When choosing a used mortar mixer, pay attention to the condition of its frame rather than the mixer's general appearance. If you notice that the frame is damaged in any way, choose a different mixer. However, if the frame is in a good condition but the mixer doesn't look appealing, don't let that throw you off, as mortar mixers become dirty and covered in cement very fast.
When choosing a cement mixer, decide whether you need a smaller model or a large industrial mixer. If you need an industrial mixer, look into a possibility of renting one, instead of buying it. If you are buying a smaller mixer for personal use, pay extra attention to the frames of mortar mixers, as they are the most important parts. The frame of the mixer has to be well-constructed, preferably made out of reinforced steel.
Make sure that the wheels on the mixer are large and thick enough to handle muddy inclines and bumpy ground, as well as the extra weight provided by mortar itself. Try moving the mixer around in the store to make sure that it is steady and that its axles don't bounce. Mortar mixers have different drum sizes, so determine how much mortar you need the mixer to hold at once. Keep in mind that a mixer can only be two-thirds full.