All System Three® epoxy products can be measured by weight or volume. Pourable products can easily be measured by volume, but paste and putty products are most accurately measured by weight. The correct mixing ratio for your product can be found on the product page.
To measure by volume:
Dispense from the plunger pump or pour the Part A (resin) into a graduated mixing container, then pour the Part B (hardener) directly on top of the resin. Example to mix 3oz of a 2 parts resin to 1 part hardener product. Pour the resin (part A) up to the 2oz line, then pour 1oz of hardener directly on top of the resin bringing the total volume to 3oz.
Using a disposable stir stick or paint paddle, stir the liquid vigorously, then scrape the sides and bottom of the container. Generally, it should take no longer than 2 minutes for a larger 1-quart batch. You will notice when initially mixing the epoxy that the appearance is cloudy. As the material becomes better mixed, the cloudiness begins to disappear. When the mixture is clear, the epoxy is fully mixed. Of course, the larger the batch, the longer it will take to fully mix.
PASTE AND PUTTY
To measure by weight:
For epoxy paste, measure out the correct ratio of Part A (resin) and Part B (hardener), using a paper plate or cardboard scrap on a gram or postal scale. Mix together using a mixing stick or spatula until the material achieves a uniform color.
For epoxy putty, measure out the correct ratio of Part A (resin) and Part B (hardener). Wearing disposable gloves, mix by hand rolling and kneading the epoxy until an even color is achieved.
For a more detailed description of measuring and mixing, see this section in The Epoxy Book.