There are a few different ways that you can mix the two-part epoxy resin. Before mixing, you should figure out the correct ratio. Using the wrong ratio can result in improper resin and ruin your entire project. One of the best ways to mix two-part epoxy resin is to mix by volume instead of weight.  The density of hardener and resin may differ, meaning they do not have the same weight. This can affect your resin in the end if you measure by weight as your measurements will not be exact.  Another great way to mix two-part epoxy resin is in a temperature-controlled room. Having a room that is too warm or too cold may affect the way your resin sets. Controlling the temperature ensures your resin is set at the perfect temperature and sets the way you want it to.