The drum is turned by means of a handle at the far end of the frame
Compost tumblers are available in three basic forms.
- The Rotating Barrels,
- Tombola drums.
- Rolling Drums and Balls
I have found that the speed of decomposing varies with the type of tumbler bin
as in practice the ease of rotation (see above) will play a major part in determining the frequency with which the bin is turned and aerated once the novelty of having a new bin wears off. At the Compost Corner the Snibston Demonstration site, we have
found that the barrel type of bin can be quite heavy to turn when in use which means that people do not turn it! On the other hand, the Jora “tombola” style is very easy to turn and is spun regularly by small children.
Barrel shaped Tumblers
These consist of a vertically mounted barrel or drum which rotates on a central, horizontal metal axle. The axle is mounted on a metal, wood or PVC frame. As a rule the plastic drum is made
out of recycled plastic but at least one company reuses drums which have previously used by industry thus saving the energy which be used in the recycling the plastic in. When the bin is turned and the contents tumble inside the bin the central axle breaks
up and mixes the contents. It is worth checking that the lid is correctly in place before spinning the bin.
In my experience the older bins of this type are one most likely to be sitting in a corner of the garden neglected because the gardener
could not get on with it. Having said that I usually find that in a group of 50-100 gardeners in a Garden Club there will be one or two who get on really well with this type of bin and use them to produce compost quickly and efficiently. One of the gardeners
also report success in using this type of bin to produce leaf mould in the autumn.
It is also a good idea to save the compostable material and fill the bin all in one go (batch composting) as the compost needs to be at the same stage of decomposition,
as it will all be tipped out at the same time. While Barrel Tumblers are neat in appearance and resistant to rats and other pests do consider the storage of the material prior to composting and while it matures at the end of the tumbler process.
different makes of tumblers are mounted at different heights and if possible, it is better to get one that can be emptied directly into a wheelbarrow, otherwise they can be empted onto a sheet of polythene and contents shovelled into a barrow.
A horizontally mounted drum rests on a raised framework and look like a large tombola drum. The drum can be either free spinning or Crank-operated. In the later case,
a crank assembly is provided to turn the drum relatively easily but this may be slower than the free spinning models. The drum may consist of a single or double chamber, and will normally have internal baffles help mix the materials. With the twin-chambered
models, material can be starting the maturation process in one chamber while fresh material is added to the other. However, a separate maturation bin is recommended for maximum production and to make best use of the speed at which the material is broken down.
They may have sliding or hinged doors.
The Mantis range are examples of this type of bin sold for garden waste .http://mantis.uk.com/mantis-compostumbler-comparison.asp
The Jorra range is available for cooked food waste are currently available from Smartsoil but the company is closing down. Some composters are still available (Dec 2015) at reduced prices http://www.smartsoil.co.uk/
The drums are mounted on a frame and this needs to be of a height that will enable a wheelbarrow to be placed under the drum and the compost emptied directly into it. Some models are supplied with frames for wall mounting.
Base rolling drums.
Round or horizontally shaped drum design to be rolled on a ground-level base quite widely advertised. Depending on price and style, these may be mounted on rollers,
or have moulded raised points to suspend the drum so that it can rotate on the base. The type with rollers in the base require less effort to turn.
Depending on the size of the composter, it may be necessary to bend to turn it and emptying has
to be undertaken using a spade. These are often sold for smaller gardens. However if the drum can be rolled of its base it can then be rolled to the part of the garden where the compost is required.
Sphere or Barrel Compost Tumblers.
The commercially available models of which I am aware are large shaped “balls” that are rolled around the garden to mix and aerate the compost. They tend to be difficult to steer and to
empty. It is possible make a roll-around barrel composter using an empty chemical drum, drilled with air holes and fitted with a secure lid. An example of such a bin is shown on the "Demo Site" page