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Hypertufa

Hypertufa is a cast “rock-like” material which can be used to make relatively inexpensive pots for the garden and to coat old sinks. It looks like rock, can be cast into almost any shape, is very lightweight and also strong enough to withstand the freeze/thaw cycle of most northern climates.

Apparently some people get totally hooked on hypertufa and fill their own gardens, their neighbours gardens and anyone they can think of’ gardens with these wonderful creations. My bad back said ‘very pretty sonny but you’re not making any more’.

A variety of recipes are available based on the following ingredients:

Cement: Dry Portland cement
Sand: Sharp concrete sand for preference
Peat: Peat moss, sifted to remove larger lumps and foreign objects
Perlite: “Normal” garden variety perlite, sifted to remove larger lumps.
Vermiculite: Pure vermiculite. Many seed starters also contain some kind of compost and/or peat mixed in. This will not work!
‘Fibremesh’: “Shredded” fibreglass fibres (to add strength)
Concrete Dye: (optional)

All of the following mixtures are used the same way. Mix all of the dry ingredients well, and then slowly add water until you get a thick “mud pie” texture. A mould can be made from two wooden boxes the inner box about two inches smaller than the outer to get a minimum 1 inch gap for the mixture. Mixture is poured into the bottom of the bigger box to a depth of 1″ or so, the smaller box is then placed on the mixture and the remaining hypertufa rammed down the sides to make the walls of the container. Applying cling film or plastic bags to the walls of the boxes helps when you come to take the creation out of the mould. Leave to cure. Curing can take 1 to 2 months! After it cures, you can rough it up with a wire brush, or cut it with a saw. Add drain holes as required using a screwdriver or drill. If you want a rough finish, you may need to “melt” any exposed fibreglass using a blowlamp or a candle.

Blends

Basic
1 part cement, 1 part sand, 2 parts peat
Variation 1
1 part cement, 1.5 parts sand, 1.5 parts peat
Variation 2
1 part cement, 1 part peat, 1 part perlite, 1 part fibermesh
Variation 3
1 part cement, 1 part peat, 1 part vermiculite
Variation 4
1 part cement, 1 part sand, 1 part peat

I have only ever used the first mixture and that was to coat a couple of old sinks. Having made the mixture to the consistency of a stiff squidge (OK you try to describe it) or to cake bakers a ‘dropping consistency’ the whole sink should be coated with PVA adhesive and allowed to go tacky. The hypertufa mixture is then clagged on in handfuls (wear a glove – cement is nasty) forming a layer about ½ inch thick all round the sink. Allow to set overnight then wire brush to give a satisfying rustic finish.

The advantage of adorning an existing container is that it is ready for use within a few days. We acquired two very convincing ‘stone’ sinks after a couple of years of lichen growth then stupidly left them when we moved house. We now have two more old sinks – anyone for hypertufa?

David Booth.