woodust igniting

[herb]

Hi,

I read an article in magazine that talked about would dust igniting. I understand that dust extractor tubes should be grounded for this reason. Anybody have knowledge/experience about what should be done about this?

Herb

 

[Thomas Stegall]

Don't know, but I do know from the experience of a fellow club member that using a torch to highlight the growth rings as taught by Nick Cook, is not a good thing to do while your dust collector is running!

 

[hockenbery]

Dust is highly flammable.

No metal shovels in a grain bins.

A spark can ignite wood dust, grain dust, coal dust and it can spread quickly enough to make an explosion.

You can ground metal pipes and run a copper ground wire through plastic pipe.

What the actual risk is will vary greatly.
Al

 

[Jon Minerich]

I used to manage some large, store fixture plants. All dust collection systems were grounded and had one-way trap doors to prevent dust ignition and/or flashback. You may have read about grain elevator explosions. The dust, when mixed with the right proportion of air, is highly combustible. The same holds true with sawdust. I was fortunate not to have any serious fires, just one small one and all the fire suppressions systems worked as advertised. Still it sounded like a small stick of dynamite going off, followed with a roar like a space shuttle launch. Not something I would want anyone to experience.

All this said, with a bit common sense things should not be so hazardous in a small workshop - you won't be generating the volumes of dust and using high pressure ventilation systems like a large plant. Keep things relatively clean and minimize open flames and you should be OK.

 

[MichaelMouse]

This is a subject which ignites participants rather than dust whenever it's brought up. Never has been a sawdust explosion in any shop as near as anyone can determine. Good writeup in FWW. Which is not surprising, given the conditions required in the way of particle size, dispersion and ignition.

You can ground a metal pipe to protect against building static. Grain elevators do, and they still have problems from other sources. You cannot ground a non-conductive plastic pipe, so regard that as non-productive use of copper.

Bottom line, if you're the kind who armors up to turn, you might feel better taking "preventive" measures. No harm there. Also no harm in using metal or plastics without hanging wires.

 

[robo hippy]

Kids and their toys........

http://www.youtube.com/watch?v=IvPL7KC1DEA

robo hippy

 

[Bill Boehme]

This is a subject which ignites participants rather than dust whenever it's brought up. Never has been a sawdust explosion in any shop as near as anyone can determine. Good writeup in FWW. Which is not surprising, given the conditions required in the way of particle size, dispersion and ignition.

You can ground a metal pipe to protect against building static. Grain elevators do, and they still have problems from other sources. You cannot ground a non-conductive plastic pipe, so regard that as non-productive use of copper.

Bottom line, if you're the kind who armors up to turn, you might feel better taking "preventive" measures. No harm there. Also no harm in using metal or plastics without hanging wires.

Thanks, you saved me the trouble of posting essentially the same comments.

I was in Rockler's and saw a "grounding kit" for plastic ducts. The reason that they sold it was that customers demanded it and not because it it works, because it doesn't.

 

[Rob Wallace]

This discussion has been going on for decades.....

.... and probably will continue to go on as long as myths continue to be propagated....

Have a read of Dr. Rod Cole's detailed summary of the situation regarding insulated/plastic vs. metal ducting, grounding requirements, "grounding" plastic pipe, etc. and the probabilities of spark-induced ignition in a wood dust collection system. Published around 2000/2001 or so:

http://home.comcast.net/~rodec/woodworking/articles/DC_myths.html

It's a long, yet detailed read. Grab a beer or two and have at it.

Cheers,

Rob

 

[john lucas]

I had a fireman friend over to check out my shop for fire hazards and I asked him about dust explosions. He said they demonstrated that at the academy. The dust is far thicker in the air than we would ever have in a woodshop. Maybe if the dust collector bag busts open and fill the room but even then it's pretty marginal.
Far more likely is a fire created by dust in electrical boxes, oily rags left in a bundle, or fumes from things like lacquer thinner, or other cleaning chemicals. f
He said use common sense and ground the dust collector. Clean the shop regularly and keep all flammables in a safe area, use them with plenty of ventilation and spread oily rags out flat to dry on the concrete floor before tossing them.

 

[nicktodd]

Wood Magazine Article

There was an in-depth article in Wood magazine that quoted one of their experts stating you would have to have enough dust in the air that would obscure your view of something three feet away before dust would ignite.

As John stated, I am more concerned with dust accumulating on the floor or outlets.

 

[John King]

Everything You Ever Wanted to Know About Dust Collection

Checkout following web site: http://billpentz.com/woodworking/cyclone/index.cfm. See section on Ducting, Static Electricity. - John

 

[herb]

dust ignition

Hi,

Thanks for all of your good info, I knew I could count on you.

Herb

 

[Michael Powers]

Checkout following web site: http://billpentz.com/woodworking/cyclone/index.cfm. See section on Ducting, Static Electricity. - John

Speaking of Bill Pentz.. I own a Clearvue Cyclone and absolutely love the thing! The original creater of the Clearvue sold the company about a year ago and the new owner moved the operation to the Pacific Northwest (lucky me!). It is really a kind of "build it yourself" kind of machine, but I love those kinds of tools. Anyway, thought I would throw in a plug for anyone looking to upgrade to a cyclone dust collector. One of the best additions I ever put in my shop (short of my lathe of course..).