Tip Time: Under Pressure

This post is mainly for beginners.

I am going to clear up some misconceptions about working with a vacuum chamber and a pressure pot...

It only makes sense that putting resin in a vacuum chamber while it cures will suck all the air bubbles out...


A vacuum chamber is strictly for degassing silicone. You never put your resin in the vacuum chamber. I've seen a lot of people make this expensive mistake.

You would think that pressurizing your resin would push the resin though out your mold getting a perfect pull every time.

Wrong again.

You need to vent your piece adequately. Fingers (for example) are usually problem areas. You need to glue toothpicks or bamboo skewers to each finger on your piece before you cast. Otherwise, you will still get air bubbles in them no matter how much pressure you put in the tank.

Resin is a thermosetting plastic which means that it heats up as it cures. The heat creates bubbles (they look like little soda bubbles).

Quick set resin heats up hotter and quicker, creating more bubbles.

When you use a pressure pot it shrinks those bubbles.

Thats it.

It actually doesn't eliminate them either. But it does shrink them to a microscopic level. They even exist in a crystal clear piece.

Hope that helps.

Thanks for reading.

Your Friend,

-Scott Cherry

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