Hack Safely: Fire Safety in the Home Shop

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.

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Self-Driving Cars Are Not (Yet) Safe

Three things have happened in the last month that have made me think about the safety of self-driving cars a lot more. The US Department of Transportation (DOT) has issued its guidance on the safety of semi-autonomous and autonomous cars. At the same time, [Geohot]’s hacker self-driving car company bailed out of the business, citing regulatory hassles. And finally, Tesla’s Autopilot has killed its second passenger, this time in China.

At a time when [Elon Musk], [President Obama], and Google are all touting self-driving cars to be the solution to human error behind the wheel, it’s more than a little bold to be arguing the opposite case in public, but the numbers just don’t add up. Self-driving cars are probably not as safe as a good sober driver yet, but there just isn’t the required amount of data available to say this with much confidence. However, one certainly cannot say that they’re demonstrably safer.

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Path To Craftsmanship: Don’t Buy Awful Safety Gear

A while back I tried to make a case for good safety disciple as a habit that, when proactively pursued, can actually increase the quality of your work as a side effect. In those comments and in other comments since then I’ve noticed that some people really hate safety gear. Now some of them hated them for a philosophical reason, “Ma granpap didn’t need ’em, an’ I don’t neither”, or ,”Safety gear be contributin’ to the wuss’ness of the modern personage an’ the decline o’ society.” However, others really just found them terribly uncomfortable and restricting.

In this regard I can help a little. I’ve spent thousands of terrible long hours in safety gear working in the chemical industry. I was also fortunate to have a company who frequently searched for the best safety equipment as part of their regular program. I got to try out a lot.

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Toyota’s Code Didn’t Meet Standards and Might Have Led To Death

We were initially skeptical of this article by [Aleksey Statsenko] as it read a bit conspiratorially. However, he proved the rule by citing his sources and we could easily check for ourselves and reach our own conclusions. There were fatal crashes in Toyota cars due to a sudden unexpected acceleration. The court thought that the code might be to blame, two engineers spent a long time looking at the code, and it did not meet common industry standards. Past that there’s not a definite public conclusion.

[Aleksey] has a tendency to imply that normal legal proceedings and recalls for design defects are a sign of a sinister and collaborative darker undercurrent in the world. However, this article does shine a light on an actual dark undercurrent. More and more things rely on software than ever before. Now, especially for safety critical code, there are some standards. NASA has one and in the pertinent case of cars, there is the Motor Industry Software Reliability Association C Standard (MISRA C). Are these standards any good? Are they realistic? If they are, can they even be met?

When two engineers sat down, rather dramatically in a secret hotel room, they looked through Toyota’s code and found that it didn’t even come close to meeting these standards. Toyota insisted that it met their internal standards, and further that the incidents were to be blamed on user error, not the car.

So the questions remain. If they didn’t meet the standard why didn’t Toyota get VW’d out of the market? Adherence to the MIRSA C standard entirely voluntary, but should common rules to ensure code quality be made mandatory? Is it a sign that people still don’t take software seriously? What does the future look like? Either way, browsing through [Aleksey]’s article and sources puts a fresh and very real perspective on the problem. When it’s NASA’s bajillion dollar firework exploding a satellite it’s one thing, when it’s a car any of us can own it becomes very real.

Upcycle An Isolation Transformer

There are several reasons you should have an isolation transformer. They can prevent ground loops and also prevent a device under test from having a DC path to ground (or isolate an oscilloscope from DC ground, which can be dangerous in its own right, but that’s another discussion). [Tanner_tech] noticed that finding ballast transformers for sodium vapor street lights is getting easier as more street lights move to LED technology. What to do with these transformers? Build an isolation transformer, of course.

Of course, your dumpster transformer might be a little different than the one shown in the post (and the video, below). [Tanner] shows how to work out the leads you need. A little wood work and a PC power supply case finished the project.

Judging from the comments, some people take [Tanner’s] talk about safety as an implication that a transformer makes working on mains safe. It doesn’t. It makes it safer if you know what you are doing. Working with high voltage isn’t a place to learn by doing.

If you want some practical advice, [Jenny List] has a good read for you. You probably also ought to invest an hour in watching this video that has a lot of practical advice.

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Taming the Beast: Pro-Tips for Designing a Safe Homebrew Laser Cutter

Homebrew laser cutters are nifty devices, but scorching your pals, burning the house down, or smelling up the neighborhood isn’t anyone’s idea of a great time. Lets face it. A 60-watt laser that can cut plastics offers far more trouble than even the crankiest 3D-printers (unless, of course, our 3D printed spaghetti comes to life and decides to terrorize the neighborhood). Sure, a laser’s focused beam is usually pointed in the right direction while cutting, but even an unfocused beam that reflects off a shiny material can start fires. What’s more, since most materials burn, rather than simply melt, a host of awful fumes spew from every cut.

Despite the danger, the temptation to build one is irresistible. With tubes, power supplies, and water coolers now in abundance from overseas re-sellers, the parts are just a PayPal-push away from landing on our doorsteps. We’ve also seen a host of exciting builds come together on the dining room table. Our table could be riddled with laser parts too! After combing through countless laser build logs, I’ve yet to encounter the definitive guide that tells us how to take the proper first steps forward in keeping ourselves safe while building our own laser cutter. Perhaps that knowledge is implicit to the community, scattered on forums; or perhaps it’s learned by each brave designer on their own from one-too-many close calls. Neither of these options seems fair to the laser newb, so I decided to lay down the law here.

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Working with Mains Voltage: The Electrifying Conclusion!

This is the second in a two-part series looking at safety when experimenting with mains-voltage electronic equipment, including the voltages you might find derived from a mains supply but not extending to multi-kilovolt EHT except in passing. In the first part we looked at the safety aspects of your bench, protecting yourself from the mains supply, ensuring your tools and instruments are adequate for the voltages in hand, and finally with your mental approach to a piece of high-voltage equipment.

The mental part is the hard part, because that involves knowing a lot about the inner life of the mains-voltage design. So in this second article on mains voltages, we’ll look into where the higher voltages live inside consumer electronics.

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