“SILICAFUSION” is an innovative process for refractory moulding, combining the traditional plaster technique and the ceramic method known as “shell mould”.
This allows important savings in refractory material as well as in energy costs(fuel, gaz) and man-hours.
The following is a list our products' characteristics and advantages :
- Reduced costs : 1 ton of “SILICAFUSION” product replaces 5 tons of refractory plaster.
- 80% energy saving : kiln-firing requires only a few hours even for large pieces due to the thin
shell-mould and a hollow core.
- Important reduction in chasing time : less feeds and vents on the wax model / the remarkable surface on castings / vents are sometimes unnecessary as “SILICAFUSION” is a highly porous material.
- Ease of mould manipulation and optimization of the furnace space.
- Ease of knocking-out.
- Reductions in waste and waste disposal : possibility to recycle around 70% of waste after crushing and seiving.
- Low outlay costs to implement the “SILICAFUSION” process : low-cost tools and equipment.
- No continious stirring of the "SILITONITE" slurry.
- Number of slurry layers reduced by half, compared to standard shell-mould techniques.
“SILICAFUSION” is a patented process in France, and the result of many years of research with refractory materials. It is a breakthrough that simplifies and cuts outlay costs whilst reducing any negative impact on the environment (carbon emissions and chemical dispersion for example).
Bronze-casting is one of the oldest known metal-forming techniques. Used for over 3000 years for its accuracy in re-producing complex metal objects. It is used for sculptural art as well as the automobile, space and aeronautics precision industries. The main disadvantage is the overall cost as it can require specialized equipment, costly refractory products and binders, involves many mould-making operations and quite a lot of skilled labour. Another disadvantage is the waste produced by investment casting techniques: either large quantities of waste with plaster block-mould techniques or waste of higher toxicity with modern ceramic shell techniques (phosphoric acid to eliminate mould residues on the metal for example).
This is where “SILICAFUSION” makes the difference : it incorporates various products, including a new sand-based compound called “SILITONITE”. It produces a shell that combines the advantages of the two main investment casting techniques (the plaster block-mould technique and the ceramic technique) commonly used in industry and art workshops.
Cost : the sand-based “SILICAFUSION” relies on low-cost sources that are widely available and in abundant supply. “SILICAFUSION” products will remain inexpensive.
Quantities needed: with the “Silicafusion” process, the mould is strong enough to allow the implementation of a hollow core, requiring neither steel reinforcement nor a wire-mesh. This reduces the amount of materials needed to reproduce the piece.
Equipment needed : It is a foundry process that is adapted to manual application as well as mechanical techniques found in semi-industrial production.
Production time: the process is rapid and easy to implement in comparison with other techniques. High porosity reduces the need for vents and the nature of the surface coating permits swift removal. Furthermore, the clean accurate surface of the metal reduces the subsequent finishing.
Heating time: “SILICAFUSION” moulds are thinner and have better refractory properties (a tenth of the kiln time is required). This allows a significant reduction in energy consumption and in carbon emissions.
Waste : “SILICAFUSION” generates less waste than plaster techniques and the wastes are toxin free and 70% can be recycled. The process eliminates the use of colloidal silica, phosphoric acid, zircon and other compounds that cause health and safety problems in the workplace and the high disposal costs investment-casting foundries incurr.
Applications: “SILICAFUSION” can be used on all types of patterns and can support a wide range of non-ferric alloys (bronze, silver, brass, aluminum and various copper alloys). It suits any size of foundry production and can be used to produce small pieces of a few centimetres or heavy pieces of more than several metres in length. It meets the needs of precision industry and those of sculpture-casting and crafts.
The above explains why “SILICAFUSION” can represent major improvements for companies looking for ways to improve the ecological impact of their production processes.
Many on-site demonstrations have been made and have shown that the “SILICAFUSION” process is well accepted by industry and craftwork professionals who greatly appreciate its many advantages. The process is fully functional and safer than traditional techniques. There are no technical problems for its implementation in any type of foundry.
The “SILICAFUSION” process offers solutions to its potential customers. Its implementation would have a positive impact on their business. Energy consumption is cited by metal-casters as one of their most significant costs. VOC in binders and cores constitute one of the most documented risks to human health in the industry.
“SILICAFUSION” is safer and easier to use.
“SILICAFUSION” is a top quality material meeting the highest requirements of professionals involved in lost-wax casting.
Description of the product.
Three products are necessary for its implementation:
- R35 : a first-coat.
- Silitonite : a ceramic slurry.
All products except chamotte are produced in our own workshop, and are carefully packaged by us for transportation to our clients in France and abroad.
Implementation involves two operations:
Firstly, there is the attachment of runners and vents to the wax pattern and the application of the first-coat for a faithfull reproduction of the surface detail; this is the thixotropic R35 layer. Mixed with water it is applied either manually or with a spray-gun. Setting time is very rapid (a few minutes), especially when used with spray gun. Two layers will be required so that the wax is homogeneously covered.
The second operation requires the building-up a solid shell of successive layers with the “SILITONITE” and chamotte mixture. The purpose is to make a shell-investment retaining the mechanical strength of R35 whilst eliminating the need of block-mould reinforcement or a metal-cylinder mould as with the plaster block-mould investment technique.
To achieve this end the moulding is coated with a slurry of “SILITONITE”, either by dipping or spraying, each time followed with a dusting of chamotte. Having respected the drying time (a hot-air cabin at 35° greatly accelerates the process) the operation has to be repeated until a shell of 5 to 10 mm is obtained, and varies according to the dimensions and thickness of the wax-pattern.
The strength of the shell achieved with our slurry allows the number of layers to be halved in comparison to other ceramic-shell techniques. In addition, the “SILITONITE” slurry doesn't require constant stirring as it has a low elutriation.
A very attractive feature of the “SILICAFUSION” process is the option to create mouldings with a hollow-core, this is achieved with a slush-coating within the cavity and follows the same procedure as for the outside of the mould.
In many other foundry techniques all cores have to be solid.
The hollow-core helps to make substantial savings of raw materials and of energy for the kiln-firing, it also reduces significantly the weight of the mould.
Never-the-less, small solid-cores can be made with R35, these are anchored by support nails as with the standard process for a block-mould.
Dewaxing and firing
Once moulding is finished, the next steps are the dewaxing and firing.
Using “SILICAFUSION“ and a hollow-core, firing time is reduced to a tenth of that of plaster block-mould investment. In addition, as moulds are less bulky “SILICAFUSION” makes it possible to optimize the kiln space.
The length of the cycle ranges from 5 to 7 hours.
- Dewaxing at 150° takes from 2 to 3 hours.
- Firing at 750°, is attained in 3 hours and is then maintained for 1 to 2 hours in the case of a hollow-core, regardless of the overall size of the piece.
With a solid-core, the duration or the firing is calculated on the basis of the core's radius and will need to be longer.
Metal-casting and knocking-out.
At the end of firing, the casting can take place. Moulds are taken out from the oven and packed in dry sand, with the sprue-cup to the top ready to receive the molten metal. The R35 coating being very porous, generates very small amounts of gas during the pouring and is an additional guarantee of quality.
1 to 2 hours after the pouring, it is possible to knock-out the moulds using a mallet to break the refractory shell and free the casting. High pressure water will take off the last traces of coating on and reveal an exceptional cast-surface.
Easy and rapid knocking-out produces only a small amount of rubble of which about 70% can be recycled, after crushing and sieving, as chamotte in future moulds.
Equipment required for the implementation of “Silicafusion” process:
- hot-air cabin
- de-waxing kiln
- The gyroscope facilitates the handling of waxes when applying the refractory molding to pieces 40 cm and above.
- The ventilated hot-air cabin allows rapid drying of the “SILITONITE” layers and considerably increases the mechanical resistance of moulding.
- The viscometer is recommended to adjust the fluidity of the “SILITONITE”.
All items except the viscometer are available on the Internet, via the link proposed on our site.
The gyroscope and the hot-air cabin can be made in-house following the plans available on the “Equipment/Tool” page of the site; all these items can be made for a small cost.
A detailed worksheet is provided with the products for its implementation.
The training sessions are intended for sculptors, metal-founders, designers and anyone with a passion for moulding and metal-casting. They present, in detail, the different steps of the lost-wax casting process.
Several options are proposed, from silicon-rubber moulding through to the implementation of refractory “SILICAFUSION”, and culminating in the melting and the casting of bronze.
The equipment and products are included in the cost of the course, the bronze remains as an extra cost to the trainee. The trainee will have to provide work-clothes and protective-shoes.
The bronze-pourings are carried out by Marc Lebreton, founder and sculptor.
During training silicon-rubber mould, a study pattern in plaster, wood, metal, or wax brought-in by the trainee is used (patterns from 15 to 60 cm maximum).
For the “SILICAFUSION” and bronze-casting courses, the trainee must provide his/her own piece, these must be in wax, no core or other casting artefacts (runners, vents) should be attached.
All pieces produced by the trainee in the workshop remain his/her property at the end of the course.
Working with silicon-rubber and wax. Practice on gyroscope depending on the size of the piece.
Duration: 10 days
Cost: 1500 €
Firing and casting.
Presentation of the “SILICAFUSION” moulding process and its implementation.
Bronze-founding and knocking-out (comments, questions and answers on various themes)
Duration: 6 days
Cost: 1000 €
Combined programme of the full lost-wax casting process.
This course combines the work of the two previous courses.
Duration: 15 days
Cost: 2000 €
There at present no specific course for the work with patinas on bronze. However, this can
be discussed and demonstrated during the sessions.
The courses take place at the 'Atelier de Fonderie d’Art du Couserans' in the charming village of Arrien en Bethmale (09800), French Pyrenees.
Route du col de la core 09800 Arrien en Bethmale
Contacts: Marc Lebreton tel: +33(0)6 23 62 67 43 -
N° Siret 48245290100036 N° Intracommunautaire: FR84482452901