Original Radiators

I'm not a big fan of taking radiators to radiator shops... I have a friend I think he's pushing into a 70s now but his first job was partners at a radiator shop and just to make sure they never came back they'd drop a small block of that stop leak in just before it left the shop...
I've heard the stories were areas are just plugged off to stop the leaking...
For what an aftermarket aluminum radiator cost these days I wouldn't even think of it...