Tuesday 10 April 2018

Vacuum cleaner Chambers Versus Pressure Pots in Mold Making


I will be often asked if a vacuum chamber or a pressure pot is required in the fine artwork 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 part, and such equipment is a must, my answer most often is, "It all depends. " That is bad, I understand. So the goal of this article is to provide the specific answer you are interested in.

For informal mold making and spreading, you can pour your materials in a high, narrow stream as one nook of your mold package to reduce the inevitable air bubbles. This allows air to escape as it travels down the narrow stream when you are pouring. Vibrating the mold, or mold box helps, as well, either mechanically, by knocking on it with your knuckles, or by putting a vibration source against the mold container, for instance a hand sander. These kinds of are all great facilities tricks that will definitely reduce air bubbles. But they do not eliminate them entirely. When that is your goal, keep reading00.

So if you are planning to create molds and castings on a regular basis then you should bite the bullet and acquire the right type of equipment to achieve that is professional results. Just as one can do carpentry using manual operating tools like a hand saw, better and faster results are often obtained through the electric saw or cut saw. The proper tools, for the right purpose, go a long way in obtaining regular acceptable results in any industry or hobby for that matter.
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"What are the differences between the two and do I want both" are the essential questions I most often receive. As the titles imply one chamber provides air pressure as the other removes air pressure. But only one actually removes air from your form making and casting substance - the vacuum holding chamber, while the other simply hides it--the pressure weed.

The pressure 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 higher pressure works to compress any air bubbles in your material and squeezes them down to almost microscopic size - thus making them appear to disappear. The air is still there though, but you just can't see the bubbles now. But, once you release the air pressure back to 14. 7-psi, the air bubbles will come back - that is unless the air is contained as it would be if the materials you were pressurizing solidified to a solid, for instance a hard resin, gypsum plastsorter or epoxy. If your material was a mold rubber though, such as silicone or polyurethane, the flexible rubber will not contain the compressed air bubbles and they would expand within the plastic back to normal size, even though your rubber has cured.

Thus, the pressure container is best suited when your mold making or casting material cures to a great and the vacuum chamber can be used to remove air from flexible rubbers. The vacuum chamber can also de-air solid resins and epoxies, too. But since it takes a lttle bit 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 holding chamber can be evacuated.

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