A mortar mixer is a horizontal drum with turning paddles, built to fold sand, cement and water into a plastic mud rather than tumble stone. Rental centers keep them from small electric units up to towable gas machines, and the useful question is not the price but how much mud your masons get through in an hour.
Size the drum to the masons, not to the wall
A mixer is sized by batch volume in cubic feet, and a bricklayer working steadily empties a small batch faster than most people plan for. One mason can be supplied by a small unit; two or more want a 9 or 12 cubic foot machine. Undersizing means the wall waits for the mixer all day.
Paddles fold, drums tumble, and the mud knows
Mortar needs shearing and folding, which is what the paddles inside a fixed drum do. A rotating concrete drum relies on gravity and will not properly wet out fine sand and lime. Hiring the wrong one produces mud that looks mixed and works badly under a trowel, which is a slow, expensive discovery.
Gas engine, tow hitch and where it stands
Bigger units are towable, run on a small gas engine and want a flat spot near the sand pile and the water. Electric units suit indoor or noise limited work but need a supply the site can carry. Confirm the hitch and lighting arrangement if you are towing it yourself, and whether the yard will drop it instead.
The deposit rides on how it comes back
Set mortar inside a drum is the classic extra charge on this hire. Wash the drum and paddles out at every break rather than at the end, and never leave a loaded mixer standing in the sun. Ask the counter what cleaning condition they expect at return, because that answer varies between yards.
Questions people ask about mortar mixer rental
What size mortar mixer do I need for a block wall?
For one mason working alone a small drum keeps pace. For a crew of two or three laying steadily, a 9 or 12 cubic foot machine is the sensible hire. Tell the counter how many people are laying and they will size it faster than a volume calculation will.
Can I mix concrete in a mortar mixer?
You can mix small amounts of fine mix, but stone and heavy aggregate wear the paddles and rubber blades and can jam the drum. Yards generally ask you not to, and some charge for the damage. For concrete, hire a tumbling drum mixer instead.
Is it cheaper to hire by the week?
Nearly always. The weekly figure is discounted against seven single days, so any job running past a couple of working days is cheaper on a week. Check the early return policy before signing, since some centers refund unused days on a long hire and others do not.