Shop Vac dust collection

[Elmo Sr]

I want to say thank you to all you folks that help me, and to say I appreciate this place and the helpfulness everyone displays.

Thanks
ElmoSr

[Digitalwoodshop]

The dust moving through the machine vac hose is what causes the static charge to build up.

AL

[mcQ]

I agree with Floyd a shop vac is more prone to static buildup than a dust collector due to the smaller hose and higher velocity.
However, to be effective a bare copper ground wire needs to run through the hose where it is in contact with the moving dust particles to be effective. Wrapping the wire around the outside of the hose won't be as effective because the plastic hose
insulates the wire from contact with the dust. The instructions for any of the grounding systems say to run bare copper wire through the hose.

[DickB]

However, to be effective a bare copper ground wire needs to run through the hose where it is in contact with the moving dust particles to be effective. Wrapping the wire around the outside of the hose won't be as effective because the plastic hose
insulates the wire from contact with the dust. The instructions for any of the grounding systems say to run bare copper wire through the hose.

I don't agree. Charge builds on non-conductive duct when the moving dust contacts the duct. No significant charge collects on the dust itself, and if it did clearly most dust particles would not come in contact with a single wire inside PVC and would remain charged. A single wire, inside or out, would not effectively dissipate static from the PVC.

From airhand.com:

The following is from NFPA Code Booklet #664, section A-8-2.5.5. To obtain a copy contact: National Fire Protection Agency, Quincy, MA (617) 770-3000. It states in reference to Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities:

"Nonconductive ducts, such as PVC pipe, should not be used. A ground wire or other grounding system for PVC pipe is not acceptable."

A proper flexible hose can be used and be well grounded via the reinforcing wire:

http://www.flexaust.com/wp_super_faq...llection-hose/

[200k]

Static and dust collection has been discussed in this forum and every woodworking forum on the internet since Al Gore invented it. I have read tens of thousand of words on the subject but I just recently came across what I feel is the absolute best article addressing the subject. It covers the entire subject from a scientific point of view plus it cites specific real-world conditions. I for one am satisfied that no more discussion is needed. The link to the article entitled "Grounding PVC and Other Dust Collection Myths" is here: http://home.comcast.net/~rodec/woodw.../DC_myths.html

Subject closed. (I hope.)

200k

You'll notice I didn't declare any conclusions, did I? Make your own judgments after reading the article.

[200k]

Okay, you'll notice that just after declaring the final answer to dust collection system static I will now ask the question: Will the CarveWright machine itself benefit from extra grounding to stop static cling? I would think the ground on the power plug should be sufficient in that, at least in theory, all metal parts of the machine are connected to that ground, if for no other reason than to protect the electronics from static discharge. BUT, I still get tons of little white flecks clinging everywhere to the inside of the machine every time I cut Lexan; and that's with a serious dust collection system going. (RingNeck Blues) Will running a copper wire from a mounting screw on the RingNeck DC to a bolt in my concrete slab floor help anything?

200k

[DickB]

The Carvewright's metal parts are not grounded through the power plug. Many recommend grounding the metal parts to avoid static discharge causing electrical damage. Speaking from experience - my machine is externally grounded - I don't think it will help with "static cling".

[fwharris]

I do not think anything will/can prevent the acrylic/corain chips and dust from clinging to the inside of the machine. I've tried the dryer sheets trick of wiping down the inside of the machine and IMO it did very little.

I've also read a lot on the subject of PVC pipe for ducting in dust collection systems. Basically all said they are not suited for wood shops and no matter how you set up your grounding system they do not prevent static build up.

[mcQ]

The requirement for the wire to run inside the hose comes from the instructions from any of the ground kits sold by dust collection manufactures.
Below is the instruction sheet from Rockler, highlighted note a bare wire must run internally through the ducts and hose. Additional static suppression may
be accomplished by also wrapping a wire around the outside.

[mcQ]

This NFPA code only applies to commercial manufactures, most home shops use PVC ductwork or just directly attach a plastic hose from the dust collector to the machine.

I don't agree. Charge builds on non-conductive duct when the moving dust contacts the duct. No significant charge collects on the dust itself, and if it did clearly most dust particles would not come in contact with a single wire inside PVC and would remain charged. A single wire, inside or out, would not effectively dissipate static from the PVC.

From airhand.com:

The following is from NFPA Code Booklet #664, section A-8-2.5.5. To obtain a copy contact: National Fire Protection Agency, Quincy, MA (617) 770-3000. It states in reference to Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities:

"Nonconductive ducts, such as PVC pipe, should not be used. A ground wire or other grounding system for PVC pipe is not acceptable."

A proper flexible hose can be used and be well grounded via the reinforcing wire:

http://www.flexaust.com/wp_super_faq...llection-hose/