Those pumps are awful. If you get an air bubble in the line or need a small amount you risk messing up the ratio and having a poorly cured batch. Plus the har

Those pumps are awful. If you get an air bubble in the line or need a small amount you risk messing up the ratio and having a poorly cured batch. Plus the hardeners react with the air so if its been sitting a little while the first part of your pump is bad hardener. Highly recommend everyone use a scale.