Within the past two months we’ve covered two separate incidents of 3D printing-related fires. One was caused by an ill-advised attempt to smooth a print with acetone heated over an open flame, while the other was investigated by fire officials and found to have been caused by overuse of hairspray to stick prints to the printer bed. The former was potentially lethal but ended with no more than a good scare and a winning clip for “Hacking’s Funniest Home Videos”; the latter tragically claimed the life of a 17-year old lad with a lot of promise.
In light of these incidents, we here at Hackaday thought it would be a good idea to review some of the basics of fire safety as they relate to the home shop. Nowhere was this need made clearer than in the comments section on the post covering the fatal fire. There was fierce debate about the cause of the fire and the potential negative effect it might have on the 3D-printing community, with comments ranging from measured and thoughtful to appallingly callous. But it was a comment by a user named [Scuffles] that sealed the deal:
“My moment of reflection is that it’s well past time I invest in a fire extinguisher for my workstation. Cause right now my fire plan pretty much consists of shouting obscenities at the blaze and hoping it goes out on its own.”
Let’s try to come up with a better plan for [Scuffles] and for everyone else. We’ll cover the basics: avoidance, detection, control, and escape.
As we mentioned, [Dan] is no stranger to 3D printers. His addiction has progressed so far that he needs bigger and bigger parts, but when he looked at the price of printers that could sate his thirst… it wasn’t good. We assume this is the time he decided to leverage his resin printer procrastination to build a massive printer for himself.
The frame is aluminum extrusion. The bed is an 1/4″ thick aluminum plate supported just a little bit in from each corner. He can use the 4 motors to level the platform, which is a killer feature on a machine this big. More or less it’s fairly standard mechanically.
We are interested in his interesting addition of a FLIR thermal sensor to see live heat distribution. We also applaud him on his redundant safety systems (such as a smoke sensor that’s separately powered from the machine).
All the files are available on his site if you’re procrastinating on something and would like one for yourself.
Thankfully it’s rare that we report on something as tragic as the death of a 17-year old, but the fact that the proximate cause was a 3D printer makes it all the worse and important for us to discuss.
The BBC report tells of a recently concluded coroner’s inquest into the December death of a young man in a fire at his family’s magic shop in Lincolnshire. The building was gutted by the fire, and the victim died of smoke inhalation. The inquest found that he had been working with a 3D printer in the shop and using hairspray to prepare the bed, a tip he apparently picked up from forums and blogs.
Unfortunately for this young man and his family, the online material didn’t mention that hairspray propellant contains volatile hydrocarbons like propane, cyclopropane, n-butane and isobutane — all highly flammable. Apparently the victim used enough hairspray in a small enough space to create an explosive mixture of fuel and air. Neighbors reported a gigantic fireball that consumed the shop, which took 50 firefighters to control.
While the inquest doesn’t directly blame the 3D printer as the source of ignition — which could just as easily have been a spark from a light switch, or a pilot light on a water heater — it does mention that the hot end can reach 300C. And the fact remains that were it not for the 3D printer and the online tips, it’s unlikely that a 17-year old boy would be using enough hairspray in an enclosed space to create what amounted to a bomb.
By all accounts, the victim was a bright and thoughtful kid, and for this to have happened is an unmitigated tragedy for his family and friends. This young man probably had a bright future and stood to contribute to the hacker community but for a brief lapse of judgment. Before anyone starts slinging around the blame in the comments section, think about it — how many time haves you done something like this and gotten away with it? This kid got badly unlucky and paid the ultimate price. Maybe we should make his death worth something by looking at what we do that skates a little too close to the thin edge of the ice.
Sometimes the best way to learn is from the success of others. Sometimes failure is the best teacher. In this case we are learning from [Tim Trzepacz]’s successive failures in his attempt to solder one board to another using a reflow oven. They somehow cancelled each other out, and he ended up with a working board. For those of you who have used a reflow oven, there will be eye rolling.
[Tim]’s first mistake was to use regular solder instead of paste. We can see how he got there logically; if you hand solder an SMD you melt solder onto the pads first to make it easier. However, the result was that he had two boards that wouldn’t sit flat on each other thanks to the globs of solder on the pads.
Not to be deterred, he laid the boards on top of each other and warmed up the oven to a toasty 650 degrees. Well, not quite. The dang oven didn’t turn to eleven, so he figured 500 would probably work too. Missing the hint entirely, he let his board bake in a nearly 1000F oven until he noticed some smoke which, he intuitively knew, definitely shouldn’t be happening.
The board was blackening, the solder mask was literally bubbling off the substrate, people were coming over to see the show, and he decided success was still possible. He clamped the heated boards together with a binder clip until they cooled. Someone gave him a lesson on reflow, presumably listened to through reddening ears.
Ashamed and defeated, he went home. However, there was a question in his mind. Sure it looks bad, but is it possible that the board actually works? After a quick test, the answer was yes. It loaded some code and an time later he was happily hacking away. Go figure.
One of the installations that consistently drew a large crowd after dark at EMF Camp 2016 was a game. This wasn’t a conventional computer game though, instead it was a line of gas jets along which a pair of players had to bat a jet of flame between them at ever-increasing speed until one player missed the return. This was the Fire Pong game created by members of Nottingham Hackspace, and though there seems to have been no online write-up of it as yet they have posted enough pictures of its build for us to deduce something of its construction.
If you will excuse the quality constraints of a mobile phone camera in a darkened field, a video of the game in action is below the break. There was a significant queue for a turn at the bat, this was one of the event’s more popular night-time attractions.
Our 2014 adventures were so much fun that it drove us to create our own hacking challenge in 2015 to cobble together a <$100 HF SSB transceiver (made in the USA for extra budget pressure), an ad-hoc antenna system, put this on the air, and make an out-of-state contact before the end of Hamvention using only parts and gear found at Hamvention. There’s no time to study manuals, antennas, EM theory, or vacuum tube circuitry. All you have are your whits, some basic tools, and all the Waffle House you can eat. But you have one thing on your side, the world’s largest collection of surplus electronics and radio junk in one place at one time. Can it be done?
We posted about a 3D printer fire a while back. An attendee of the Midwest RepRap Fest had left his printer alone only to find its immolated remains on his return. In the spirit of open source, naturally, he shared his experience with the rest of us. It occurred to me that hackers are never powerless and there are active things to be done and avenues to explore.
There are really fantastic commercial fire extinguishing systems out there. One implementation, which is commonly deployed in cabinets and machining centers, is a plastic tube pressurized with an extinguishing agent by a connected tank. When a fire breaks out the tube melts at the hottest locations, automatically spraying the area with a suppressant. Variations of this involve a metal nozzle filled with a wax or plastic blended to melt at a certain temperature, much like the overhead fire sprinklers.
This system is also used inside engine compartments with success. For example, this item on amazon, is nothing but a pressurized plastic tube with a gauge on one end. Since the inside of an engine compartment can be treated as an enclosed space, very little fire suppressant is needed to extinguish an unexpected flame. It is important to note that this system works in a high temperature environment like an engine compartment, which bodes well for enclosed build envelopes on 3D printers.
Another option is to construct a suppressant mine. A Japanese and a Thai company have both come out with a throwable fire extinguisher. In the Japanese device, the outside of the extinguisher is a breakable glass vial which shatters upon impact; releasing the agent. The Thai device looks like a volley ball, and releases the agent upon the application of heat. This device seems like a better candidate for 3D printing or home projects. Imagine a small rectangular pack with adhesive on one side that sits near the possible fire points of the printer, such as under the bed or above the nozzle. In the event of a fire, the casing will melt and the system will automatically deploy a spray of extinguishing agent.
Most of the chemicals used in these constructions are benign and readily available. High pressure tubing and waxes can all be purchased and the desired melt points can be aligned with their datasheets by need. Plastic sheets are not hard to procure. These offer a nice solution due to their entirely passive nature. They don’t need power to operate and rely entirely on the properties of the materials they are constructed out of.
There are other options in active systems. Hackaday readers suggested things such as flame sensors for adding automatic cut-offs in case of a fire. Thermal fuses can also be considered in some cases. There are other tricks too, which are less kosher but will work nonetheless. For example, placing a critical wire, fuse, or component in the likely path of a fire so that it is destroyed first, stopping the operation of the device quickly. These avenues should be explored. At minimum there should be at least one project that uses a Raspberry Pi and an Arduino to tweet that fire suppression failed and the house is on fire.
Some of the big questions to ask are on the legal and ethical side. If someone started selling kits for a DIY fire suppression system and a fire ends up destroying someone’s property despite the device, who is responsible? Is it even safe to post instructions? What if a kit prematurely sets off and injures someone. I imagine a big part of the cost of these professional systems is some sort of liability insurance and certification. Still, putting a six hundred dollar fire suppression system on a six hundred dollar printer seems silly, and something is better than nothing.
Lastly, the comments directed a ton of flak towards the certification systems. There should be no reason that open source projects can’t produce their own specification for safety. An open source specification without an agency naturally couldn’t provide a legal defense against property damage, but a thought-out test program would provide piece of mind. For example, in the case of 3D printers, one could have a set of basic fail-safe tests. One example would be bringing the printer up to temperature and rapidly disconnecting the thermistor, does the printer erupt into fire? No? Good, it meets the spec. I wouldn’t mind knowing that the latest version of Marlin was tested on the popular boards and still met the community specification for fire safety.
As far as I can tell, there’s been very little work in open sourcing safety systems or in providing a testing framework for ensuring open hardware meets basic safety conditions. Many of you have experience with these systems. Some of you have gone through the entirely un-enjoyable process of getting a UL certification. What does Hackaday think?