I use a variety of resins for my casting works. Most of my resins have a propensity to trap air and I regularly place the mold with the resin in a pressure pot. This removes all the air from the material and makes it disappear. As I let the cast cure in the pot itself, I get a perfectly bubble-free casting.



However, when I moved to making rubber casts, the bubbles seemed to return once I removed the rubber from the pressure pot. After several failed attempts, I gave up and bought a vacuum pump with vacuum chamber from artmolds.com.











Actually I had called up my regular supplier at EnvironMolds, LLC to discuss the issue first. He told me that a pressure pot does not work as effectively for soft casting materials like rubbers, especially silicones.



The suggested



Simply switching on the machine initiates the vacuum process that removes all the air from the rubber. All it takes is a few minutes and the air is eliminated, never to return. I leave the container in the chamber for some time and later open the plate slowly to allow a gradual introduction of air. Actually I had called up my regular supplier atto discuss the issue first. He told me that a pressure pot does not work as effectively for soft casting materials like rubbers, especially silicones.The suggested vacuum pump with vacuum chamber was reasonably priced and very easy to operate too. All I had to do was mix the rubber and pour it into a large container. The container should be big enough to accommodate four times the amount of rubber I wish to vacuum, as the rubber expands under a vacuum.Simply switching on the machine initiates the vacuum process that removes all the air from the rubber. All it takes is a few minutes and the air is eliminated, never to return. I leave the container in the chamber for some time and later open the plate slowly to allow a gradual introduction of air.











