Construction How-Tos For Carving & Scuplting in ‘Tufa
This article offers guidelines and a recipe for creating long-lasting hypertufa sculptures
In most cases, when one talks of hypertufa sculptures they mean tall upright objects. But that being said, you can use these guidelines for smaller objects, such as a small “garden face” you sculpt into a ‘tufa rock’s surface.
As with all hypertufa projects, I will repeat myself once again and say “practice makes perfect” when it comes to your desired outcome. Whether it’s the consistency of your recipe’s ingredients, or the final appearance of your sculpting, carving and/or texturing of the object, please understand that sometimes your first project may be a big, yet necessary “learning curve”.
This isn’t rocket science, but being familiar with the “basics” comes with practice.
Here is a recipe that will give you a durable, carvable and long lasting hypertufa sculpture. Your aim is to apply this first recipe in thin layers over your armature, building it up to the desired thickness. Then, you will use the 2nd recipe to add one or more layers thick enough to allow you to sculpt to your desired depth.
Recipe for application over the armature and to build up thickness desired:
1 part Portland cement
1½ parts peat moss
1½ parts coarse sand
Handful of poly fibers
Handful of silica fume
Recipe for the Final Layer(s)
1 part Portland cement
1 part peat moss
1 part coarse sand
Elmer’s Carpenter’s Exterior Wood Glue (or other bonding agent)
Sculpting and Carving
As mentioned above, once you’ve gotten the hypertufa sculpture’s walls almost as thick as desired, you will apply the final coats of the 2nd recipe. You will apply these last coats thick enough to allow the desired depth of your sculpting (or carving). Once the final layers have set up a bit, start your sculpting. Don’t let it set up too long or it’ll be too hard to properly sculpt.
You may wish to finish off the semi-cured surface with a stiff wire brush to get the surface smoothed out (if that is part of the final look you are trying to achieve.)
These are good basic directions for a successful hypertufa sculpture project. If you are brand new to working with hypertufa, then I whole-heartedly suggest you refer to my other articles to familiarize yourself with important facts before you attempt this project.
About Bonding Agents and Glue
What Is A Bonding Agent? How Much Should Be Used In Your Recipe?
A bonding agent is an additive used in a hypertufa recipe to cause a “new” layer to adhere to an “old” layer. In other words, you are able to apply layer upon layer of ‘tufa and everything will stick together. Now, this is a good thing! :-)
Bonding agents are located in the cement products isle at Home Depot or Lowes, for example. A bonding agent is similar to Elmer’s Wood Glue, thusly many crafters use Elmer’s Wood Glue with great success (and save a little money, too).
The amount to use is not set in cement (not to make a pun) but in general for every 10 cups of dry mix ADD approximately ¼-cup of bonding agent. I suggest you add it into the water that you’ll use to moisten your dry mix.
NOTE: I’ll mention that rumor has it that the maestros “Little and Lewis” use Elmer’s Carpenter’s Wood Glue as their bonding agent. I’m just passin’ along some interesting info here, gang!
Armature: A Strong Inner Frame
The Sculpture Must have a Very Sturdy Inner Frame Construction
You’ve got to use something very sturdy on which to build hypertufa sculptures. But, almost anything can be utilized: PVC pipes, wooden structures, metal rods or rebar. Styrofoam can be used successfully, also. Build your armature by nailing, gluing or welding it into the ‘shape’ you want.
You will then use hardware mesh (also referred to as hardware cloth) to cover the armature. This will serve as your form on which to apply the hypertufa layers. Wrap it and wire it to your form if needed. Make sure the hardware mesh is secured as tightly as possible to the armature.
Due to the complexities involved with building an armature, there is no way in this particular article that I can address all the how-tos. Your ingenuity and creativity will certainly come into play in this particular step of your sculpture project. Let common sense dictate the particular requirements that your inner frame will need.
May there be many hypertufa sculptures gracing your garden in years to come! :-)