Boat Building with Epoxy – All epoxies come as a resin and a hardener, mixing the two together sets of a chemical reaction turning the epoxy mix into a glue which cures after a certain amount of time. There are many companies manufacturing epoxy, each having their own ratio for resin to hardener mix, typical examples are 5:1, 3:1, 10:3. Accurate measurement is critical.
Pump or Scales – Some manufacturers supply pump dispensers to ensure the ratio is correctly metered out and others require digital scales for weighing the resin and hardener. Both systems have their advantages. Pump dispensers are easy to use, but small quantities are difficult to achieve and the pumps can form air-pockets, affecting the quantity dispensed. Scales can be awkward to use as you need to have a steady hand and good math skills, but on the plus side you can mix as much or as little as you like. A combination of the two will give you the best of both, but at additional expense.