A concrete mixer rental is a rotating drum on a stand or a tow frame that mixes cement, aggregate and water on site. Electric portables of 3 to 9 cubic feet run about $40 to $90 a day; towable gas mixers are larger and dearer. The useful question is not which mixer, it is whether you should be mixing at all above roughly one cubic yard.
Drum size is not batch size
A drum rated at 6 cubic feet mixes about 3 to 4 cubic feet of concrete, because it needs room to tumble. That is roughly two 80-pound bags a batch. Work out your total volume, divide by the real batch size, and you have the number of cycles somebody is doing by hand before the first pour goes off.
Where ready-mix takes over
Around a cubic yard, a delivered truck usually wins on both money and quality. A yard is about forty 80-pound bags, which is roughly a dozen batches of mixing, carrying and placing while the earlier concrete is already stiffening. Short-load suppliers will bring part loads, and a consistent mix beats twelve slightly different ones.
Electric or gas, portable or towable
Electric mixers are quieter, run off a standard outlet and suit a patio or footing near the house. Gas towable mixers handle bigger batches and sites with no power, and need a hitch and a light connection to move on the road. Both want a level standing spot and somewhere the wash water can go.
Cleaning and what it costs to skip
Hose the drum out at every break and again before it goes back. Set concrete in a drum is the single most common extra charge at a tool counter, and chipping it out is worse than the twenty minutes of rinsing that would have prevented it. Dispose of wash water where it will not run into a drain.
Questions people ask about concrete mixer rental
How many bags fit in a rental mixer?
A common 6 cubic foot drum takes about two 80-pound bags per batch and mixes them properly. Loading a third to save a cycle produces a badly mixed batch and puts the load on a motor sized for two.
Should I mix or order ready-mix for a shed base?
A small shed base under about half a yard is a comfortable mixer job. Past a full yard, order it. The cost difference narrows quickly once you count bags, a helper's day, and the risk of a cold joint between slow batches.
Can I tow a mixer with a car?
Small towable mixers are light, but you still need a hitch rated for the load and working lights. Many yards deliver them for a modest fee, which is usually the simpler answer for a one-day pour.