Harbor Freight has a solution for those who use two-part epoxy glue and find the four ounce and six ounce containers’ contents become unuseable after time. Yes, the hardner gets gummy over time. Harbor Freight sells the catalyst hardner and resin in two small tubes with screw tops for 2.50 a package. Watch for their frequent sale at 1.95 per pack. I have had tubes that were opened, used half, and they still are both useable after 4 months. The tube screw cap works tightly.
Wendell