I'd choose cancer, my wife would treat me better.
Contributor
I'd choose cancer, my wife would treat me better.
Contributor
I'm blown away (pun intended) by the gorilla-sized systems described here. I'm in a 20 x 22' shop (garage) with a 1.5 HP Delta 50-850 (remember those? they're supposed to be 1100 cfm, I think), Wynn filter, and a Super Dust Deputy. The DC impeller inlet and outlet are 6", as are the SDD top and bottom outlets. But the SDD inlet from the room system is 5". I immediately step this down to 4" and run 4" PVC all over the room. I have four blast gates near the ceiling, each with its 4" flex hose swinging down to whichever 3 or 4 machines are in use at the time: some 4" ports {Delta Unisaw, router table underneath, 6" jointer, 12" planer} and some 2-1/2" ports {tiny 10" band saw (love it!), router table fence, and even the drill press}. The flex hoses are long enough to do multiple duty. Yes, I take care to keep only one blast gate open at a time.
But it's all 4" ducting. The suction on that thing can pick up a chisel and send it across the ceiling, through the PVC, around the 45Ί bends, and smack dab into the bucket below the SDD. It can suck up a foot-deep pile of hand-plane shavings on the bench in seconds and send it 25 feet across the room.
Why 7", I wonder?
Last edited by Bob Jones 5443; 01-10-2020 at 1:39 AM.
Member
For a 5hp Cyclone like a Clearvue or Oneida, pulling aroj d 1000cfm, a 7" duct is about the optimal size to reduce losses but maintain high enough air velocity to keep particles and chips suspended for a typical shop setup.Unless your 1.5hp collector is something special I'd estimate you would be getting somewhere between maybe 150-250cfm at your tools with your setup. I tested a standard 2hp dust collector with a pleated cartridge filter and only 3 feet of 4" flex and measured about 250-300cfm from memory using a hot wire anemometer. With any more ducting it would obviously have been far worse. The unit was specified at 1200cfm lol. If your setup is working for you then great. Everyone needs to find a compromise that they are happy with. Unfotunately it's an exponential curve (literally) when it comes to dust collection, with increases in performance costing increasingly more (in both $$ and horsepower). I do think that it's worth investing in though - particularly if you can afford it financially. Better to stretch here than for an expensive table saw etc IMO.Cheers, DomOriginally Posted by Bob Jones 5443
I was quite pleasantly surprised when I did some flow measurements of my system, 2 hp Oneida Super Dust Gorilla with 7" horizontal mains. Using an anemometer, which is not quite as accurate as a hot wire version for sure, likely overstating numbers somewhat. But it says I am pulling 1227 cfm at the bottom of my 6" vertical drop just upstream of the cyclone, indicated velocity 6,250 fpm. At the end of my slinky 4" hose just before my router table I am indicating 6,160 fpm or 570 cfm.
If you want fan curves and filter efficiency for dust collectors that were generated at least from a common setup, check out the reviews done at Wood Magazine in 2013. https://www.oneida-air.com/amfile/fi...oduct_id/1902/
Here is a video as to their test technique used on bag collectors in 2016. https://www.youtube.com/watch?v=48CMPfq6PUg
NOW you tell me...
Contributor
Actually, a 5hp cyclone can pull a lot more than 1000 cfm on a 7" duct.
With mine I get the following
8" Duct 1 660 cfm
6" Duct 1 350 cfm
4" Duct 650 cfm
Member
Thanks Ole. That's a good find.
Beranek's Law:
It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.
Contributor
Anemometer or no anemometer, I get a voracious suck at the end of each of my dropdowns, even when I forget to close one of the blast gates not in use. Love the 4 system.
Contributor
Post # 1
I'me with you on this one Bob, and I think, Maureen, you'll have plenty of power and suction to keep the dust to a real minimum.
I have a Jet 1.5HP unit, converted to a two stage and the residual dust from most operations is so minimal that I don't bother moving my motorcycle out of my garage.
My setup is a 5" diameter run along the 9' high celing, about 40' in length, with three vertical drops that go down to 4" blast gates, with about 15' 4" flex hose going down to the appropriate tool. I only run with one blast gate open.
This sits about 18' away from all my woodworking tools over in the other bay. I don't even bother putting a cover on it.
Contributor
To some extent your comparing apples to oranges. There's a hit to performance when going through the cyclone on a two stage DC that a single stage like yours does not have. So a single stage generally needs less HP, I think around 20-30% less. You're also going to get more speed as you reduce the size, while giving up some cfm. Larger ducts just have less resistance, and allow more to go through them. Nor is it a linear step down. The area difference between 5" and 4" is 19.6" vs 12.5" and stepping up to 6" is even better. As the resistance steps up, the motor does less and less work. Depending on a lot of factors, you might get better performance with 5" duct, instead of 4", and if you used rigid instead of flex, but if what' you've got works, that's enough.
I haven't done the math, but I think 5-6" is probably the top of the range for the impeller and motor you've got on your dust collector. If you look around you'll notice that they usually don't go to 7-8" until around 3-5 HP.
Further I'll agree with you that what you've got is sufficient. I've been very pleased with my 2HP cyclone, though I don't think it would pick up a chisel, it handles everything else. More is always better, but often not for your pocket book!
Member
I am still working on my dust collection. I have the 2HP HF blower/motor mounted on top of a super dust deputy and exhausting outside. I have 5 inch snap lock running to my table saw where it reduces to 4 inch to hook up to the saw. I measured about 400 CFM inside the flex hose inside the saw. I am pretty sure it would increase significantly with more cross sectional area at the saw but it also has a shroud around the blade that helps it collect dust (it is a Saw Stop PCS). I have minimal dust in the saw cabinet so it seems to work. I need above the table collection but it won't be the next thing I do.
I decided to try putting a long flex hose - 4 inch - and running that to my planner and jointer temporarily until I put in more hard duct. It seems to work very well. I get nearly complete collection of chips at the planner (10 inch Ryobi AP-10). I should get my floor sweep attachment from Rockler tomorrow to hook to this 4 inch flex line. I have plenty of suction to clear the floor easily.
I also plan to add a Dylos meter so I know what dust level I have. They are not terribly expensive. It seems like I may be able to gain about as much dust reduction by fine tuning my system (collection at the tool) as I might by brute forcing up to a 5 hp collector. But that is a guess - and thus the need for measurements. If the meter says my dust level is high, I can also add ambient air cleaner or a mask.
I think Matthias Wandel has interesting thoughts on dust collection. They are very different from Bill Pentz's. Matthias has taken measurements using his Dylos on his setup and other peoples.
Bill Pentz also uses special filters on his HVAC system in his house due to his high sensitivities. I am not that sensitive. But I want to do a reasonable job and I am a bit frustrated that there is a lot of talk about dust collection and a lot of opinions but not much real data. But I am on the same track at the moment and will be until I get a meter.
Last edited by Jim Dwight; 01-10-2020 at 8:14 PM.
Contributor
Use of the fan anemometer will greatly over estimate air flow. Even with hot wire anemometer, you need to carefully measure across the pipe at several locations in the middle of a long test pipe away from the end. That is how I did my measurements. Unfortunately, it is not easy to make a good estimate of air flow.
Please define greatly. 5%, 50%? Have you done or seen actual bench comparisons in order to quantify "greatly"?
NOW you tell me...
Member
That's very good performance. I have a clearvue with the larger 16" impeller. I get just under 1000cfm at my table saw using all 6" duct with about 1 foot of flex. I think I may have been sold the 16" impeller with the regular impeller housing from the CV1800 - this may be an issue and I may get better performance if I buy the CV Max housing and swap it over - just never want to spend the $600 for the housing and the effort to change for a possible improvement.Cheers, Dom
Contributor
Nicest piece of machinery i have seen in a woodworking shop!
Post # 1
This sits about 18' away from all my woodworking tools over in the other bay. I don't even bother putting a cover on it.
Contributor
To answer the question about fan anemometers, I started a new thread.
Posting Permissions
Reply With Quote
