What volume of mortar requires hand mixing according to the guidelines?

According to standard masonry guidelines, hand mixing of mortar is typically recommended for smaller batches. When the volume is less than a certain threshold, such as 6 cubic feet, it is practical to mix by hand to ensure a consistent blend and maintain control over the mixing process. Small batches allow for easier management of materials and prevent waste, while ensuring that the mortar can be used quickly before it sets. This practice is particularly important on smaller job sites or repair tasks where larger mixers may not be justified or feasible to transport. In contrast, larger volumes usually necessitate mechanical mixing for efficiency and consistency, making option B the most accurate choice regarding the maximum volume suitable for hand mixing.