I am often asked if a vacuum chamber or a pressure pot is required in the fine fine art of mold making and casting. As with so many answers in life, a "yes" or "no" answer is not possible without first learning more information about the project. Except for water clear resin, where tiny air bubbles will obscure the clarity of a piece, and so on equipment is a must, my answer most often is, "It will depend. " That is bad, I am aware. So the purpose of this article is to provide the specific answer you are looking for.
For informal mold making and spreading, you can pour your materials in a high, narrow stream as one nook of your mold container to reduce the inescapable air bubbles. This allows air to escape as it travels down the narrow stream as you are pouring. Vibrating the mold, or mold box helps, as well, either mechanically, by knocking on it with your knuckles, or by inserting a vibration source against the mold box, like a hand sander. These types of are all great facilities tricks that will definitely reduce air bubbles. Nevertheless they do not eliminate them entirely. When that is your goal, keep reading00.
So if you are planning to create conforms and castings on a regular basis then you should bite the bullet and acquire the right type of equipment to achieve professional results. Just as one can do cabinetry using manual operating tools such as a hand saw, better and faster results are often obtained through the electric saw or slice saw. The proper tools, for the right purpose, go a long way in obtaining steady acceptable results in any industry or hobby for that matter.
"What are the differences between the two and do I need both" are the essential questions I most often receive. As the brands imply one chamber that is provides air pressure while the other removes air pressure. Yet only one actually removes air from your mildew making and casting substance - the vacuum step, while the other simply hides it--the pressure pot.
Stress chamber works by providing up to 50-psi of atmospheric pressure. If you remember your high school science, normal sea level pressure is about 14. 7- psi. Thus, the larger pressure works to compress any air pockets in your material and squeezes them down to almost microscopic size - thus making them seem to be to disappear. The air remains though, but you just can't start to see the bubbles now. But, once you release the air pressure back to 14. 7-psi, the environment bubbles will return - that is unless air is contained as it would be if the substance you were pressurizing solidified to a solid, like a hard resin, gypsum plastsorter or epoxy. If your material was a mildew rubber though, such as silicone or polyurethane, the flexible rubber will not contain the compressed air bubbles and they would expand within the rubber normal again size, even though your rubber has cured.
Thus, the pressure pot is best suited when your mold making or throwing material cures to a great and the vacuum step can be used to remove air from flexible rubbers. Typically the vacuum chamber can also de-air solid resins and epoxies, too. But since it takes a little more time to create a vacuum, and certain resins are fast-cured, the pressure chamber is the tool of choice in those instances as it can be quickly pressurized, faster than a vacuum step can be evacuated.