How to make and work with cellulose cement
Method:
1. Armature: The first thing to do is to build an armature of the object you want to make. An armature can be built out of just about anything but it must be rigid as the cured material can crack if the armature flexes especially where the layers of material are thin. Thicker material weighs more but is structurally quiet strong so decisions have to be made at the outset about strength vs weight. This medium can be readily be spread over a foam core as well as steel wire mesh on a steel frame for larger, more open works. However this material used far less bird wire mesh (two layers is usually enough) than would ferro-cement where at least 5 layers of mesh are required to prevent the render/plaster from slumping through. although I tend to use mild steel reinforcing as my base frame. Wood is just as good. See below for an armature on a steel frame
2. Preparation. Once the armature is ready then the next step is to produce the material. Taking ordinary newspaper (glossy paper, cardboard, egg boxes etc are not at all suitable so do not use them) shred these into half to three quarter inch strips (12mm to 18 mm) strips. Place these into a bucket, or mixing container (I use 20 litre - 5 gallon- paint buckets made out of metal or hard plastic). When it is about a third full add water to cover the paper. The amount of water to paper is critical. Too much water and the paper stays in lumps and akes a long time to break down. Taking an electric drill with a paint stirrer ( as per the illustration) tightly fixed in the drill chuck, mix up the paper until it is a fine slurry. I have noted over the years when the mix when the grey mixture starts taking on a lighter brownish hue then the slurry is properly mixed. Now it is time to drain the water out of the slurry. I use a piece of old hessian for this and pour the mix into that and lightly press out the excess water. I then store this material in a plastic container which has a sealed lid. Before sealing I add some bleach and thoroughly mix that into the moist mix to prevent it from getting mouldy while it is stored. The moist mix can be stored for months this way.
3 The mix. When I am ready to lay the material onto the armature I mix up as much as I will be able to use on in about a half an hour as after that the mixtures starts goiung. Once its starts going off it can still be used but if there is any material left over it must be discarded. DO NOT put this mixed material back into the storage bin. One can vary the mix a bit making it a bit stronger or weaker as the situation warrants but the mix I have found the most versatile is:
- Equal parts of the paper and cement by volume.
4. Method: First I thoroughly mix in about 10% to 15% of a cement conditioner/ plasticiser (Bondcrete) to the paper. Then I add in the cement and mix it thoroughly. It should be about the consistency of clay but the mix can be varied according to what it is being used for. Shrinkage is not a great issue with this material but the dryer the mix the less the shrinkage. I prefer to use off-white or ivory cement as it gives a better range of options for the finish but ordinary grey cement is just as good. It is really a personal preference.
5. Applying the material. The first layer of the material needs to be a very thin one, especially when it is applied over mesh. Too thick and the weight of the wet material will cause the material to slump off the armature. This is then left at least overnight to dry. Lightly wet the first layer with water from a spray bottle and apply the next coat. The second layer is used to rough out the final shape but I suggest that one resists trying to get too close to the final shape yet. All of my students have tried to work with this material as if it were clay. It is not and one should take that into consideration. I tend to leave of the detail until the very last layer. At any point the material can be ground off or shaped with an angle grinder using a ZEC disc or very course sanding disc. It can be drilled to add in other elements or as a support for any changed shape that you might decide to as you proceed with the work. It can be carved but grinding shapes into the surface gives a better result
6. Finishing. This material is very versatile. It can be finished to just about any surface a creative mind might want to come up with. What it needs however is to be sealed against the incursion of moisture. One can use normal house paint (interior or exterior PVA ) or a clear sealer like those used on concrete driveways, or a host of other surface treatments including covering it with a thin skin of fibreglass. any surface in contact with the ground should be sealed witha bitumen based sealer.
A wander though theh works shown under Cellulose Cement will give you some idea of what is possible. But these finishes are no limit on what a creative mind might be able to achieve with this material.
Here is how the above armaure turned out when the work was completed and left in its natural colour. It was sealed withseveral coats of a clear sealant
