"I made my first donation in April of 1979 while I was working at IBM," he said. "They came in with a drive and I thought, 'What the heck?'"
Last month, flint donated his 155th pint of his A-positive blood -- which translates to 19 gallons.
"That's dedication," said Mike Parejko, executive vice president chief executive officer for the Indiana Blood Center. "A unit of blood helps 465 patients, but think about the cascade of people who are impacted. Think of the family and friends (Flint) has impacted with his donations. All of those people who received the blood he gave were somebody's mother, daughter or son. It's just amazing."
Flint, 77, has been in Putnam County all his life. Since his first donation in 1979, he has given blood every time he was eligible to do so.
"I try to keep up on the schedule (of drives) they have at the churches," he said. "There have been times when I've been out of town when the drives here were going on, so I've gone to Terre Haute."
Flint took two donating breaks -- once in 2000 after a mild heart attack and once in 2005 after double knee replacement.
"I've probably lost about six months altogether," he said.
Flint has kept records of all his donations, and knows exactly when he can donate.
"You can give every 56 days," he said. "Unless you give red blood cells like I did last time, and then it counts as two units, so you have to skip a donation. You can't fudge on that even a little. Since I gave red blood cells in August, I can't give again until December."
Flint has two grown sons. One gives blood "occasionally," but the other doesn't have the stomach for it.
"The oldest … he's one of those wimps," Flint said with a chuckle. "He played all the sports, but when it comes to giving blood, forget it."
Flint's wife of 50 years, Carolyn, is a dedicated Putnam County Hospital volunteer, but blood donation isn't her thing, either.
"She gets a little queasy," Flint said.
Flint has been giving blood for so long it's becoming difficult for personnel at the drives to find good veins.
"Trouble is, now they're getting scarred," he said. "I try to alternate arms."
Blood shortages are beginning to be a problem in Indiana and nationwide.
"They're hurting for blood now," Flint said. "That's why I keep doing it."
One reason for shortages is that regular donors are getting older.
"Those very, very good donors are getting sick and some are dying," Parejko said. "Most of the blood that is transfused goes to people who are 60 and older, and those are the people we've always counted on. They're receiving now where they used to be giving. We have to shift now and find ways to attract Baby Boomers and Gen-X'ers, and then to retain them."
Parejko likened blood donation to Social Security.
"We have a lot of people taking out now and not a lot going in," he said. "If we continue on this path, we'll be at a deficit."
Flint plans to give blood until he's told he can't anymore.
"You get a drive for it and you just have to do it," he said. "I don't know how far a unit goes toward saving a life, but it's bound to help at least a little."