Pressure Pot vs. Vacuum Chamber For Banishing Bubbles

When it comes to creating with resin, the right equipment can make all the difference. And you might be wondering if you need a pressure pot or vacuum chamber for resin casting.

Do you need them? And if so, which one is right for your project?

Each method has pros and cons, and the choice ultimately depends on your preference.

How do a pressure pot and vacuum chamber work?

Here’s the BIG thing to know:

Pressure pots push compressed air into a chamber.

As air fills the pot, the pressure builds. This pressure forces the air bubbles to become so teeny tiny small that you can’t see them with the naked eye.

Vacuum chambers remove air from a chamber.

As this happens, bubbles in the resin rise to the resin surface and pop.

The pros and cons of a pressure pot for resin casting

Pros to using a pressure pot:

It’s great for eliminating bubbles in clear resin. It’s perfect to use for projects like paperweights and resin dice.

This is especially important if you’re using a quick-curing resin. These resins start curing before a vacuum chamber has a chance to work on the busting the bubbles.

Cons to using a pressure pot for resin:

It requires a compressed air source, so you’ll have to buy an air compressor.

Your project must stay in the pressure pot for the entire curing time.

It can turn into an IED quickly as too much pressure causes the pot to rupture. If you DIY a pressure pot, PUH-LEASE, buy quality equipment. This is not the time to save a few bucks.

⚠️ IMPORTANT: When using a pressure pot, release the pressure slowly to avoid accidents.

The pros and cons of a vacuum chamber for resin casting

Pros to using a vacuum chamber:

It’s easier to set up and use. Should you get things wrong, things suck inward, not push outward. Meaning if you make a mistake, you’ll ruin your equipment but are less likely to hurt yourself.

You can open the chamber before your resin cures to remove your project.

Cons to using a vacuum chamber for resin:

You’ll need to buy a vacuum pump to suck out the air.

💡 Pro tip: Make sure to use a vacuum pump rated for your chamber’s size. You don’t need to recreate the surface of the moon, but you need to get out enough air to create a vacuum.

Bubbles don’t always pop. While vacuum chambers get bubbles to the surface, you’re relying on negative pressure to make them pop. That doesn’t always happen with thick-mixing resin. (especially silicone) That means you may end up with beer foam on the top of your resin instead of a perfectly smooth surface.

So should you use a pressure pot or vacuum chamber for resin casting?

Well, it depends. But here’s how I like to use them:

When I need to have a perfectly clear, bubble-free casting, I use a pressure pot.

If I’m pouring silicone to make molds and only need the surface next to the mold template to be bubble-free, I use a vacuum chamber.

💡 Pro tip: If you’re a thrifty artist (hey-ya, my people!), start with a vacuum chamber. You can always remove bubbles from mixed epoxy, and then pour it into your mold.

Maintenance and Safety Considerations

Always wear the appropriate safety gear, including gloves and eye protection.

Learn about regular maintenance for your setup. Inspect your equipment regularly for any signs of wear or damage so you can replace parts.

Follow the manufacturer’s instructions for cleaning and maintaining your equipment.

What else should you know about using a pressure pot or vacuum chamber for resin casting?

Neither of these methods does anything to speed up resin curing.

If you have bubbles in your resin mold, they’ll be affected by these processes. That means a pressure pot will push the resin into bubble spaces. And a vacuum chamber will remove bubbles stuck in a mold too.

Pressure pots and vacuum chambers can misshape silicone. Be sure you’re using a stiff silicone mold.

Now here’s the really cool thing about all this…

You don’t have to use a pressure pot or a vacuum chamber setup for resin casting. If you’re a casual user, or you only want to try crafting with epoxy a few times, you can easily slay resin bubbles with these ten tips.

Since you’re looking at investing $300+ to create either one of these setups, keep things simple. IMHO, these are investments for people making items to resell, where customers expect perfection.

Like the dice made by @greenleafgeek

Want to learn more about the resin basics?

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