So, as a hobbyist, I understand that these tiny wood particles are dangerous, but can you give me a ballpark as to how dangerous?
It depends on the specifics of the friable material and the range of particles being generated.
The damage from CNC dust is mostly lung damage, allergic reactions and immune system problems. Cancer is a remote but non-trivial possibility. CNC dust exposure is a serious issue; much akin to exposure to Asbestos.
Eye and nose irritation are not uncommon. One of the forum members noted immediate relief from nose and eye irritation once they started using negative pressure on the enclosure. No exposure, no irritation - or worse.
It’s also about exposure - how much for how long and how many times - and sensitivity (genetics). Like smokers, some are virtually unaffected negatively but most are affected and some are severely affected.
Because we know that the damage accumulates and we don’t know our (genetic) sensitivity, we need err on the side of caution. That said, we don’t have to go instantly frantic either. Study, read, prepare, budget and solve. All that can be done reasonable quickly.
I’ve got a cheapo 100 RIDGID 4 gallon shopvac from Home Depot, which is I assume not HEPA rated, with I think the 3 layer “fine dust” filter on it which is supposed to catch stuff .5+ microns (not small enough apparently),
Are you sure that’s 0.5 microns? They are often 5 microns. Please check!
Sadly, there is much lying around filter specifications. This is why the HEPA standard is around - no games.
and I don’t have an output hose, so that stuff is just spewing back out into my poorly ventilated computer room.
Without the proper elimination/filtration using a vacuum element can actually make things worse - instead of being somewhat contained the particles are now spread all over the place.
Can you vent out a window?
Take time to understand, learn the trade offs and make a plan.
From what I’m reading between this and the other thread, this is terrible and I’m probably breathing in all sorts of nasties when I open the enclosure to get at my work piece, and when I vacuum, I’m probably sucking up the nasty small bits and then just blowing them right back out into my room, except this time weaponized, probably giving myself lung cancer or something?
I’m afraid so. While the enclosure does contain the particles somewhat, there is leakage. As I’ve indicated in other threads, if one has a HEPA filter vacuum element but nothing else, one should slowly open the enclosure and vacuum the air first. Take your time. Then, vacuum the visible particles.
So, I understand the “ideal” solution would be to get some super expensive vacuum and vent it outside
There are many ways to achieve an “ideal” solution. Not all of them are expensive; some are more expedient than others. For instance, a Festool HEPA dust collector with an Oneida dust separator (cyclone) is around US$1000. One package, little work, known quality. Reliable, trustworthy solution.
The good news is that if this is outside your budget, smart, effective solutions can be constructed for a lot less - and a little machining.
and build a downdraft table
No need for a downdraft table… but it is one possible solution. IMHO, a dust head is simpler and has the advantage that it does a lot of the clean up while the mess is being created.
A downdraft also tends to accumulate a mess underneath. While one has to clean underneath periodically, a vacuum underneath will cause much more rapid - and dense - accumulation.
and place the Nomad in an enclosure with a vacuum dust head and who knows what else, but honestly… that’s probably not going to happen.
One can use the Nomad enclosure, CNC an inexpensive dust head themselves, use some tubing, an inexpensive dust separator and dust collector.
The vacuum can keep the Nomad enclosure at negative pressure - less than the outside - and not only remove the particles but also stop them from leaking out. Let the vacuum run for a few minutes after a job finishes and you’re all set.
So, to achieve an “acceptable level of safety” for a guy that’s not milling stuff for 10 hours a day for 2 decades… what do you think would be the sweet spot of “not too involved/expensive, doesn’t require drilling vent holes through my house wall, but gets me most of the way there”?
It depends on your particular genetics. Since this is unknowable, we must deal with no acceptable lower limit. ESPECIALLY IF ONE HAS CHILDREN AROUND.
Drill a hole in the enclosure, some tubing, machine a dust head, a cyclone, a vacuum element and one can get there for relatively little $$$
If you can exhaust out a window, there are some interesting solutions. The noise must be dealt with if you’ve got neighbors.
If I just bought a cyclone system like the one @FlatBaller got, and was careful about vacuuming the air in as I open the enclosure, will that be significantly better than what I’m doing since I assume most of the bad stuff will end up in the cyclone and not coming out the vent of the vacuum? Acceptably safe?
Yes, that is better. But not enough. A cyclone by itself, a trivial filter and exhausting outside IS a safe and acceptable solution.
I’ve noticed that when I close the Nomad lid, that the little puff of positive air pressure blows some particles from underneath the machine (the bits that have landed on my desk after having fallen through the slots on the floor of the Nomad) out the sides and back. I assume small nasties are coming out of there as well (and the larger bits annoyingly fly off the desk and land in the vent of my desktop computer). What if I sealed one side and made some kind of vacuum adapter on the other side so that I’m essentially sucking air from underneath the Nomad?
If you’re going to be safe, negative pressure is necessary. If you want to prevent spread effectively, a dust head is necessary.
If I plug the back, prop open the lid a little bit to let the air flow in that way and have it get sucked down and out through the side vent, and with the majority (I hope?) of the small bits caught in the cyclone thingy, do you think that would be acceptable?
The cyclone is a serious improvement of a vacuum. 98%
I would not work with just a cyclone and exhaust inside. YMMV.
Or should I really bite the bullet and get an actual HEPA rated vacuum, and build the vacuum head, drill a hole through my lid, etc.?
Without a HEPA filter (or a cyclone and exhausting outside), you cannot reach levels of known safety.
I can’t tell you that you’ll be safe without meeting the known and well studied criteria. I can’t tell you that you’ll be OK - like some rare smokers - or dangerously sensitive. This is managing risks.
Obviously, budget vs. risk must enter any situation. While one can spend their way out of a situation - go all out - and have a good solution with little effort, you CAN find a good solution that doesn’t go all out.
@patofoto has a design that is excellent and does not require touching the lid - a hole in the back, machine a dust head and some tubing. Pretty simple actually.
@FlatBaller has a design that is excellent and can be done without going through the lid either.
Then one needs to deal with the air - dust collector, dust separator, and tubing. This does not have to be expensive. Some creativity, some shopping and some clever use of parts can achieve acceptable safety levels without a huge expense.
Time IS money and trading of time, materials and budget are necessary. Let’s find a good solution for you.