Complete P2S Filtration Upgrade Guide for Early Bambu Lab P2S Owners

If you’re running a Bambu Lab P2S in a small home office or tight basement space, P2S filtration is no longer optional—it’s a must for safe, long-term 3D printing. I’ve been having an absolute blast printing everything from a giant PUBG helmet to a small commemorative statue of a local restaurant from my hometown. But with my P2S in a tiny room, I knew I had to build a real exhaust and filtration setup.
In this post, I’ll show you how I upgraded my early 2025 Bambu Lab P2S with official external filtration and adapted it to work with a Fnatr filter system—even before the official parts widely released in the US.

If you bought your Bambu Lab P2S in 2025, you have the original rear panel—the one WITHOUT the external filter port. Newer units now ship with an updated back plate that lets you simply peel off a sticker, 3D print the external mount, add the official fan kit, and run a proper external filter.

But for early adopters, that upgrade didn’t come pre-installed. To get proper P2S filtration, you need to replace the back panel entirely.

At the time I did this upgrade, the official kit still wasn’t available in the United States. So I went on Call3D shop on Aliexpress and found what appears to be the genuine Bambu Lab rear panel kit—and I’ll walk you through the full build.

Before jumping into the install, let’s break down the real-world ventilation solutions for P2S owners:

• Official external filter mount: Clean, factory-supported, requires the new back plate.
• 100 mm hose adapter: 3D print an adapter to route fumes out a window or dryer vent.
• Fnatr filtration system: A popular enclosure-based filter often used with the A1 & A1 Mini.

I’m in a basement, so I plan to do a full window vent setup later. For now, I focused on creating a hybrid P2S filtration system using the official Bambu exhaust + the Fnatr filter.
One problem: The Bambu Lab external filter uses a larger hose, and the Fnatr uses a smaller one. So I designed and printed a custom reducer to go from ~100 mm down to 75 mm, letting me connect everything cleanly.

The kit includes:

• Updated rear panel with the removable external filter sticker
• Fan assembly with small control board
• All required mounting screws

Comparing to my original back panel: There was simply nowhere to attach an external filter before.
You CAN 3D print an adapter for the old panel if you want, but I preferred the clean, factory look of the official rear plate for my P2S filtration setup.

Installation is straightforward if you follow Bambu Lab’s official guide. A few key tips:

1. The hex key included with your P2S works for all rear screws.
2. There are three different screw sizes—keep them separated.
3. When you remove the panel, take the chance to clean stray filament from the internal housing.

• Low speed: ~600 hours
• Medium speed: ~400 hours
• High speed: ~200 hours

One big concern with P2S filtration and external exhaust is cooling the chamber while printing high-temperature materials like ABS or ASA.
By default, Bambu Lab disables the external filter when printing high-temp filaments to avoid chamber heat loss. My logic: By moving the Fnatr filter further away from the printer and only extracting exhaust air—not just pulling directly from the chamber—I can maintain more stable temperatures while still removing fumes.
This setup gives me a great balance: safer air quality + consistent printing conditions.

To double down on safety, I also replaced the stock internal filter with a third-party HEPA upgrade. The factory version only includes carbon filtration, so adding HEPA makes a noticeable improvement for indoor printing.
Long-term, I plan to run a dedicated hose from the P2S external port directly to a window for full outdoor venting. But for now, this hybrid system works extremely well.

Even with a complete P2S filtration setup, it’s still not ideal to spend long periods in a small, enclosed room while printing. Some filaments are safer than others, but proper ventilation is always a precaution, not a perfect fix.
This setup simply lets me 3D print more safely and comfortably in my home office.

The official Bambu Lab P2S rear panel and external filter kit are expected to be available in the US starting in March, according to the Bambu Lab website.
If you have an early P2S and want a clean, effective P2S filtration setup that works with the Fnatr filter, this build is 100% functional. I’ll include the 3D print file for my custom reducer so you can copy this exact setup.

That’s my complete P2S filtration upgrade for the Bambu Lab P2S. If you have questions about the install, the Fnatr filter, or small-space 3D printing safety, drop a comment below.
Happy (and safe) printing!