InfoI want to get into this so I’m going to use this area of my blog to assemble all the bits and pieces. I have a vacuum chamber which I have used a bit – and a pressure pot which I have not. To start with, take a look at the following video which is a basic overview of the difference between the two. |
Vacuum versus PressureA look at using a Vacuum Chamber vrs a Pressure Pot. In this case the guy is using the Pressure Pot for his woodworking. On the International Association of Penturners forum I found this: Vacuum makes the bubbles larger, so that they will float up to surface and pop. If the bubbles originate on the edge of an embedded object, they will have a greater chance of dislodging. After degassing, the resin is returned to atmospheric pressure before it gels. Pressure makes the bubbles smaller, so that they will be invisibly small in the hardened resin. It must be applied from the time the resin gels (or before) until it solidifies. Either or both can be used, as the processes compliment each other. I’ve used both on some of my Polyester Resin (PR) and Alumilite Clear casts. Vacuum alone works well on low viscosity resin such as straight Silmar 41 (provided you pour before it gels). Some people have also had success thinning PR (with heat or with styrene) without vacuum. Viscous resins such as Alumilite Clear or thickened PR require pressure — vacuum alone is not sufficient. I also use pressure on Alumilite White and Alumilite Black. |
Peter Brown covers the difference between a pressure pot and vacuum chamber with a test run with resin for each. |
SumerisingAn article by EnvironMolds Artmolds titled “When to Use Pressure Pot and Vacuum Chamber” effectively summarizes for us (linked). |
My Vacuum Chamber
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![]() I also noticed that the center ID ring is quite crudely finished (like .. not). I need to take a Dremel to that. |
My Old Vacuum Pump
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Converting a Harbor Freight Pressure Pot for Resin CastingJake Thompson shows us how to convert a Harbor Freight pressure pot to use it for resin casting The Harbor Freight 2-1/2 gal. Air Pressure Paint Tank is rated at 60 psi maximum pressure. Working pressure is 30-60 psi. I would try to see how it works at 40 psi – no more than 50 psi. The import thing here is the pressure relief valve. The one that comes with the tank is adjustable but I would keep an eye out for a replacement from a name brand. Safety and all that. |