Drawings and Sculptures
by
Olivier Duhamel
BRONZES - Step by step making of
Tiptoes
( Suivez la fabrication de Tiptoes.)
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Overview - Presentation |
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First I have to
make a wax sculpture. Many people prefer to work with clay, I
love working wax. It can be carved, modeled, painted on, melted out
etc... |
Je dois
tout d'abord faire une sculpture en cire. On peut également la
faire en argile mais j'aime travailler la cire, on peut la tailler, la
modeler, l'appliquer au pinceau, la faire fondre etc... |
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August 20
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20 Août Pour cette sculpture, j'ai tout d'abord modifié cette horrible cire…
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... to make this graceful
figure. I took me about 8 hours to give her a pose I liked and a rough finish. |
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... pour faire cette forme gracieuse. Elle fait à peu près 20cm de haut. Il m'a fallut à peu près 8 heures de travail pour obtenir une pose qui me plaise et lui donner une finition assez rugueuse.
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A view of my wax modeling
workbench. |
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Une vue de ma table à modeler la cire. |
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Next I want to make a mold. This because my wax will be lost during the casting process and if I want to make more castings in the future, I will need to remake the wax model. For this model I will paint a thin skin of flexible silicon around the entire sculpture and then build two half shells of plaster of Paris for a rigid backing. |
Je dois ensuite faire un moule.
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August 30 After having attached the wax to an old frying pan, I apply the first coat of silicon rubber with a paint brush.
I am using a silicon called Trade 26 which I buy from Topmark products |
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30 Août Après avoir attaché la cire dans le fond d'une vieille poêle à frire, J'applique la première couche de silicone au pinceau.
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Silicon rubber are two parts products. The recommended mix ratio must be observed
exactely and for small volumes, the use of a jeweler scale is recommended. The two parts must be mixed together thoroughly. My sculpture is small (20cm) and I use only 100g of silicon for each coat. The picture shows the tools I will need. |
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Les silicones sont des produits qui nécessitent l'ajout d’un catalyseur. Les quantités doivent être respectées exactement et l'utilisation d'une balance d'horloger est fortement conseillée. Le catalyseur doit être mélangé soigneusement. La photo montre les outils dont j'aurais besoin. |
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August 30 This is how she looks after the fourth and last coats. All undercuts have been filled in so that the mold can easily be removed from the plaster shell that I will next build around her.
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30 Août La voici après la quatrième et dernière couche. Tout les creux et escarpements on été remplis pour que le moule puisse sortir aisément de la coquille de plâtre qui viendra ensuite enfermer le silicone.
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August 30 I clean the runoff with a sharp knife. I have only used 400g of silicon (20 dollars), used 4 plastic cups, one paintbrush, two pairs of rubber gloves and spend 2 hours. |
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30 Août Je découpe les bavures de silicone. |
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September 6, 2006 I now need to build two half shells of Plaster of Paris around the silicon. My local hardware store ran out of Plaster of Paris. Tired of waiting, I bought a bag of something called "Casting Plaster". Let us see if this works... |
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| To separate the two shells I need to build a wall along the figure parting line. I like using water clay to build that wall. I flatten some clay on a wet board to a thickness of about one centimeters and cut bands about 4 cm wide. |
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| next I stick these bands along the parting line of the structure... |
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| The clay does not always stick to the silicon and also because the clay may sag under its own weight, I attach reinforcing lump of clay at the back of the wall. |
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| When all done, I make some "keys" around the wall. These are small holes in the clay that will help the two half shells to join properly when the mold is finished. |
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| This is not really necessary but I like to paint some Vaseline against the clay wall. This helps removing the clay from the plaster when the first half shell has set. |
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| I am now ready to mix the plaster with water. here, I estimate that will need one kilo of plaster. If that is not enough I can always mix some more. Follow your supplier mix ratio. Remember to measure plaster by weight, not volume. |
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| Apply the wet plaster by hand. |
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| When done, I smooth the plaster surface with a wet cloth. Not really necessary but looks cleaner... |
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... and I also trim the edges with a knife. |
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The plaster will be hard in about an hour. At that point you can make
the second shell. In this case dinner is ready, we are having a
cabbage soup and an apple pie) and I decide to call it a day. I cover
everything with a wet cloth so the clay will not dry and will be
easier to remove when I am ready to continue.
I have spend one hour, two pairs of rubber gloves and about 0.70 dollars of plaster.
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September 7 When the plaster is hard (about two hours), remove the clay from the back and clean everything. Make the second half
as you did the first but this time it is very important to apply a
good release agent on the dry plaster. |
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| A nice mould drying. Notice that there is quite a mess around my frying pan. It would have been a good idea to work on old newspaper. |
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September 8.
Let cure overnight before opening the mould. Gently pry the two shells apart with a knife |
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| Et voila ! We now need to cut the silicon to remove the wax trapped inside. |
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| Using a sharp knife I cut starting from the base and open the silicon as I go to see what I am doing. |
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Only cut enough of the silicon to get the wax out. No need to cut
everything.
Be very careful. If you mess this up and damage the mould you would have wasted a lot of time and material and will need to start over again from the beginning. Silicon cannot be fixed, patched, glued etc.. My mould is ready for use. It is recommended to let the silicon cure 24 hours or more before pouring hot wax in it but in this case I made the silicon skin 2 days ago. before I do that I spend half an hour cleaning the workshop, melting and cleaning the wax, putting the clay away in a wet towel for storage until next time. for this second half of the shell I have spend one pair of rubber glove, a few cents of vaseline, a perhaps a dollar of plaster. |
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In summary it took 4 hours an a half of my time and about 25 dollars of material to complete this mould. I find this moldmaking technique to be the easiest, fastest and most cost effective way to make a small to medium sized mould. The advantage of cutting the silicon with a knife is that you get a very clean seam line and only where it is absolutely needed. The advantage of starting with a thin layer of silicon is that you are almost certain not to have any bubble in your mould. Now I will cast a duplicate wax in my new mould. To be continued |
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Contact |
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© Copyright Olivier Duhamel 2003-2009