Vacuum Pumps – Single Stage vs 2 Stage Pumps

Hey there!

Today, let’s dive into the exciting world of vacuum pumps and explore the differences between single stage and two stage pumps. As passionate silicone toy makers, it’s crucial for us to know which type of pump suits our needs. So, let’s get started!

A Table That Doesn’t Tell You Everything!

	Single Stage	Two Stage
Speed	Slower	Faster
Vacuum Depth	Shallower	Deeper

How fast can you get to your chosen vacuum level?

Now, the speed of reaching your desired vacuum level may be more dependent on the cubic feet per minute (CFM) of the pump than it being a single or two stage pump. However, two stage pumps generally move air more efficiently. When you’re closely observing the vacuum gauge, you’ll notice that a two stage pump will make the needle move faster and for a longer duration.

If we compare a single stage pump with a two stage pump, the single stage pump may start to slow down when pulling the vacuum at around -15″ Hg (inches of mercury), whereas the two stage pump will typically continue pulling until approximately -20″ Hg. This means that a two stage pump will get you to your desired vacuum level faster. How cool is that?

How deep of a vacuum can be pulled?

To understand this, we need to talk about an often overlooked vacuum pump specification: the micron rating. While we usually measure vacuum in inches of mercury (which is perfectly fine for us), there’s another unit called microns. Microns measure the closeness to a perfect vacuum. At sea level, we have 760,000 microns, and as you get closer to zero, you’re getting closer to an ideal vacuum (the holy grail of vacuums, if you will).

Now, let’s take a look at the micron ratings for the Robinair 3CFM pumps. The single stage pump can ‘only’ go down to 80 microns, while the two stage pump can go down to an impressive 35 microns. So, even with the same CFM rating, the two stage pump can pull out more air.

Just a quick reminder, inches of mercury is absolutely fine for our purposes. But understanding the differences between single stage and two stage pumps means taking a peek at the micron ratings as well.

So, which do you need?

In my opinion, a single stage vacuum pump is perfectly suitable for making adult silicone toys. I usually recommend starting with a single stage pump, as it gets the job done. However, if you’re working on other projects besides silicone, then a two stage pump might be more versatile for different circumstances.

If you’re interested, I’ve put together a list of recommended vacuum pumps for making sex toys here. Check it out and find the one that suits you best!

Alrighty, folks! That wraps up our discussion on single stage and two stage vacuum pumps. I hope you found this both knowledge-packed and entertaining!

Catch you next time!

Derek