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Grinder Dust Collector Project-Prototype

Holescreek

Titanium
Joined
Aug 27, 2004
Location
Centerville,OH
Several members of this board (myself included) have posed questions as to what everyone else uses for grinding dust control in their home shop. I read the few threads in the archives on both boards and ended up with more questions than answers. Most of the web sites I googled cater to wood dust.

In my little home shop I have one surface grinder, a couple of snag grinders, and a small belt sander that I use only for metal. The surface grinder was my primary concern so I based all of my requirements for dust collection on it. I watched industrial Torit type units on Ebay for several months hoping that I could snag one close enough to home to pick up myself and save freight. Not having a forklift to unload a semi is one drawback, then having to either buy yet another VFD or change a motor out was another.

I refined my list of requirements to fit my wants: single phase, fine filtration, mobile, quiet, safe (from fires) and CHEAP. My wants pretty much decimated the majority of dust collectors available on the net. A friend gave me an old furnace blower so I started prototyping a dust collector around it. I figured that I'd just start trying stuff. I pulled the covers off of a Torit #64 at work to see what they did. To make a long story short, the furnace fan wasn't feasible (but it was quiet) without using a 10" duct. I was about ready to give up when I found a damaged 650CFM HF dust collector on Ebay for $30. I wasn't going to use the broken part anyway, and it was about an hour drive each way to get it. The noise that it made measured out at 95dB sitting on the floor. Putting it in the box I had left from my furnace blower attempt dropped it to 85dB and adding the insulated exhaust stack took it down to a manageable 75dB. Since this is a prototype I figure that I'll remake it out of steel on a smaller scale to fit the HF impeller later on. I used MDF for the current case. I know it can burn, but I often use MDF for impromptu welding jigs and seldom do I ever get a flame from stick welding directly against it. I've got around $50 in everything so far, and the suction is very strong. The 5 filter bags were picked up at a local flea market. I found them in the McMaster catalog as polyester filter bags rated at 25 gallons/min. I think the catalog had the mesh size at around 2-3 micron. I held a piece of filter over a butane flame and it melted but would not catch fire. I added the close weave furnace filter on top for good measure, and the whole tray slides out for maintenance. I’m sure there’s a few things I can come up with to improve on it, from what I’ve read, I could use a lot more surface area on the filter bags. I’m open to suggestions from the group.
Filter bag tray
Top Filter
Together
Stack Lining
Chute
 
that realy looks good.

about the olny improvement I can see is putting the bag house outside, It will keep the fan noise and mess outside.
 
Maybe another way to handle the dust problem could be to use coolant on the grinder then you only have mud to clean off, and no fire hazard. Uses less floor space too.
 
a customer of mine built a water filter for filtering some odd stuff he was workign with, that had silica etc in it. He had it set up so that it sprayed water over a fiberglass filter and he could either recirculate or flush the water.
 
well done that is one very good job.

the only thing is .....some surface grinders ive seen with dust extraction have it on and around the wheel like this one below ....perhaps you could hook it up as well.

E2275jsg



all the best..mark
 
Thanks for the feedback! Sadly, I don't have running water in the workshop (if I did my wife would never see me). I like the idea of adding a suction hose to the wheel guard as well. I cool my parts with a cold jet nozzle.

I saw in an obscure post where one of the members had a set-up where the air flow was pulled through a standing water bath before filtration. I don't remember there being much detail in the post though, but I'd like to know more about it.

-Mike
 
Nice job Mike. Thinking about doing the same. Oh, you don't need running water in the basement. A five gallon bucket with a small pump and hook up a return line to the bucket.
Michael
 
Looks like very nice work.

Wondering if a large 90 degree square "elbow" on the exhaust stack would further reduce the noise level.

The egg-crate/waffle foam is a wonderful idea, however noise that radiates "straight up" can still escape...if there were another foam surface directly above that might absorb some more. Might be able to accomplish the same thing with a "cone hat" type of cap lined with the foam and then exhaust air escapes 360 degrees around. Thinking somewhat like the drip cap on a fireplace's chimney.

-Matt
 
Matt,

Yes a 90 degree bend or two, baffling, plus damping helps with noise greatly: and more so with high frequencies. Related story: put a couple of street ell's between a reciprocating air compressor intake port an an air filter and appreciate a 5-6dB reduction in high frequency noise.
 








 
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