In my quest to tame static ond clumping in coffee grounds while brushing out my Rocky ( "I civilized my Rocky" ) I recently had a thought. The bristles of the brush should be electricly conductive.
Does anyone make a brush suitable for brushing out coffee mills which is conductive?
Sorry, I always feel a need to weigh in whenever the topic of static comes up. It is the one thing discussed in the forums that I have some expertise in. Forgive me if I get too pragmatic on the subject, but it is how I pay the bills.
The thing about static is that it needs a path to ground in order to drain off the charge. These brushes are conductive, but to what? They are designed to be used on electronic work surfaces where a ground is already in place through the wrist strap. You holding a brush and standing in rubber soled shoes is not a path to ground. For these to work properly you should either wear a static wrist strap or be touching a earth ground the whole time you are using the brush. If not you are taking on the charge and will get the old doorknob shock as soon as you touch your machine.
I would recommend you do more in grounding the griner, chute and hopper. This is the best route to static elimination on a grinder.
Now that I think about it further, one way the brush would help is if you ground it to the machine and mount it just above the chute where the ground coffee comes out. This would act as a "passive ionizer" and might just take the charge off the ground coffee. It would be hard to keep clean, but it might work when it is clean.
Sure, but you're probably standing next to the kitchen sink, unless you make your coffee in a very unusual place. It shouldn't be too difficult to provide a path to ground....
The conductive bristles would be touching the filter basket and / or the metalic funnel of my "Civilized Rocky" and therefore be at their potential.
I actually am planinng to attach a lead to the brush which will connect to the frame of the machine for when I am brushing out the horizontal grounds chute from the burrs to the former doser chamber. Check out the linc to my modified machine above to see what I mean.
I don't actually have much of a static issue with my modified Rocky, but I figured the conductive brush would be the next little refinment. The horizontal grounds chute in the Rocky is some sort of plastic. I haven't yet checked to see if it is conductive but I plan to. It is dull black like some conductive plastics which I have seen.
Phil
PS: I measured from the U-ground on the plug to the black plastic grounds chute with my DVM on the megohms range and found the chute to be a non-conductor.
I also found that my metalic elevator platform does not make as reliable connection to the machine or to the filter basket as I would have hoped. I will try burnishing the elevator platform and maybe some EMI gasketing below and above it.
bdbayer Said:
Sorry, I always feel a need to weigh in whenever the topic of static comes up. It is the one thing discussed in the forums that I have some expertise in. Forgive me if I get too pragmatic on the subject, but it is how I pay the bills.
The thing about static is that it needs a path to ground in order to drain off the charge. These brushes are conductive, but to what? They are designed to be used on electronic work surfaces where a ground is already in place through the wrist strap. You holding a brush and standing in rubber soled shoes is not a path to ground. For these to work properly you should either wear a static wrist strap or be touching a earth ground the whole time you are using the brush. If not you are taking on the charge and will get the old doorknob shock as soon as you touch your machine.
I would recommend you do more in grounding the griner, chute and hopper. This is the best route to static elimination on a grinder.
Now that I think about it further, one way the brush would help is if you ground it to the machine and mount it just above the chute where the ground coffee comes out. This would act as a "passive ionizer" and might just take the charge off the ground coffee. It would be hard to keep clean, but it might work when it is clean.
It looks great and it sounds like you have really thought it through.
My speculation is that if the funnel is conductive and needs to be completely grounded to the housing (sounds like you have checked for continuity from the ground lug on the AC plug (while uplugged) to the funnel). You shouldn't have to push hard on the surfaceof the funnel with your probe. If you do it might be coated with something that is causing your static.
The Rocky itself doesn't have a big static problem. I just sold my doserless and it was never a problem for me. Being this is what I do I was able to check it with a static meter and never found high levels on the ground coffee but a small amount on the chute.
My main concern is ingesting carbon fibers. I don't think these things are food grade. The static brushes that I am famailiar with are designed to work in the static field, not in direct contact with web of material. They are passive ionizers. Your link shows an actual hand brushes for electronic benches. If you buy one try just holding it about a 1/2" from the charge and see if it goes away. By theory it should remove the charge without contact.
As for the sink being nearby...mine is not, so it didn't cross my mind.
Again, you have really thought it out. That's not very common with static. Good job.
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