Morning, I'm not familiar with 1018 but usually it's not a good idea to use expired resin. A few different things might happen with it, Sometimes you can get little balls of hard resin and crystals developing, sometimes it will look clear and normal but after you apply it then it always has a tacky surface even when cured. And sometimes it could cure great for about 95% of the area but one patch would stay wet like it never mixed with the hardener. You could get lucky and it turns out ok. If it's for structural work then don't touch it. If it's just for cosmetic things then do a test patch and see how it performs. I personally would throw it in the bin!!!