Mixers

Cement mixers are an on-site mixing tool used to mix materials to form mortar or concrete. They usually have a tip-up mechanism making it easier to pour the mix onto a spot board or into a wheelbarrow. Small electric cement mixers are available but larger mixers are usually petrol or diesel driven. Cement mixers are used for creating manageable amounts of cement for reasonable sized jobs such as building a wall or laying a concrete base. Major projects needing large amounts of concrete will need a ready-mix lorry.

Small cement mixers usually comprise of three parts:

The stand - a base that raises the mixing drum to operational height.

The stand pivot - slots into the top of the stand to support the drum and turns 360°.

The mixing drum - the container in which materials are mixed.

• A cement mixer should always be positioned on firm, level ground.
• Never overload a cement mixer. The maximum capacity will be specified in the manufacturer's instructions.
• Rinse out the mixing drum with water to remove any debris before loading it.
• Use a shovel to load the materials in the required ratio into the mixing drum. Do not let the shovel enter the drum.
• At the beginning of the mix do not add too much water.
• Always allow time for the materials to mix thoroughly.
• When the mix has reached the correct consistency, pour it onto a spot board or into a wheelbarrow while the mixing drum is revolving.
• When pouring the mix into a wheelbarrow do not let the lip of the mixing drum come into contact with the wheelbarrow.
• When mixing is finished clean the mixing drum thoroughly. 

• Always follow the manufacturer's instructions.
• Petrol or diesel driven cement mixers should never be used in confined spaces. Always ensure there is adequate ventilation.
• Never put your hands or head in the mixing drum while it is revolving.
• Electric cement mixers should be unplugged before cleaning the drum.
• Keep all tools well away from the mixing drum while it is in operation.

An electric tub mixer works on the same principle as a cement mixer but is smaller, lighter and more manoeuvrable. The mixing container is a large plastic tub that is easily removed for cleaning.  Tubs vary in size but an ideal volume is around 65 litres (approx: 14 ½ gallons).

The underside of the lid of the tub has a shaft projecting through its centre to which the mixing blades or paddles are connected. Connected to the top of the lid is the electric motor which drives the shaft. The support stand is hinged, so as the motor is pulled back the lid is removed from the tub along with the mixing paddles.

Tub mixers can be used to mix a wide range of materials including plaster, mortar, paint and adhesive. The mixing process will depend on what is being mixed, but as an example here is how to mix plaster using a mixing tub.

• Pour the correct quantity of water for the required mix into the tub.
• Close the lid and switch the mixer on.
• Shovel plaster powder onto the lid which will now be rotating.
• As the lid rotates, the plaster will be distributed evenly into the tub from the lid edge and the rotating paddles will mix it with the water.
• Continue the process until the correct amount of plaster has been added to the water.
• Let the plaster and water mix thoroughly.
• When satisfied the mix is at the correct consistency, switch off the power and disconnect from the mains.

The tub mixer offers two main advantages over other types of mixers.

• As the mixing paddles are enclosed in the tub this method is safer than a cement mixer or handheld power stirrer/mixer.
• The wheels on the support frame allow you to move the mix to another location without pouring it into a wheelbarrow.

• Fit the stirrer into the chuck and tighten. Remember to remove the chuck key. 
• Submerge the mixing spiral or paddles into the material you want to mix before switching the drill on.
• Mix the material at slow speed. Mixing too fast will result in the material splashing from the bucket or paint tin.
• Switch off the drill before removing the mixing attachment from the material.