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Hypertufa

Hypertufa is a mixture of materials used to make a substance similar to the natural volcanic rock called Tufa.

Since most Tufa deposits have been depleted Hypertufa mixtures are becoming more and more popular.

Tufa is much lighter than stone or concrete, and can withstand extremes of heat and cold.

It is formed by mixing sand, peat, various aggregates with cement.

The resulting mixture can be moulded or carved into vitually any shape that you want, for example; garden troughs, rocks and boulders for forming rockeries, and stepping stones for the lawn.

The more adventurous gardener may even attempt items such as gnomes, miniature windmills, the ideas are limitless.

Basically anything that can be made with concrete can be made with Hypertufa.

However! For your first project it may be best to start out with something simple, such as a boulder or a stepping stone.

The first thing one must get used to is the viscosity of the wet mixture, too wet and it may not mould into the desired shape, too dry and it may be difficult to work with.

The moisture content will also affect the drying period (curing) and hardness of the finished product.

Tools:

A measuring container/bucket, a hand trowel, water bucket and mixing bowl or bath, moulds.

Material:

Subject to the look required on completion, this mixture can vary, but basically it is as follows;

Portland cement is the binding ingredient that holds the resulting product together.

Building sand, will produce a smooth finish whereas sharp sand will give a more porous grittier finish.

Playing about with varying ratios of these products will give varying textures.

Plus adding Peat moss, perlite, or vermiculite in varying amounts, will also produce different surface textures.

Similarly, concrete dyes can be added to the mix at the described amounts stated on the packaging to add colour to your end result.

Moulds;

Purpose made rubberised moulds can be purchased from specialist shops if necessary.

However, if you want to get that rustic look, a box of sand should suffice.

Method:

Fill the box with damp (not too wet) building sand*

* This type has a texture that remains intact after forming the desired shape, some other types of sand may be less cohesive and make carving difficult.

Carve out or press an object of a desired shape into the sand and form a depression, then pour your tufa mix into this.

Allow the mix to set for a day or two before carefully lifting it out of the sand.

Care is paramount at this stage so as not to disturb the moulds shape, particularly if more samples of the same shape are required.

In the event that the mould does crumble, you can press the first sample into the sand to form the mould for the next and succeeding examples.

Brush /wash off any sand that is adhering to the finished product/s.

Rockery stones:

If making rockery stones you can form fissures in the blocks / stones into which you can embed tiny rockery plants.

Method:

When the depression has been formed insert pieces of thin polystyrene in the desired position of the fissures prior to pouring the tufa mixture.

Then when you remove the finished product from the mould, the polystyrene can be scraped from out of the tufa stone after it has hardened to leave the desired fissures.

Covering an old Ceramic sink:

Old ceramic sinks can be converted into stone like troughs for use as alpine and or miniature gardens.

Preparation:

Clean the sinks thoroughly, chip the glaze on the exterior of the sink, then coat the surfaces to be covered with hypertufa with a p.v.a. bonding agent to ensure good adhesion.

The mix:

Measure out 4 parts (by volume) sifted sphagnum moss peat, 1 part coarse sand, and 2 part cement.

Then mix the ingredients thoroughly whilst dry then add water.

Mix thoroughly until the mixture is the consistency of plaster.

Application:

Trowel the tufa mix onto the sides of the sink after the p.v.a. has dried.

The surface can be textured to your own requirements, e.g. smooth, scalloped, or serrated/scratched, the choice is yours.





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