One of the primary problems facing many small scale mould makers is air bubbles inside their silicone mould. The bubbles inside the silicone rubber mould itself are generally not really a serious issue. The catch is if the air bubbles form at the casting surface making the mould unusable.
There are several ways to use to make sure bubble free silicone moulds:
1) Special pouring techniques
2) Applying compressed air
3) Using Vacuum to take out bubbles
4) Using pressure to force air into solution
The surface where casting materials meet silicone moulds is a vital part. It can be therefore necessary that special care is given to make certain no bubbles form when pouring the silicone rubber into the mould box and to the model. It is crucial never to simply pour the rubber over the top of the model in one go. Begin by pouring a modest amount of rubber in to the mould box and initiate tilting it in several angles to produce the rubber slide overall surfaces. This wets the top of the model having a fine film of rubber and then any air bubbles can be simply seen and popped by using a pin or paint brush.
Also you can work with a paint brush to use this first fine film of rubber on the top of the model. Select the method which works the best for your chocolate silicone mold.
When you are satisfied that the bubbles have been popped you may pour all of those other mould making rubber into the mould box. Pour from as high a point as possible in a fine stream in order that any bubbles inside the mixture will pop around the way down. Aim this stream into the corner of the mould box instead of along with the model.
If you have usage of an aura compressor you have an efficient way of popping air bubbles. Ensure you have about 30psi pressure as well as a small nozzle tip and after pouring the first little bit of rubber to the mould box blow the material over the model to wet the outer lining in the similar way to the first method. The initial film of rubber must be bubble free.
Bubbles are usually a direct result air beaten to the rubber through the mixing process. Ensure you stir the mix in the steady and slow action. There is still air within the mixture however and this could be removed through the help of a vacuum chamber.
These vacuum chambers make use of a vacuum to suck out any air bubbles from the mixture and convey them to the top where they are often easily removed. Each vacuum chamber has their particular 41dexfpky regarding how to apply it but this is a guide:
1) Use an oversized container for mixing. Allow for the mixture to double in proportion when placed into the chamber.
2) Mix both part A and part B within the container and place to the chamber. Close the chamber and start the vacuum pump.
3) The mixture will start rising to the top level of your container. Every one of the air bubbles inside the mixture will rise on the surface. Because the mixture approaches the top of the container release the valve which breaks the vacuum and the mixture will drop to the bottom as well as the air bubbles will pop. Do this two to three times to make certain all bubbles are removed.
4) Release the vacuum the last efforts and consider the mixture out of your chamber. It is actually now ready for pouring.
The use of a vacuum chamber is often only easy for cake rolling pin which have a fair amount of time setting. A few of the quicker setting silicone rubbers sets too rapidly so you won’t hold the a chance to vacuum the bubbles out. Make sure you look into the label about the product you will be using.