I’ve a decent sized shop vacuum which runs through a Dust Deputy and then to the dust skirt on my machine. I hang the hose from the roof and use a 1metre (3 foot) section of pool filter hose to join them together. This works really well.
However, it also builds a pretty decent static charge during cuts which, although relatively low likelihood, has the potential to cause fires and dust explosions.
My thought was to get some uninsulated fine copper wore, and to wind it around the hose (following the spiral) and have the ends wrapped in foil or something similar. The wire will be connected across all hoses, back to the earth back on the vacuum body.
My question is this: will doing this help dissipate the static or will pulling the dust through what is basically a wire coil, generate even more static? I’m recalling the fun we used to have with a Van der Graaf generator…
I don’t remember where did I read about very scientific information about this. I was worry about static explosion at the beginning. I always work with mechanical equipment, just met with woods. On that page was talking about how you can cause cycle regenerate static electricity while you’re trying to ground it. Graphics were showing between grounded and un-grounded shop equipment with real time test. Unfortunataly, grounded system was giving 45% more static, because of periodic static back-flash from the ground.
Only one ststem was very interesting, it was battery bank static generator. Because, charging system never give power back from power source incoming. System basicaly connecting with coper wires directly to holding battery bank.
Final word was more interestingly, Equipments without Static ground system were found safer than wired equipment. I think best practice is to dump dust collection daily and pray for the safety.
@AndyPreston I’ve been looking for some anti-static hose, but because the pool hose I have is a perfect fit and it comes in hand one metre lengths, I’ve been trying yo make do with what I’ve got.
@AlanDavis - I did try earthing the hose that comes with the shop vac which essentially did nothing. I assume that because the hose is non-conductive, earthing it at one point isn’t terribly effective.
Beside the relatively low risk of fire or explosion (although I know of a sawdust explosion at a sawmill where I grew up which injured some men and burned the place down), I’ve also received a static shock from the frame of the XCarve during a long cut, which both annoyed me and made me wonder how exposed my Arduino is.
Even with my limited knowledge of electronics (at the level of "don’t let the smoke out of the wires") I know that electronics and static don’t go well together.
I’ll check, but the thought has just occurred to me that earthing the frame of the machine is probably not such a bad idea. If the metal casing of the power supply is earthed, maybe I’ll just add a jumper to that.
I’m by no means an expert in anti-static tech, but you could look into how ESD mats work. From my slight bit of understanding is that they have a resistor in line to earth to help dissipate the electrical charge.
Honestly I have never even considered this, but now that you bring it up, looks like something I should look into.
@AlanDavis. No misunderstanding, I was simply thinking (typing?) out loud, albeit not terribly coherently. I’ve found a lot of help on these forums just by throwing ideas out there and seeing what replies I get from some of the more learned folk.
Whilst I’m reasonably competent in putting a nut onto a bolt, electricity is something of a black art, which, just when I think I have a tiny bit of understanding, turns out to have another whole set of properties I’ve never even considered.
Short jobs where I hold the hose and manually vacuum up the swarf, are not a problem, but when I walk up to my machine mid-job, and all the hairs on my arms & head start lifting up, and then I see bits of sawdust jumping a foot or so back & forth between the vacuum hose and the table, I begin to think "this is something I need to manage a little better".
I’m pretty sure it’s a simple fix, I just thought I’d ask to see if there were any pitfalls or more effective solutions.
Of course, that’s my hope too. I wish I can learn more. All my experience is controling static body electricity not to shock electronics on the equipment. But this is different, we’re not talking about damaged boards, if it is fire hazard, we have to take it seriously. Besides, if we have no protection and some incident happens, even Insurance Companies won’t pay a penny. I’m following you as always. Cheers.
Ok, I’m guilty of just skimming through this thread so if I missed something, apologies offered.
As a SERIOUS hobbyist wood worker, I run a 1 1/2 hp dust collection system in my shop with dedicated ducting to stationary tools including the XC and I don’t run grounding wire. I can get a bit of a jolt from my drum sander’s DC hose while in use but never enough to generate a spark
In the woodworking circles this subject has come up time and again and the risk of a dust explosion has been determined to be virtually non-existent. The airborne dust levels would need to be so high that one would not be able to see more than 1-2 feet through the haze for it to support that kind of combustion.
Unless someone were to push an XC to insane levels and maybe not even then, that sort of dust production isn’t even likely. The health hazards of breathing that fine airborne dust are more of a concern.
Fro another perspective however, static electricity doesnt really play well with sensitive electronics. Running a ground wire and grounding out to an outlet plate cover screw or other suitable ground point may not be a bad plan to protect the arduino/gshield and prevent erratic operation of the XC from the stray voltage.
Great topic, I actually went to take off the hose to unclog it during a few jobs and got a jolt each time and couldn’t figure it out, was looking for loose wires etc… Static electric never crossed my mind I can say it gives quite a jolt.
LOL, sorry to find humor in that because getting shocked is never enjoyable, but I couldn’t help but think what a perfect conduit for dissipating static in the hoses, just ground yourself out to the hose and be done.
I too have been contemplating different ways to control static with my dust cyclone, all i keep thinking about is the mythbusters episode where they built a giant capacitor out of a giant pvc pipe, charged capacitors equal bad day fast!
I followed this issue closely back when I was getting into woodworking. I am convinced that the risk of an explosion due to using plastic dust pipes is essentially zero. Here is an article from someone more qualified than me that sums up the issue rather well
Yes, but here we’re talking about a static charge that might pass to delicate electronics unless dissipated. Anyone who has used flexible plastic hoses to connect shop tools has felt the effect of the static buildup, unless the hose has a reinforcing wire that can be grounded to the dust collector. In the case of PVC rigid pipe, similar static charge buildup will occur and some prudent folks add a bare drain wire to remove the charge. In a workshop where the pipe of either type is connected to large machines, the effect on them is mostly non-existent. No, there hasn’t been a documented case of explosion from unprotected plastic pipe, but folks have reported getting a jolt from it. That jolt could create an issue with electronics such as those on a CNC.
I don’t know a whole lot about it, but it seems to me that to damage the electronics, you would need to pass that jolt to a conductor connected to the electronics. Or, in a worst case scenario, build a charge so great that it could arc through an enclosure to components on a pcb board. Perhaps having all pcb boards and wiring (stepper motors, etc) shielded with a grounded conductor would give good protection. Most modern chips are designed to give some level of ESD protection, and this can be enhanced by using on board fuses, clamping diodes, etc. I’m not sure to what extent the GRBL shield does this, or how robust the protection is on the DRV8818 chips. I glanced at the schematic of the GRBL shield and didn’t see anything that looked like ESD protection. Again though, I’m not an expert.
These types of discussions come up from time to time in woodworking forums. There are always two sides, of course. The way I see it, one can dig in their heels and do something AFTER they have an “incident” or one can buy some cheap insurance and use some protection. It’s your choice!
Now, having said all that I have, when I installed my 3hp Super Dust Gorilla I used metal pipe for all of my runs. No problem with static charge there!
I had a significant problem with static generation on my planer and shop-vac dust collection system myself, that thing would give some NASTY shocks! I ended that by just adding a piece of fine copper wire zip-tied to the hose, running down the side of the dust deputy to the ground where I have a nut dragging behind the vacuum. Not the most elegant solution, but it works well for me. Perhaps a variant of that, only grounded to a mains ground or something, since if it is indoors, you are not likely to have a convenient bare concrete floor for your ground weight to drag on…
Short jobs where I hold the hose and manually vacuum up the swarf, are not a problem, but when I walk up to my machine mid-job, and all the hairs on my arms & head start lifting up, and then I see bits of sawdust jumping a foot or so back & forth between the vacuum hose and the table, I begin to think “this is something I need to manage a little better”.
I am having a problem with the job quitting on my halfway through when I use the vacuum and I know I dont have that much static build up.
Many electrical and electronics parts suppliers carry rolls of adhesive foil tape which is around ¼" wide. Use this to create an “Earth strap” so you can collect all this charge and run it to earth (ideally via the earth pin on your electrical supply).
My vacuum hoses are a kind of ‘spiral wound’ design and so I’ve held the tape on by winding a length of string around the spiral as I applied the tape. A little tedious, but a nice unskilled job to consume a bourbon over. Making sure there is a connection between each hose, the dust skirt and my dust deputy means I now have zero static (and really funky looking hoses 'cos I used bright pink string).
Both me and my arduino, really really hate electric shocks. Me most of all…
I am about to put together a Dust Deputy and was looking into grounding options. Some people use internal grounding, some use external. This grounding kit instructions refer to both: internal as main grounding, external as extra.
I think I have a fundamental gap on how external grounding works. Assuming our hose is non-conductive and the static build up is happening on the inside, why do we need to ground the outside?
the staic charge builds up in the dust hose itself. I am not certain what benefit is gained by one method over the other. I run a DC system in my shop and the only static control I use is at the XC itself due to the electronics And that is a fine wire wrapped around the dc hose and run back to the cover plate screw on the wall outlet.
The most I have ever had in terms of a DC hose shock is at my drum sander. But that moves 10 times the amount of really fine dust that the XC does and even then it’s rarely any worse than a carpet shock on a dry winter day.