Holy Mola, Laser Cutters! If you follow me on Instagram, you’ve probably seem some pretty cool projects coming out of my freshly arrived Glowforge laser cutter.
But laser cutters are not all sunshine and cool, wooden hinges. Laser cutters were, until very recently, the domain of industrial fabrication shops with extensive safety systems. As a new generation of low(er) cost, hobby and household cutters enter the market, we need to step back an think critically about the potential health and safety impacts of these incredible machines.
Like I did with 3D printers a few years back, I’m taking a deep dive into the hazards of laser cutters in the home and how to avoid them.
First, the issues of least concern (not because they aren’t bad, just that they’re far less likely to occur).
Fire. Lots of materials can catch fire, including, to no one’s surprise, wood. A fire safety plan will go a long way, but you can avoid ruining your laser cutter by being aware of what materials frequently catch fire. ABS, HDPE, polystyrene and polypropylene, and anything with poor thermal properties is going to ignite rather than cut cleanly. And then you’re going to have a bad day.
Beam escape. If your machine is not well taken care of and well shielded, there’s a small chance the wrong materials or loose connections can result in a beam escape, which can injure the user, bystanders, pets, or anything else that gets in the laser’s path. Most hobby grade lasers have good safety features to prevent this (although cheap knock-off machines are starting to hit the markets that may not be up to par), but monitoring you equipment and keeping it properly maintained will go a long way to avoiding this.
But those aren’t the biggest concerns. Th biggest concern with laser cutters is the byproduct that happens every time you cut, no mater what. That’s right, I’m talking about:
This is the big one and the issue that I’m most concerned about. Laser cutters haven’t really left industrial settings until now, so we don’t have very good data on chronic exposures of laser cutting fumes, especially on young children and pregnant people. What we do know is that the fumes produced by laser cutter depend heavily on the materials you choose to cut.
All materials will produce fumes when cut, which is why it’s essential that your set-up is well-ventilated. Most hobby cutters have a vent port that you can connect to a dryer vent or to the outside. I actually don’t recommend using a dryer vent. In all the rental houses I’ve lived in, not one has ever had the dryer properly vented, and hooking up to your dryer port might mean that you’re just venting into the crawlspace or the wall, rather than out of you house. Go for the window. There’s no hard and fast rule for how much ventilation you need, other than as much as possible. For 3D printers we recommended that your ventilation system moves 3 times as much air as the volume of the room per hour. For laser cutters, it should probably be more.
Everything you cut is going to release volatile organic compounds (VOCs), which is why ventilation is essential. For things like hardwoods and paper products, the VOCs released are comparable to a woodburning stove, frying too much bacon, or sitting around a campfire (though sitting around a campfire will give you a much higher dose). Prolonged exposure can cause respiratory problems and asthma. More complex materials like plywoods and plastics can have some pretty nasty compounds, so you want to make absolutely sure you know what’s going into your laser cutter, be aware of what materials should never, ever go into you household cutter, and always ventilate, ventilate, ventilate.
A non-comprehensive list of materials you absolutely should not cut using a home or hobby laser cutter.
PVC. Polyvinyl Chloride. Chloride is right in the name. Cutting or engraving PVC emits hydrogen chloride, dioxin, ethylene dichloride and vinyl chloride. These gases will ruin you day, likely destroy your machine, and cause severe acute and chronic exposure problems, including cancer, as well as damage to you neurological, reproductive, and immune systems. PVC is especially concerning because it is so widely available in home improvement and hardware stores.
Polycarbonate. Polycarbonate is produced using phosgene, which is not really something you ever want to be exposed to. It’s not clear to what extent cutting polycarbonate remobilizes phosgene, but polycarbonate in general is not a great material for laser cutters, anyway (it has poor thermal properties and smells like death), so it’s best to avoid. Be careful though, as some suppliers will mix up acrylic and polycarbonate.
Polyethylene. Polyethylene is one of the most common plastics in the world. When exposed to lasers, it releases formaldehyde. Acute exposure can induce asthma attacks and cause respiratory damage. Chronic exposure to formaldehyde causes cancer.
Rubber. Rubber, when exposed to high-energy lasers, emits benzene. Benzene is a carcinogen and prolonged exposure can cause serious health problems. Many rubbers also release chlorine gas.
Food. Unless you have a laser cutter specifically set up only to cut food products, maybe don’t slip something you’re going to eat into the same machine that’s been carving through plywoods and plastics.
The X-factor. It’s not the fancy polymers that really scare me. We know what’s in them and what happens when you shoot a laser at them. Materials like PVC can be extremely hazardous. If you don’t know PVC produces hydrogen chloride gas, dioxin, and a host of nasty carcinogens, you really have no business running a laser cutter.
The material that really scares me is one that is so common and so deeply embedded in the Maker Movement, that we barely even think about it. Abundant and practically free, it’s the darling of cheap builds and kitschy craft project. It goes into frames and furniture and coffee tables and utensils and even cribs.
As laser cutters begin the transition from industrial hardware to in-home fabricators, the material that gives me the most pause is the lowly, worldly, used shipping pallet.
Pallet wood is nasty. Depending on where and when the pallet was made, it could be treated with methyl bromide. Sure, there are ways to check whether a pallet was heat treated or treated with methyl bromide, but that’s only one of a near infinite number of ways a pallet could be impregnated with carcinogens or other toxin chemicals. Pallets travel the world in the holds of every vessel you can imagine. During voyages, they could be exposed to hull cleaners, oils, dispersants, and that’s not even taking into account what they were used to ship with. Loading docks, freight trucks, and rail cars also tend to not be the least hazardous environments in the world. In short, it you don’t absolutely know the history of a pallet, you really have no idea what’s lurking inside it that could mobilize into the air the moment you start cutting.
This really goes for any reclaimed material that you don’t know the history of, but pallets are uniquely situated to come into contact with, well, basically everything the human race has mass produced since 1949.
So what should you do? Hobby laser cutters are great and will open up a new world of making just like the 3D printers before them. Understanding where the potential hazards lurk goes a long way towards ensuring your and your family’s safety. When running a laser cutter, Ventilation is your God. Glowforge has been putting a ton of effort into ensuring its Proofgrade materials are as safe as possible. For me, I avoid running large projects when the kid is in the house (just in case) and ensure there’s a ton of airflow in my workspace. If you’re using new or unfamiliar materials, research them thoroughly.
And maybe give that pile of used pallets a pass.
Be safe, and make great things!
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