Our smallest concrete mixer can hold half a bag of concrete, and our largest 9 cubic foot mixer can hold 1 1/2 to two bags. Our 6 cubic foot mortar mixer can hold 1 1/2 to two bags. Alternatively, mortar mixers are capable of holding more than a concrete mixer.

Both mortar mixers and concrete mixers will use bags of cement. The difference is that mortar contains a smooth aggregate, like sand, and concrete mixes have a larger aggregate, like gravel. Mortar mixers are specifically designed for mixes that have smooth aggregate, and using gravel aggregate made for concrete mixers can damage the blades of a mortar mixer. United Rentals offers concrete mixers for rent that can handle this tougher aggregate to create a suitable concrete mix.

In short, yes, you can mix mortar and concrete. Mortar is composed of cement, fine sands and lime. Concrete is composed of cement, sand and larger aggregate such as gravel. Adding rough sand or other aggregates to the mortar mix will turn the mortar into concrete, similar to what happens when you mix mortar and concrete mixes together.

Keep in mind that some concrete bags are sold pre-mixed with aggregate, so all you need to do is add water. Pre-mixed concrete bags are best for beginners. To prepare a pre-mixed bag, empty the bag of concrete into the concrete mixer and spray it down with a little water to keep down the dust. Turn on the mixer and slowly add water from a hose or bucket until you reach the desired consistency. Ideally, the concrete should be wet enough that when you grab a handful it will stay together and not fall apart, but it should not be runny either. For more help, contact your local United Rentals.