Hypertufa How To

Hypertufa Glossary

May 8th, 2008 by Seb Brown

The following is a glossary of terms used when making Hypertufa. If you think there is something missing from the list please add a comment below.

Accelerator – Ingredient added to increase the hydration and to shorten the set and cure times.
Admix – See Admixture.
Admixture – Generic term for any non-bulk material added to Hypertufa. It is also an abbreviation for acrylic bonding admixture, which increases strength while reducing moisture absorption in Hypertufa.
Aggregate – Any dry bulk material added to Hypertufa other than Portland cement and sand.
Air Entraining Agent – An ingredient that can be added to a Hypertufa mix which captures miniature air bubbles during the mixing process. This reduces the harmful effects of freeze-thaw cycles.
Alginate – A one time use mould making material used primarily for body casting.
Armature– A “skeleton” or support structure for large Hypertufa projects.

Bug Holes – Small holes found in Hypertufa castings caused by air bubbles.

Casting – The end product of the moulding process.
Cement – See Portland cement.
Chicken Wire – A light galvanized wire fencing usually made with relatively large-sized hexagonal mesh. Can be layered around an armature to hold the Hypertufa mix in place and strengthen the structure.
Closed-Cell Foam – A hard, non-absorbent foam.
Compressive Strength – The ability of Hypertufa to to withstand a downward force or to sustain a heavy weight.
Concrete – A mix of Portland cement, sand and water. The standard construction recipe calls for one part Portland cement to three parts sand/shingle.
Concrete Admix – See Admixture.
Cure – The process by which Hypertufa hardens; dependent on sufficient hydration and temperature.

DWT – Drywall tape.

Efflorescence – Salts which leach out of Hypertufa during the curing process.

Faux Bois – Imitation wood (French).
Form – Mould used for setting the outside shape.

Grot – An Abbreviation of grotesque, They look like gargoyles but instead of being used as rain spouts they are used as planters.
Green – Uncured.

HWM – Hardware mesh, cloth. Used to reinforce larger Hypertufa projects.
Hydration – The chemical reaction between water and Portland cement.

Model – An original piece used to make a mould.
Mould – A rigid structure used to hold green Hypertufa into a fixed position until it sets. See also positive mould, negative mould, mother mould.
Mortar – A variation of concrete used in masonry; it does not contain rough aggregate.
Mother mould – Outer, often rough mould made of the back of a mould. Used to secure the mould during the casting process when it is made of flexible or fragileĀ  material.
Moulage – A reusable mould-making material that is used primarily for body casting.

Negative Mould – The casting of a model which is made to create a positive mould. Used when the original model is fragile and requires the use of non-durable moulding material.
Nylon Fibres – Added to Hypertufa add strength and cohesion.

Perlite – Volcanic glass superheated to form a lightweight aggregate which can be used in Hypertufa. Has a high moisture content.
Plasticizer – An ingredient that can be added to a Hypertufa mix to increase it’s workability.
Portland Cement – A powdery substance that is produced by burning a mixture of clay and limestone at a high temperature. It is a primary ingredient in Hypertufa.
Positive Mould – A concave mould which prevents the escape of the moulding material during the moulding process.

Rebar – Steel bars usually used in concrete to provide reinforcement. Can be used to make an armature in Hypertufa projects.

Sand Casting – The process of manipulating sand to create a mould and then filling the mould with Hypertufa.
Silicon Dioxide – Can be added to a Hypertufa mix to increase density and water resistance via a chemical reaction.
Slurry – A paste made with Portland cement and water.
Set – The initial hardening of Hypertufa before it has fully cured.

Tufa – Naturally occurring soft or porous rock formed by water deposits. Hypertufa is an artificial version of Tufa.

To get more information on different Hypertufa projects I recommend The Hypertufa How To Manual by Claudia Brownlie.

Posted in Hypertufa Information | No Comments »

Hypertufa Trough

March 4th, 2008 by Seb Brown

In this post I will explain in a step by step process how you can build a beautiful and practical hypertufa trough for your garden or patio. Hypertufa troughs are very plant friendly containers to use. This is due to there think porous walls which act as a reservoir between watering and allow air to flow around the roots. Hypertufa troughs also have a very natural appearance in the garden as they attract mosses and lichen.

To make a mould for our hypertufa trough we are going to use two cardboard cartons, one smaller than the other to fit inside it. There needs to be a 5-6cm gap around all the edges so that the walls of the trough will be thick enough. For larger hypertufa troughs obviously you will need to increase the wall thickness.

Place the large cardboard carton on a piece of plastic sheet on flat ground. Place concrete blocks or other similar heavy items around the edge of the carton. This will stop the edges bowing out when the hypertufa mixture is added and the carton becomes damp.

You now need to mix up some hypertufa. This is done most easily with a wheelbarrow and a shovel. We’ll be using the strong hypertufa recipe discussed in a previous post. Measure out 3 gallons of sifted peat moss, 3 gallons of Perlite, 2 gallons of Portland cement and a handful of loosely packed reinforcing fibres into the wheelbarrow and mix thoroughly with the shovel. If you want to mix the ingredients by hand that’s fine, but wear some tough rubber gloves.

You now want to add the water very gradually, so as not to make the mixture sloppy. You should be able to grab a handful of the mixture into a ball and it should hold together. The amount of water needed will depend on the dryness of the peat moss.

Take the hypertufa mixture and fill the large carton to a depth of 5-6cm. Push small pieces of dowel or bamboo through the mixture to create drainage holes, these will be removed later. Make sure the mixture is compacted by using the end of a piece of timber to tap it down, especially in the corners and around the drainage holes.

Now place the smaller carton inside the larger one, making sure the gap is even around all the edges. Place a small amount of sand in the smaller carton to stop it from floating up and to support the sides. You will need to gradually fill up the inner carton with sand as you build up the walls of the hypertufa trough.

Build up the walls of the hypertufa trough gradually, making sure to compact the mixture as you go with the end of the timber. When the walls are at the desired height leave the trough for 24 hours.

When you come back to your hypertufa trough the next day, you should carefully remove the sand from the inner carton and the wet cardboard from the sides, inside and out. Don’t worry about the bottom at this stage and don’t try to move it as you’ll lose your hypertufa trough.

Take a wire brush a rough up the sides and edges to give your hypertufa trough a more natural look. You can also score designs into the sides at this stage but be careful not to damage the trough as it will be quite fragile.

Now leave for a further week to cure and there you have it, a hypertufa trough for you garden or patio.

To get more information on different Hypertufa projects I recommend The Hypertufa How To Manual by Claudia Brownlie.

Posted in Hypertufa Trough | No Comments »

Strong Hypertufa Recipe

March 4th, 2008 by Seb Brown

This recipe is stronger than the basic hypertufa recipe I wrote about previously. It is good for making hypertufa troughs as they need to be made quite strong. The ingredients are:

  • 2 Parts Portland Cement
  • 3 Parts Sifted Peat Moss
  • 3 Parts Perlite
  • Synthetic Concrete Reinforcing Fibres (about a hand full for a hypertufa trough)
  • Water

Just a just a quick note to remind you that Portland cement is NOT concrete. Portland cement is an ingredient of concrete. Be sure to pick up the correct sack, they are heavy!

You should be able to get most of the ingredients in your local hardware store. The reinforcing fibres might be a little more tricky to get hold of but they should be available in your local masonry supply store.

Mix your ingredients well in a wheelbarrow before you add the water. When you add the water, do it slowly so you don’t make the mixture sloppy. You should be able to grab a handful of the mixture and mould it into a ball and it should hold together. The amount of water you need to add will depend on how dry the peat moss is to begin with.

To get more information on different Hypertufa recipes for different applications I recommend The Hypertufa How To Manual by Claudia Brownlie.

Posted in Hypertufa Recipe | 1 Comment »

Hypertufa Video

February 18th, 2008 by Seb Brown

Here is a quick video showing you how to create a Hypertufa trough. They use the same basic Hypertufa Recipe I posted previously.

For more information on creating Hypertufa troughs and other objects I highly recommend the The Hypertufa How To Manual by Claudia Brownlie.

Posted in Hypertufa Video | No Comments »

Hypertufa Recipe

February 12th, 2008 by Seb Brown

There are quite a number of varying Hypertufa recipes you can make. The particular Hypertufa recipe you use will depend on what result you are trying to achieve. A basic Hypertufa recipe will generally contain varying amounts of peat, Portland cement, perlite or vermiculite, sand and water. The following is a good basic Hypertufa recipe:

  • 1 part pre-mixed Portland cement/sand mix
  • 1 part peat
  • 1 part perlite or vermiculite
  • water (amount will vary depending on how dry the peat is)

You can vary the Hypertufa recipe depending on how heavy/strong you want your creation to be or if you want to carve it. You can also add cement colorants to the mix to give a more realistic rock color.

To get more comprehensive information on different Hypertufa recipes for different applications I recommend The Hypertufa How To Manual by Claudia Brownlie.

Posted in Hypertufa Recipe | No Comments »

What is Hypertufa?

February 9th, 2008 by Seb Brown

So what is Hypertufa?

Well, Hypertufa is an artificial stone used for making, amongst other things, garden ornaments, pots and troughs. It is made from various aggregates and bonded together with Portland cement. It’s used as a alternative to natural tufa, which is a slowly precipitated limestone rock.

A Hypertufa pot is very porous which makes it good for plant growth. It is also fairly light in comparison to other pots made from terra cotta or concrete and can cope with low temperatures down to -30C.

I hope that gives you a quick overview of Hypertufa. You can find further information about Hypertufa on this site. Also I highly recommend The Hypertufa How To Manual by Claudia F. Brownlie.

Posted in Hypertufa Information | No Comments »