A vacuum chamber and a pressure pot are both used to degas, or remove air bubbles. The difference is in how they work, and how and when to use them when you're casting epoxy.

Here are some simple ways to think of the differences between a vacuum chamber and a pressure pot.

When to use a vacuum chamber in your epoxy castings

• Removes air pressure in order to remove air bubbles
• Can be used to degas individual resin and hardener components in the mixing cups, after they're dispensed at the proper mix ratio, but before they're mixed together, then poured into prepared molds
• Can be used to remove air bubbles from an epoxy casting that has already been poured into a prepared mold
• Can be used to stabilize porous wood with epoxy before embedding the wood in a casting
• HOW TO USE A VACUUM CHAMBER: Place the filled mold in the vacuum chamber and use a very high vacuum pressure setting to force any air bubbles to rise to the surface of the liquid epoxy, where they'll pop. The higher the vacuum pressure, the more effective the degassing will be. Restore normal pressure once all the bubbles have been removed.
• NOTE: A vacuum chamber is not used to cure epoxy castings, it's only used to degas.

When to use a pressure pot in your epoxy castings

• Adds air pressure to compress any air bubbles until they're too small to see
• Can be used to remove bubbles from mixed epoxy that's been poured into a mold
• Can be used to cure an epoxy casting
• HOW TO USE A PRESSURE POT: Place the filled mold in the pressure pot, secure the lid, and set the pressure to 50 psi. The epoxy casting should remain under pressure until the piece has cured to a firm, hard material. IMPORTANT: Do not exceed the maximum PSI rating of the pressure pot you're using.
• NOTE: If there are any air bubbles in the casting mold itself, these can be compressed when pressure is applied, distorting the mold. Before casting epoxy in your molds, check to be sure that the resin molds are in good condition.