# Dust collection and grounding



## nightriderrv (Apr 25, 2013)

I'm going to be setting up the shop in a better way for all the woodworking toys I have now. I have to run new DC mains and drops, I would like to run pvc if possiable I have some flex line with the way it's set up now and have the copper ground running down inside of it but at times stuff will get hung on it and as we all know it will start a blockage. I'm looking for ideas and advice on the best way to solve the ground part. Also what would be a correct size for the main and drops, I have a delta DC with the top and bottom bag


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## cabinetman (Jul 5, 2007)

*This* may give you some info on static electricity.









 







.


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## Dave Paine (May 30, 2012)

Very informative link by C'man. One of the best articles I have read on the facts about statis.

Too many variables to give quick advise.
Which model DC? 

I have a 1 1/2HP Jet cannister DC. I have 4in PVC for the main duct and drops to the machines. I only have about 50 - 60 ft of straight run in total.

I would likely benefit from having 5in duct for the main run, but not in the budget.

I have improved performance recently by reducing fittings, reducing the length of flex hose, replacing short radius elbows with sweep aka long radius elbows.

You want to run the duct to be at least the size of the inlet at the dust collector. Likely 4in.

Since I only run one leg to the dust collector, I removed the Y and made a donut out of scrap plywood to reduce from my 6in at the fan inlet to my 4in duct size.

I would work hard to minimize any flex hose. It has a lot higher pressure drop than straight PVC pipe.


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## Fred Hargis (Apr 28, 2012)

The easiest solution for the grounding would be to skip it altogether.


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## toolguy1000 (Oct 4, 2012)

Fred Hargis said:


> The easiest solution for the grounding would be to skip it altogether.


+1. never been an issue with my pvc network.


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## jcal (Jul 25, 2009)

I am somewhat confused about the grounding issue. I just checked prices at the big orange box store and 26 gauge 4" metal ducting sells for about $2/foot and 4" PVC pipe also sells for about $2/foot. Why not just use metal ducting, which doesn't have the static electricity issues?


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## rrich (Jun 24, 2009)

First, Mike referenced an excellent article. In the first paragraph there is this statement, 

"Several times now, I have considered deleting this article from my website because it is not significantly applicable to a home workshop dust collection system."

makes perfect and logical sense. Yes, think about it for a home shop but just think about it.

Dust explosions are a bit different than a normal fire or explosion. We all know the fire triangle, heat, air or oxygen and combustible material or fuel. In dust explosions there is a fourth side to the triangle, combustible in sufficient concentration to support combustion. This alludes to the LEL and UEL that was discussed in the article referenced by Mike. 

There are other articles that express in scientific terms (that are over my head) that the LEL has a concentration of dust that makes breathing impossible. Also the static charge that is necessary for ignition is almost always beyond the capacity of a home dust collector.

With all of that said, and how we all want the "perfect" shop, it may be wise to take a step back and think about reality.

A home shop is basically a one man, one machine in simultaneous operation. It is possible to spend a lot of money on dust collection plumbing. The reality is that there is no dust collection that is perfect. I have worked in a shop where the dust collector was driven by a 125 HP motor and we still had to sweep up every day. (Yes one hundred twenty five horse power.)

The advice given to me by the salesman where dust collection plumbing and machines were sold was simple and direct. "You're only one man and one machine, MOVE THE DC HOSE." (Well, not exactly but this is a family forum.) I have one of these 21 foot flexible and expandable hose from Rockler and it is moved to the machine in operation. The move of the hose takes less than a minute. 

If you really want to spend your money, get something similar to a "Long Ranger" (Penn State Industries) for your DC at less than $100. You'll be able to start and stop the DC while at the machine rather than running back to the DC switch.


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## nightriderrv (Apr 25, 2013)

Thanks all
This has been all good advice, what I have is a delta two bag system with one hose that I connect to the machines as they are used. It works well and yes I do have to sweep up some, I'm going to place the tools in spots around the shop and if I don't plum all the tools in atleast have a main line ran over to the area then I could move the smaller hose to the one being used. 

So from all the reading and advice if I were to go with one sounds like the metal duct is the way to go, it will work well and it will ground soon as it's hooked in the the DC.


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## Fred Hargis (Apr 28, 2012)

I think the reason PVC is as popular as it is is cost...but not the cost of the pipe. You will easily spend as much (or more) on the fittings, and finding metal Y fittings can be a little tough. You can also mix the 2, though it looks less professional than one or the other....:laughing:


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