seeking sawdust collection system design guru or pro-installed examples

[Paul Gossen]

LVL1's woodworking shop is on track to being the envy of any pro ... and pro-level tools generate pro-level hazards. 

Sawdust explosions are a real concern if you generate sawdust in a confined space and/or move it through a dust collection system (here's a simple demonstration video). 

I'm volunteering to do the work to generate design guidance for building a safe sawdust collection system in the woodworking shop, but I'm not an expert in this area. Is there anyone in the LVL1 community who has experience in this area and would be willing to work on this with me? 

I'd also like to tour some pro-installed dust collection systems with someone who knows about the safety design aspects (from what I've read so far, maintaining air velocity and dissipating static electricity buildup in the equipment are two important design considerations). If anyone knows local shops who would be open to this, can you make an introduction or set up a tour. 

I'm going to focus on this work starting tomorrow (Friday, 1/29) through Sunday, 1/31.

Good news: an effective sawdust collection system makes it easy to collect raw material for a sawdust cannon!

[Brian Wagner]

I do not know much about this but I do know you have to run a grounding wire along the hose to bleed off static electricity http://forum.vectric.com/viewtopic.php?f=2&t=19376  We had this problem at the school I work at, the usb connection on the CNC would just fail and it was due to static.

Here is another link http://www.cncsharktalk.com/viewtopic.php?f=2&t=2833

Brian

--
You received this message because you are subscribed to the Google Groups "LVL1 - Louisville's Hackerspace" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lvl1+uns...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Pat McCarthy]

I once had the job of electrical safety inspector for a wood shop in the Navy (Yup…wood… who knew)

Anyway, we had to keep all of the fixed equipment well grounded, including the dust collection system.

Had to ensure “common” ground (Not tooo hard on a ship… Big hunk of metal, floating in water….)

But for us, I would run a big copper braid from a ground pipe, to a copper bar in the room. Run grounds from everything to that bar…

Of course, this was for a light-medium duty shop (we only had 1 Molder, and he spent most of his time making decorative stuff for the ship)

 

(Off Topic)

Molders Mates, I think, no longer exist. In the past, they handled all the woodworking stuff for ships. But their main task was to make wooden molds of parts, which would be used for casting parts…

One of them, and a small (SMALL) foundry… If a part was cast, If the JFK did not have it in its vast stores, he could make it

[Paul Gossen]

Thanks for all the input, via this forum and in person, on dust collection system design and hazards. I spent the weekend following up on these leads and here's what looks to me like the consensus view of the most credible sources I could find online:

1.Sparks caused by discharge of static built up in sawdust collection systems:

a. in a small shop like ours, are not energetic enough to ignite a dust cloud (oft cited is Dr. Rod Cole's "Grounding PVC and Other Dust Collection Myths"

b. can damage the computers and electronics running the CNC machine

c. can make it painful for people to approach the woodworking tools

The ducting solution that works best for many small woodworking shops is PVC pipe. If static discharge is a problem for computers or people, shielding the outside of the pipe with grounded aluminum foil tape is a fast and cheap solution.

2. Fires started by mineral embers in the collected sawdust are a real hazard. Two ways to create those are:

a. a saw blade hits a piece of metal while cutting wood, which gets sucked into the dust collection system

b. a piece of metal is sucked into the dust collection system, and then hits the metal blower impeller.

 

Embers can smolder for hours before the fire builds enough to notice. Best practices are to use metal containers with metal lids to hold sawdust and to empty them every night.  

3. Fine sawdust in a confined woodworking shop like ours is a human health hazard (Bill Pentz's website is an oft cited resource) for both short term and long term exposures. Best solution is a well designed dust collection system. 

I am calculating what a dust collection system based on Bill Pentz's airflow criteria would look like for our space. 

Paul.  

 

 

[Daniel Johnsen]

FYI, this is on sale from Harbor Freight, has decent DIY mods and good reviews.

http://slickdeals.net/f/8473931-harbor-freight-70-gallon-2-hp-dust-collector-136-after-coupon-220-regular-170-sale-price

Daniel