You need a non-direct pathway for return air to reduce noise transmission, so the filter stays in the closet and a "bent" return gets the air back into the shop. I believe John used a long hunk of large diameter, insulated and flexible HVAC duct. Mine is a folded return path in the i-Joist ceiling of my shop.
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The most expensive tool is the one you buy "cheaply" and often...
I think it's good to explore branches in a thread like this! Everyone benefits.
My filters are inside the closet. Much of the noise apparently comes from the cyclone exhaust and some people insulate that separately.
I exhaust into the closet then route the return air through a baffled duct I snaked through the roof trusses. The direction changes enough that I can't hear any sound through the duct. It's impossible to photograph but this is what I sketched in my shop design notebook:
Dust_collector_baffle_small.jpg
The air enter low in the closet and exits from the ceiling in the main shop. (All the ducts to the machines are in the ceiling too)
Besides the bends and baffles I sprayed the inside of the plywood duct with a rubberized coating. The closet itself has 2x6 walls built with 2x4s in a "staggered stud" sound-reduction configuration with insulation snaked between the studs. This provides no direct contact sound transmission path between the inside and outside walls. To further reduce the noise I installed double access doors on the side of the closet away from the wood shop, opening up into the maintenance bay area on the end of the shop. The air compressor line is fed through the wall to controls and dryers in the main shop then plumbed to outlets spread through the shop. I'm extremely pleased with this arrangement since it keeps the sound down for both of those beasts.
JKJ
Super helpful, thanks. Many years ago I built some homemade DIY loudspeakers and those noise reduction baffles remind me of transmission line loudspeakers. Different application, but similar concept.
I would raise the cyclone to eliminate the two 90* bends.
"Anything seems possible when you don't know what you're doing."
I honestly don't think the Oneida Dust Gorilla Pro at $500 more than the Grizzly G0442 is a better value. I'm not sure why some of you guys keep pushing me in that direction. In a side by side comparison the Griz has double the filter surface area and comparable performance characteristics but the Oneida has a smaller inlet at 7" as opposed to 8" or even 10" without the adapter collar. The only feature the Oneida has that the Grizzly doesn't is the Smart circuitry and I'm completely unconvinced that it is worth it or even necessary. It seems to me more like a gimmick that will be likely to break down after the warranty is up and cost mega $$$ to fix. At this point I'm more inclined to hold off the cyclone purchase and use the money I have and purchase some other tools on my must have before retirement in 5 to 7 years list. I can continue to move my seven year old 2hp G0548 around from machine to machine for another year and circle back for another stab at it later hoping the cyclone landscape improves or someone actually does a science based comparison of 5hp cyclones in a woodworking magazine.
Thanks for all the input. The only thing I've actually decided from this post is to go 5hp over 3hp. When and which brand now is the question. I'm still mulling it over more confused than I was before.
Based on what? Empirical data or a made in America bias? "Vastly superior" is a bit of hyperbole in my opinion. The word "superior" on its own should have been sufficient. I own a number of Grizzly stationary machines and I am quite satisfied that the quality is very good. I am much more influenced by factual data over opinion so if one doesn't offer a real critique of the differences in design, engineering, construction and real world tested performance, all the "feels" are just unconvincing. I work as a manufacturing R&D engineer so data driven multi-attribute analysis is in my wheelhouse for informed decisions and, at this point, what this post has convinced me of is that I don't have sufficient data.
Have to say I'm with you on that. Though I appreciate Oneida knowing a fair bit about what they do, some of my interactions with them while building out my own upgrade left me feeling like I was paying extra for the name more than the quality. I have some Grizzly tools that long outlasted brand names, so I'd be inclined to purchase there again.
Yes Oneida seems to be a good resource for useful know-how. I once read a note by someone who observed that the Oneida design appeared to evolve with the publication of Bill Pentz's cyclone designs. I suspect every cyclone maker out there now uses what has proven to work best with differences perhaps in the quality of components, materials, and fabrication.
And any should be better than none!
JKJ
A good 3 hp cyclone should be all you need. The Grizz G0441 is $1790 delivered and they claim 1200 cfm at 8" of static pressure (a good comparison point). Shipping weight 400 pounds, 22 amps draw at 220 volts. The equivalent Oneida would be the 3 hp V-3000 which is $1958 delivered. They claim 800 cfm at 8" of static pressure and will draw 13 amps at 220 volts. Not sure why the G0441 draws so much juice compared to the V-3000. It does have a slightly larger impeller, but there is more to impellers than diameter. Comparing the G0441 to the Dust Gorilla Pro is apples to oranges given the "smart" capabilities of the Oneida. My take (I am a 2 hp SDG owner and have a few Grizz products as well) is that I would be comfortable with the performance of either unit and would choose based on other features such as filtration and power draw as well as my preference (or not) for USA built equipment. Both are in the same ballpark cost wise.
Edit: The Wood mag 2013 shootout had an interesting chart of how well each unit actually trapped dust, which is what this all about. The Oneida with the true HEPA filter did the best by far.
Last edited by Ole Anderson; 03-06-2018 at 9:58 AM.
NOW you tell me...
Maybe I'm wrong, but it looks like the stand for the G0441 is an optional $320 expense, while the stand is included with the Oneida V series. I'm comparing the 3hp versions.
"Anything seems possible when you don't know what you're doing."
Bottom line on deciding what dust collector is the performance. Figure out how much cfm you need at the tool, factor in the duct losses and use data from someplace like Wood Magazine.
My 5 hp Oneida gives me more than enough cfm with 6" ducts. Going with larger ducts will give you more cfm but at a significant increase in cost.
I do not know about Grizzly dust collector but my Oneida was perfect with everything exactly how it should be. It was well packed and no shipping damage. I had some questions and the customer service was great.