When I acquired my 3D printer I was so excited to get started. I had done quite a bit of research before turning it on the first time or opening the first bottle of resin. But all the research was just not enough. People say that 3D printers smell. They are not kidding!
So many articles, videos and websites said that just putting your printer in a well-ventilated room would be sufficient. Unfortunately, that is really not the case. If you can smell it, you have already been exposed to hazardous and poisonous "Volatile Organic Chemicals" (VOCs).
VOCs can have different effects on different people. Some will be sensitive enough to it for it to cause mild respiratory symptoms, headaches, or dizziness. But even if you experience no symptoms at the time of exposure it is still a long-term risk for cancer. There are not a lot of studies done yet on the long-term effects of VOCs from resin printing. However, the warning signs are there. This is not a toy and can be very dangerous.
Ideally, you would have a separate room (such as a shed, garage or spare room) away from your family, pets and common living areas. VOCs are heavier than air so they sink to the ground, covering every surface they land on. In a situation like apartment living or a small space, you have to be extra careful of the contamination of your frequented areas.
These are some of the things I have done to protect myself and my family while using my printer.
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The Enclosure
My research seemed to imply that I could just put something around the printer (a cabinet, a tent, a box) with a vent and a fan to filter exhaust from the enclosure to a window. While this did work (somewhat) it was just not enough.
Let me explain.
I have an Elegoo Saturn. The unit itself stands approximately 24" tall, and is 14" x 13" around. It is not a small machine to begin with. But not only does the machine off-gas VOCs, but the uncured resin itself is also dangerous. So I needed a space that was large enough to fit the printer, several bottles of resin and also large enough that I could maneuver around inside it to keep everything contained.
Insert "Grow Tent". Indoor grow tents are already set up for having exhaust pulled from them. They have easily sealable pull-string ports on all sides and even a sturdy frame that can support a light or filter. Some Grow Tents on Amazon even have the exhaust fan and ducting included.
So I have a large enough enclosure. The tent measures 24"x 24"x 48". This should leave enough space around the unit to store several bottles of resin and other tools. I need at least 16' of ductwork to reach from the tent to the fan and from the fan to the window and a strong enough fan to pump exhaust out of the tent and out of the window before it can escape into my living area. But I cannot just have a window wide open.
Not only do I live in a very hot state and don't want to be paying to cool the outside with my Air Conditioning, but also that would kinda defeat the purpose as the exhaust will just come right back in through the open window. So we need something to put in the window that will help block it off so the exhaust goes directly out and has no chance of coming back in.
A trip to Lowes and a bit of sanding later I have a wood board with a hole cut to fit the exhaust duct into that fits the exact dimensions of my window. This should work.
But alas, I start up my printer and WHAM the smell is so strong it has us opening all our doors and windows trying to air it out (good thing it was winter).
I check everything and check everything again. The tent has positive pressure airflow. The off-gas could not escape out the tent. The fan is pointing the right direction, so no way I am blowing it back into the house. The window fitting is secure and I put on an extra layer of duct tape just to be sure. But still... It smells terrible!
This is where I found the hole that all my research did not fill. I knew if I was smelling it, I was poisoning not only myself, but my family and my pets. I had to find another way.
I did more research and found that a filter might help. I skimmed all the reviews on many different filters for a grow tent. They are made to completely get rid of and filter out the smell of growing plants. Why wouldn't it also help filter the air of VOCs? I found one that seemed like overkill. HUGE, barely fit in the tent. But I have to say, that one beautiful thing made all the difference!
So my conclusion is that an enclosure with positive pressure and exhaust piped out of the house through a window just is not sufficient. You also need to filter the air as it is removed from the enclosure. Now I can run 5-6 hour prints with no smell whatsoever. I feel safe knowing that I am not poisoning my loved ones with my hobby and I can freely create and print whatever I want!
Air Purifying
Ok, so I have the printer itself contained and not leaking harmful chemicals into my living space. But what about post-processing? Even just the uncured resin itself off-gasses. So my print gets done in the tent and then what?
First off, put any pets away in another room. Because the VOCs sink to the ground they are the most susceptible to getting a large dose of potentially cancer-causing chemicals.
Second, Air filtration and ventilation. Because I live in an apartment and in a very hot city, it can be very difficult to just leave the door open. But for the 20-30 minutes of post-processing I take the risk. I turn off my AC to stop the fan from pumping chemicals into the rest of the rooms. I put floor fans pointing out the door to pick up and take the harmful chemicals from my workstation, right out the door and I set up several air purifiers right next to my workstation. This takes care of the bulk of it.
Third PPE! (Personal Protective Equipment) Protection is key. If I cannot remove myself and my family from the room (like I did the pets) I have to make sure we are protected. Only the right personal ventilator mask will properly filter VOCs. I will leave links to the ones I use. Remember, if you can smell it, it is already too late. Your mask should fit securely and completely eliminate the smell. The filters last a limited amount of time. Remember if you start to smell it, even just a little bit, you are not being protected and need to immediately replace your filter.
This is the ventilator I (and my family) use while I am doing anything with uncured resin
and These are the replacement filters for it.
Cleanup
The liquid resin used in an SLA printer is toxic. Like REALLY toxic. It can burn your skin, irritate your eyes, and you do NOT want to ingest it, not even the tiniest of trace amounts. For this reason, you need to be sure that anything it touches is very thoroughly cleaned.
Wear gloves!! Although disposable gloves are not my preference I have not found a brand of reusable nitrile gloves that allow for as much dexterity as I need when cleaning and processing very small printed dice. So I use disposable nitrile gloves and change them any time I need to touch something that is not already known to be contaminated.
Prepare your workspace before you even open the enclosure!
The most annoying thing is being so excited to see the beautiful new things you created that you forget to prep your work area and find yourself scrambling to try to contain dripping resin while having to take off and put on new gloves several times to touch everything you forgot to prepare before starting.
I stock my work area with all the towels, paper towels, extra gloves, tools, brushes, IPA (Isopropyl Alcohol), containers and spray bottles and make sure my lighting is up and ready to see those small details. When I pull the print I want to already have every paper towel in place, every mat ready and every tool easily within my reach so when I sit down to post-process, everything goes quickly and smoothly. I do not want to have the exposed, off-gassing uncured resin out any longer than I have to. The less exposure the better.
Dispose of your waste responsibly!
When I get done carefully cleaning each of my tools and workspace I wrap every dirty paper towel and resin-covered cloth into a zip lock bag and expose it to either sunlight or my cure box for several minutes before throwing it away. All of my now-cleaned tools get put back into the tent with the printer that is sealed and constantly has a very small amount of air being pulled through the duct to exhaust so none of it leaks out into my living area.
Every surface that resin touched or that something covered in resin touched gets thoroughly cleaned and the whole area is inspected in bright light to be sure that nothing was accidentally dropped to the floor before the pets are allowed back into the area.
Now you may think some of my methods are overkill. Perhaps they are. But because I have such a small space to work in, with the printer sitting literally 5 feet from where I work every day, every bit of precaution is important. I love my family and my pets and would never want to harm them, make them sick or cause cancer because I want to print cool things.
I hope that my experiences and failures can help you be better at your craft too. If you have any questions or methods that I have not tried I would love to hear your feedback!