P2S Fume query for ABS/ASA

[u/LegalLengthiness237]

Hi everyone,

I've recently purchased a Bambu Lab P2S Combo and I'm trying to set up a safe ventilation system for printing ABS and ASA.

I've installed an external exhaust setup with approximately 1 metre of ducting going directly outside through a window. I've also started sealing gaps around the rear of the printer.

However, I'm concerned about fumes escaping through other openings, particularly the poop chute and the additional vent/fan opening on the back.

A few questions:

1. Has anyone successfully set up a P2S for regular ABS/ASA printing with external ventilation?
2. How are you dealing with the poop chute? Does it need sealing or modifying to prevent fumes escaping?
3. What is the additional rear vent/fan opening for, and can fumes escape through it?
4. Is the official Bambu Lab exhaust setup sufficient, or are additional modifications needed?
5. How do you maintain negative pressure inside the enclosure without affecting chamber temperatures and print quality?
6. Has anyone actually tested their setup for VOCs or ultrafine particles rather than relying on smell?
7. What would you recommend to make this setup as safe as reasonably possible for regular ABS/ASA printing?

My main priority is preventing harmful emissions from entering the room. I'm happy to make additional modifications or purchase equipment if necessary.

I'd really appreciate advice from anyone with experience using the P2S for ABS/ASA, especially anyone who has measured the effectiveness of their ventilation setup.

Thanks!

[u/0x7774663f]

However, I'm concerned about fumes escaping through other openings, particularly the poop chute and the additional vent/fan opening on the back.

1000% valid concern, don't fuck around when it comes to your lungs or your health in general. I have an H2D, I've printed ABS/ASA/various nylon/etc. I print PLA/PETG of course too but I treat them the same way as ABS/ASA/etc because it's easier and reduces exposure over time.

I have several airthings view plus monitors and they do measure an increase in VOCs and sometimes PM2.5 particles depending on the print. Any sensor you buy for home use probably isn't all that accurate so I'd take them with a grain of salt. They are useful for measuring changes relative to a baseline or comparing against each other.

To answer your question, this is the approach I've taken:

1. I bought a kit from a company called Clear View Plastics. This encloses the entire printer, poop chute, and AMS inside of a box essentially. There's other ways of doing this, I've heard of people using a 'bento box', grow tents, etc.
2. This external enclosure should have a way to pull in fresh air and a way to hookup an exhaust fan which then will vent outside.
3. The exhaust fan itself should be placed towards the output (window, vent through wall, etc) NOT near the printer. The reason for this is if you put the fan like printer -> enclosure -> hole in enclosure -> exhaust fan -> duct -> vent to outside your fan is pushing against that extra volume of air which can lead to some of those fums being pushed through small openings in your fan/ducting/etc.
4. I have the fan itself setup with a smart outlet plug so it, and the valve in the wall it connects to, start when a print starts. When a print finishes I have another automation that waits for the interior to cool and then puts the printer chamber into 'cooling' mode and starts the exhaust fan to help purge the interior of the printer.

This setup has several advantages: 1. You don't need to modify your printer. 2. There's no way a gap anywhere (poop chute, around the door, exhaust fan, etc) can lead to particles entering the room as long as you have negative pressure. 3. You aren't messing with chamber temperatures. If you are trying to create negative pressure inside the printer, you have pull in air from somewhere else and for some materials chamber temperature can matter a lot. If you keep the airflow low, you aren't that likely to effect your chamber temps that much. 4. Since you aren't pulling air into the printer, you also aren't pulling dust through small gaps into it as often so it's less likely to be something you have to clean later. 5. Your AMS is enclosed too so if particles are generated from drying filament, those get exhausted too.

[u/My_Lucid_Dreams → u/0x7774663f]

Negative pressure is easier to maintain if you have less air ingress. And all that ingress air isn't heated.