to John Christian, the clinic’s board president. Because the clinic partners with vendors such as Quest Diagnostics, the clinical laboratory provider, it’s able to pay for lab tests. The only thing the clinic doesn’t cover is prescriptions.

But sometimes they find ways even then to help.

Last year, the clinic treated Pons for hepatitis C, a virus that affects the liver. It was the first such case the clinic handled, and the staff worked with a medical provider to get Pons a free prescription of Harvoni, the expensive antiviral medication with a high cure rate. Without insurance, Pons would’ve paid about $1,000 pill — or about $84,000 for a typical 12-week treatment cycle.

After four weeks taking Harvoni, the virus was undetected in Pons’ blood. Without Order of Malta, he’d still be suffering stomach pain, nausea and fatigue, the symptoms associated with hepatitis C.

For the spider bite, Pons took antibiotics — two different prescriptions — for three weeks. All that remains from the bite are pink dots between his thumb and forefinger.

“Trying to find ways to get health care taken care of, sometimes it’s a little rough,” he said as he rubbed his hands. “But with the Malta Clinic, whatever they can provide they provide.”

San Francisco Chronicle columnist Otis R. Taylor Jr. appears Mondays, Wednesdays and Fridays. Email: otaylor@sfchronicle.com Twitter: @otisrtaylorjr