27 Mar 2018 11:02
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The surface where casting materials meet silicone moulds is the most crucial part. It is therefore essential that special care is given to ensure no bubbles form when pouring the silicone rubber to the mould box and onto the model. It is important not to simply pour the rubber over the top of the model in one go. Commence by pouring a little amount of rubber into the mould box and start tilting it in various perspectives to make the plastic slide over all surfaces. This wets the surface of the model with a fine film of rubber and any air bubbles can be easily seen and popped with a pin or fresh paint brush.
You can even use a paint brush to 3D silicone molds for cakes decorating this first fine motion picture of rubber to the surface of the model. Choose the method which works best for your silicone moulds.
Once you are satisfied that all the bubbles have already been popped you can fill the rest of the mould making rubber into the mould box. Fill from as high a point as possible in a fine stream so that any bubbles in the mixture will pop on the way down. Goal this stream in to the corner of the mould box and not on top of the model.
Textured surfaces in clay models can be carved by hand but this technique can take a long time and needs a lot of practice to get the desired effect. Using special silicone or plastic structure pads can make process a lot quicker and more realistic.
These parts have usually been produced by taking impressions of real life surfaces such as rock and include a lot of detail which is often transferred to the clay-based model by simply pushing the pad onto the soft clay surface.
Rolling pins are perfect for preparing even thickness slabs. The particular thickness of the slabs can be easily manipulated by the use of wood strips. If you wish to create a 2cm thick slab then find two 2cm wooden strips and lay them parallel to the other person so that the rolling pin can run along the top. Then place the clay-based over the middle of these two strips and keep rolling the pin over until the clay is pressed to the elevation of the strips.
If you wish to create new texture surfaces you can certainly make them yourself by carving or pressing a textured surface into some clay. You can then pour silicone over the textured clay to create a long term texture pad. Another easy way is to use the new silicon putty which once blended has the consistency of clay and can be pressed directly onto a textured surface. This will dry in around 12 minutes and will form a strong but adaptable texture pad.
Final Variations
Methylated spirits can be brushed onto the model surface to smoothen the finish. This will likely dissolve the oil based clay enough to be able to break down any small, rough imperfections in the surface.
Once you have completed the model spray it with an acrylic sealer in either dull or gloss depending on what type of surface you require. This clear coat will also help to avoid the clay from sticking to your mold making material.