Dust collection question for the braintrust

[bob_reda]

I am in the process of taking apart a 20 foot section of my 6" metal dust collection piping to my cyclone. It was clogged to my cnc machine. I suspect that the wire running inside of the plastic sections, ie the drop and connection point caused the problem collecting the larger particles or strands and starting the clog. I was wanting to reduce the size to 4" s&d plastic piping for more suction power at the cnc. Instead of running the grounding wire inside I was thinking on running it on the outside of the pipe, using pop-rivets to hold it on the pipe. I was thinking of running the rivets every 6 inches or so, having the tip of the rivet exposed inside the pipe to act as a receiver for any static electric and being connected via the wire on the outside back to the cyclone. I hope I am making some sense and for those with more electrical knowledge than me, wondering if this would work or if not why not?
TIA
Bob

[jTr]

Downsizing is only going to reduce the flow.
Don't waste a nickel on smaller stuff, especially PVC.
Keep every bit of that big, beautiful, 6" metal pipe in place. Replace any PVC fittings or straight runs with metal components as time/budget allow. If your PVC sections are fairly short, you could consider that chips will get discharged as they travel to the next section of metal, provided you've got good continuity all the way back to the cyclone, regardless of the new vs old method of running the wire as you've described.
In an ideal situation, that inner ground wire should only be present in the 6-10' section of flex from dust pick-up shoe to the metal ducting above.

I learned long ago to make a simple spider-web pattern of the copper wire at the mouth of your dust shoe. This is where the bird's nest will form, making any clog super easy to clean. Been running it this way for almost 8 years, absolutely no clogs anywhere but there.

This can go real deep into a debate over PVC vs. Metal for dust collection. Not my intent, but I must say, due to all the issues relating to static sensitivity with the cnc, metal wins the debate here. Your best bet is to go 100% metal duct for the CNC, ASAP.

Final Note: if you have no choice but to keep utilizing some PVC for the short term, I'd recommend carefully re-running your internal ground wire in a straight, taut line. Orient all pieces so that ground wire is at the top of the inside of the duct to reduce likelihood of debris settling and catching on it. It's been repeated here numerous times over the years; the ground wire must be inside to properly discharge dust particles.

= Again, metal duct rules here. Sucks to pay, but once and done is a darn good investment when time and money are critical...

Jeff

[bob_reda]

Jeff,
Already have the metal duct, looks like it will be going back up. Never thought of the web at beginning. Thanks, will give it a try.
Bob

[chiloquinruss]

I have 4 inch PVC (12 years now) and don't have issues with clogging. I also have bare wire running through all of it, except at the gates of course. Russ

http://www.talkshopbot.com/forum/attachment.php?attachmentid=33832&stc=1 http://www.talkshopbot.com/forum/attachment.php?attachmentid=33833&stc=1

[dlcw]

I've been running 4" flex and metal for my CNC for years. I do get clogging when cutting some types of plywood, which is 98% of what I cut on my machine. When carving solid woods, I've never had a clogging problem. It's only plywood when the cutting process creates long stringy pieces that get sucked into the pipe eventually building up in areas where the pipe makes a turn. Before I had a cyclone DC for my CNC, I used a China Freight DC that always clogged up at the intake to the motor housing. Easy to clean out.

I'm with everyone else here, KEEP YOUR BIG METAL PIPE! Nothing better for dust collection.

[bob_reda]

Most of the strings I get is from poplar or the softer hardwoods. Russ you system looks really nice, you want to come and do mine?? :) :0

[JimmyD]

In an ideal situation, that inner ground wire should only be present in the 6-10' section of flex from dust pick-up shoe to the metal ducting above.

I respectfully disagree. The bare internal grounding wire needs to run the full length from inlet to outlet into the collector, and it needs to be well grounded.

[jTr]

https://www.youtube.com/watch?v=zKzjhp-yDkE&feature=youtu.be

[chiloquinruss]

Bob, gee I'd love to but you see I have to stay in my shop! ;) The secret to good dust collection is the amount of CFM for your DC unit. I have the Woodmaster and its awesome. Russ

https://www.woodmastertools.com/shop/accessories/drum-sander-parts-accessories/5hp-big-max-dust-collector/

[tlempicke]

I just moved to a new shop and treated myself to an Ivac automatic blast gate setup. Works well and totally automates the dust collection operation.

Ivac sells a really nice grounding kit. Easy to install and looks good. click https://www.ivacswitch.com/ivac-grounding-kit/