We buy our high quality 2:1 Marine Epoxy in bulk for use in our workshop and decant it just for you! If you are using it, we are using it! What we sell to our customers is (and always will be) from the same drum that we are using every day so we know it works. We have two hardener options "slow" and "fast". If you are working in a colder shop consider the fast. You'll still have about a half hour of working time. Or get a mix ( Eg. 3 gal kit with 1/2 gal of slow and 1/2 gal fast).
Be sure to check out our article on the basics of working with epoxy.