Once packed, the cans were weighed to ensure that they were properly filled. Initially each can was weighed using a hand scale. Underweight cans were sent to the patching tables where workers would top them up, or patch them, with smaller pieces of salmon. Overweight tins were also corrected to avoid faulty sealing or exploding during the cooking process.
By the 1920s a mechanical weighing machine had replaced the hand scales. It was faster and more consistent than the manual method. The machine would detect underweight cans and eject them to the patching area. Once patched, the cans were put on a conveyor and returned to the main line.