Glowforge marketed their laser cutter as a 3D laser printer, didn't they?

As someone waiting for their Glowforge to ship, I really hope their device wasn't involved in all this.

From Glowforge's website, for their base model:

> It needs ventilation via the provided 4″ diameter (10.2cm) hose. We recommend putting the hose out a window.

They also say:

> Lasers normally require some ventilation via a small tube out a nearby window. Our optional Air Filter that sits under Glowforge and ventilates using HEPA filters and charcoal, meaning no outside ventilation is required.

Best to my knowledge HEPA and charcoal don't help against CO. So running one with the filter in an unventilated space might still be hazardous.

"To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm."

Carbon monoxide is a few orders of magnitude too small to be caught by a HEPA filter, in fact a filter that could filter CO would filter oxygen and nitrogen as well. Such a filter would just be a pump.

There, however, exists a patent for a filter for CO, it works by converting the CO to CO2: https://www.google.com/patents/US5564065

Needing to eliminate CO is an old, well-solved problem. Even the cheapest catalytic converter would do so.

(It's not quite as simple as just putting one in-line with the waste gas flow- the catalyst would also need to be externally heated.)

It is possibly to filter gases of similar molecular weight. https://en.wikipedia.org/wiki/Membrane_gas_separation

This technique is routinely used to generate concentrated supplies of oxygen or nitrogen, but is wildly expensive compared to ventilation.

I'm guessing this is undergoing a hurried rewrite, to add something along the lines of 'or you may die.' they're gonna get sued out the yin-yang for this even if the dead couple totally ignored the instructions, on the grounds that the instructions didn't state the danger clearly enough.

Having said that, while good safety information is important, two MIT-trained engineers should really have known better.

Why should they have known better? He was a software engineer and she may have had exposure to lab technique but a Glowforge doesn't scream "needs an industrial hood" or anything. Yes, they clearly _could_ have known better, but 'should' seems to be making too-strong assumptions about their class work, MIT or other. They could have had economics degrees for all we know (less likely given their careers, but you get my point).

Yeah, while I get that the general public misses this, I'm surprised to see people who apparently think that "engineer" means a Star Trek-style omnicompetent generalist.

I dunno man, if something says you need to ventilate it by putting an exhaust hose outside, I figure there must be a good reason for that. I have a lot of hazardous chemicals in my house because I paint and a lot of artist paints have toxic ingredients. I read the safety warnings carefully even though I know little of chemistry.

It says you don't need to vent if you use the filter.

I read the safety notices that manufacturers affix to their products and take them at face value unless I have reason to believe otherwise. It seems kinda stupid not to.

And it said you don't need to vent if you use the filter.

Glowforge company is upthread, says the deceased were not customers of theres. Presumably it's a different brand of laser cutter.

That said, I'm assuming Glowforge is going to scramble to make sure that users use their device safely regardless.

... while all their marketing materials and videos show Glowforge sitting happily in the middle of a living room with absolutely no exhaust pipe.

I think the bigger issues is that these kinds of DIY maker tools are marketed as in-home. You wouldn't put a band saw in your spare bedroom-why do people use these kinds of tools in a normal house/apartment? Though two engineers living in Berkeley are probably not going to have a garage, alas.

Might be a laser cutter/engraver. Would make more sense since those actually do burn the material.

The CO2 laser tubes sold to hobbyists are sealed. There is no gas supply. Large industrial lasers use a gas supply in order to cut faster and at higher power.

Some home-built tubes do use a gas supply, but virtually no one builds their own CO2 tube to use in a laser cutter when better tubes are available on eBay for $100.

I never said anything about the laser tube. I think it's more likely they did use a gas supply and that leaked.

I've never seen or heard of a non-industrial laser cutter with a gas supply.

Air assist, yes (to clear smoke and particles from the beam and protect the focus lens from soot), but that's just an air pump, not a gas supply.

What would you use a CO2 supply for with a laser cutter or 3D printer then? I can't think of anything.

Maybe I misunderstand how CO2 lasers work. But my understanding is that a high-powered CO2 laser can be run using a gas supply from a tank/regulator. As mentioned elsewhere, this is typically only done in industrial settings, but some home laser cutting enthusiasts want more power. The tank contains some mixture of gases, primarily CO2, but containing other gases, likely some CO. If the tank/regulator to laser tube connection is leaking in a closed room, then the CO concentration in the air will increase.

This is speculation on my part based on my assumptions. If my assumptions are incorrect that's fine.

Yes, but those would feed CO2 into the laser tube, which I thought you just excluded ("I never said anything about the laser tube.").

As others have said, normal laser cutters have sealed tubes, although its of course possible they had some DIY rig for whatever reason. MIT students building their own CO2 laser just for fun doesn't seem all that odd, using it for long time in a cutter maybe more so. I don't know if a leak in a CO2 system would lead to CO poisoning or no. CO produced by the material cut seems more likely to me.

Sorry, I guess it is a bit unclear: I assumed the leak preceded the laser tube proper. When you hook a tank/regulator up to an evacuated tube, there can be leaks "before" the laser tube (I spent a month building vacuum chambers, and most of my leaks were in the connections between the vacuum pump and the chamber, not the chamber itself).

however, after thinking some more, I agree that CO from material cut is more likely.

The "gas supply" you're referring to is most likely an "air-assist". Laser cutting works better when you have a flow of air (just air), blowing the smoke out of the way.

Many folks use small compressors for this purpose.

But it won't have anything to do with CO levels.

CO poisoning is cumulative. It takes a long time for CO to get unstuck from hemoglobin. It could have snuck up on them slowly, then one evening with the cats "napping" they felt particularly tired and thought to themselves, "We must be in hibernation mode from the chilly weather," then they went to sleep then never woke up.

CO is odorless. You might get a headache, or you might only feel tired. What's worse: a lot of CO detectors are pretty shoddy.

Your description makes me increasingly worried; do you have any preferred CO detectors?

Avoid cheap ebay stuff. I think Consumer Reports have done a rating of those devices sometime. However, that might be out of date at this point. I just did a search on YouTube, and even those random reviews seem to date from 2014. There should be a way to verify those. Maybe Cody's Lab could handle this?

Co2 lasers are 30℅ CO by design. Kind of like a halogen cycle thing but recombinant.

There is very little gas in a tube though.

It seems the poisoning came from the operation of the laser, which means that the gases inside the laser were not involved. (It doesn't seem from breakage of the tube, but from usage.)

at other sources it is said that they had "laser cutter and 3D printers".