Peel and slice cucumbers 1/2" thick. Create ring by cutting out middle with melon baller. You will need 1/2 gallon of rings.
In a large pot, combine 1/2 cup pickling lime with 2 1/8 gallons water. Stir until fully combined. Add cucumbers and soat for 24 hours. Drain and rinse well. Return cucumber rings to pot.
Combine 1/4 cup vinegar, 1/4 Tbsp alum and red food coloring, if using. Add to pot with cucumber rings. Then, add enough water to cover the cucumbers. Bring to boil and then simmer for 2 hours. Drain and discard liquid.
In a large pot, heat 1/2 cup vinegar, 1/2 cup water, 3 cups sugar, 3 cinnamon sticks and 1/2 cup red hots, stirring until sugar is fully dissolved. Turn off heat and add cucumber rings. Cover and let sit 2 hours.
Transfer cucumber rings to jars. Add liquid about half full. Store in refrigerator or follow directions for preserving in jars.
1) I did not use food coloring in my recipe. It is optional.
2) The original recipe calls for letting the pickles soak in the final liquid overnight. Then, reheating the liquid and soaking again for another night. On the final morning, the liquid and cucumbers are reheated and then preserved in sterile jars.