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Dust collection system

4K views 66 replies 13 participants last post by  Redoak49 
#1 · (Edited by Moderator)
I have been debating what dust collector to get. Even though I really did not have a budget I wanted to try and get the most bang for my buck.

I did quite a bit of thinking when it came to purchasing the dust collector.

I decided to get the:

Harbor Freight 2 HP 1550 CFM Dust Collector
Adding a MERV 15 (.5 micron) canister
Adding a 12 in. Diameter Rikon impeller
Add Dust Deputy Cyclone to make it 2 stage

I was able to do all of the upgrades (filter cartridge and impeller) plus add the Dust Deputy Cyclone for less then $750

Here are some of the ones that I compared it with. (price and advertised performance)

(I used comparison before Dust Deputy added: Cost $540)
Jet $549.99
1 HP 650 CFM Dust Collector
2-Micron Canister Kit
9.5 in. Diameter impeller

(I used comparison after Dust Deputy added)
Jet $749.99
1.5 HP 1100 CFM Dust Collector with Vortex Cone
2-Micron Canister Kit
11 in. Diameter impeller

(I used comparison after Dust Deputy added)
Jet $799.99
2 HP 1200 CFM Dust Collector with Vortex Cone
2-Micron Canister Kit
12 in. Diameter impeller
 
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#2 ·
Ok so over the last couple days a had alittle time to work on my DC system. I filter and motor have been mounted (meed to add some safety straps to the motor), the cyclone is complete (went with a 60g pickle barrel instead of the blue barrel because the cyclone fit it perfect)

Please let me know if you have any suggestions that might make things better or even easier.

Really the only thing left is to connect everything and start running the piping
Floor Flooring Gas Machine Shelf
 

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#3 ·
I'm in the process of doing the same thing with a Delta 50-850, a 0.5 micron pleated filter canister, and a SDD XL with 6" inlet/outlet to match up to the 6" inlet on the fan housing. Hopefully, in the next couple days it will be finished and I can post a blog on it. Since the Delta was used and I didn't upgrade the impeller, my cost is ~$650.

What are you planning to put under the filter to catch the fines - a bag or a container?
 
#5 ·
When I initially tried things out the bag was billowing about an it was really noisy so I put a cutoff plastic barrel under the filter and it cut down the noise quite a bit.
 
#6 ·
When I initially tried things out the bag was billowing about an it was really noisy so I put a cutoff plastic barrel under the filter and it cut down the noise quite a bit.

- EarlS
Post a pic so we can see. I would also like to leave my compressor there and its alittle easer to move a plastic bag out of the way then a bucket/barrel.
 
#7 ·
Go without a bag, just blank off the filter with a wooden circle. Truth is that most of the fines that get into the filter get packed into the folds of the media, only a very small amount of them fall to the bottom.
 
#9 · (Edited by Moderator)
I would strongly recommend getting a wall mounted cyclone. Get one that was factory designed. I just don't think any of those options will even approach the performance of a tall cyclone.

Suction and separation will suffer with the other units.

Look for an old Tempest cyclone, or a used Oneida.

The 650 cfm Jet is worthless. I am a fan of Jet tools, but I got rid of that one as soon as possible.
The bigger Jet D.C. could get you by for awhile.
 
#10 ·
Go without a bag, just blank off the filter with a wooden circle. Truth is that most of the fines that get into the filter get packed into the folds of the media, only a very small amount of them fall to the bottom.

- Fred Hargis
That is correct. A properly functioning cyclone should pass very little material to the filter and, as you said, most of it ends up in the filter.

There is a downside to that approach. Closing off the bottom will add static pressure loss. I haven't measured that exact configuration but I have tested a Thein style baffle on the bottom of that collector ring, which should be very close in performance. The baffle adds 1.6" loss at 400CFM. In terms of equivalent pipe length that's 20' of 4" PVC. The solid cover could be more or less than that but is likely close.

Another thing I see here is the use of the original collector ring as a filter mount. That collector ring adds 1.2" at 400CFM compared to feeding directly into the top of the filter, like most commercial cyclones do. That's another 15' of 4" PVC.
 
#11 ·
First of all, asking questions on this forum is the best way to start. These guys were very helpful to me when I was designing and laying out my system.

A couple of suggestions.
1. Go Google Bill Pentz. This guy has a lot to say about dust collection and it's all worth the read.

2. Keep the inlet into the cyclone a straight as possible. min 5 feet if you can. You want the most efficient flow of air as it enters the cyclone. If it's too turbulent as it enters the cyclone, it can lose some cfm's as it crashes into the air flow inside of the cyclone. Imagine one spinning clockwise and the other counter-clockwise and them coming together. The cyclone will win the battle but it will lose some of it's velocity. (Again Read Bill Pentz)

3. No 45 deg sharp elbows. You want gentle sweeping curves. Every-time the air has to turn a corner it loses velocity.

With a small system, every little bit counts. Mine works so well that I can vent my exhaust directly outside to the flower bed with no dust build up on the bushes at all.
This came about not from me but from the collective wisdom on this forum.
 
#12 ·
There is a downside to that approach. Closing off the bottom will add static pressure loss.

- clagwell
I find that a little hard to understand, if you test it I would be interested in the results. The bottom will be closed off anyway, by the bag. How would eliminating the bag increase SP loss?
 
#13 ·
There is a downside to that approach. Closing off the bottom will add static pressure loss.

- clagwell

I find that a little hard to understand, if you test it I would be interested in the results. The bottom will be closed off anyway, by the bag. How would eliminating the bag increase SP loss?

- Fred Hargis
Fred, I think the issue is where the bottom is closed off. The bag allows a much larger sweep to the turn the air has to make in order to go up into the filter.

When I was testing the Thein style baffle I found that loss was very sensitive to the vertical position of the baffle. The lower the baffle the less loss. Remember that the top of the separator ring is dished downward. This leaves a sharp edge and reduced clearance when a solid bottom is added.

As I said, my actual test of the baffle showed a 1.6"@400CFM loss with the baffle mounted as low as possible, i.e., top surface of the baffle just slightly above the lower edge of the ring. The only difference between that and a solid cover is the 3/4" wide slot around 2/3 of the circumference.
 
#14 ·
If you watch the fines billowing about in the bag, it is obvious that all of the turbulence will result in some pressure loss. That makes sense for a normal DC since the only way to keep the dust in the bag is to slow the dust/air flow below the settling velocity. The settling ring (or thein baffle as you mentioned) helps slow things down and keeps the dust in the bag.

I wonder if a spiral separator ring that would direct the airflow into the filter section would work for a 2-stage with a cyclone. Consider that Clear-Vue dust collectors only have a small fines collector below the filter section on the fan outlet. All of the air goes directly into the filter section. Their approach would lead me to consider that the filter could be mounted below the transition, rather than above it, with a collection/access pot under the filter that would be used to remove the fines when the filter is cleaned off, eliminating the entire issue of the bag under the filter and the turbulence.
 
#15 ·
It still seems to me that if you see the turbulence in the bag, using a blank would reduce that…so if anything reducing SP loss. But whatever it does, I'd bet you would need some really sensitive instruments to measure the difference. But I'm just speculating…to me, this wouldn't even be worth the time to test it (if I had what was needed).
 
#16 ·
I am working on building a new shop and dust collection has been on my mind as well.
I added an equipment closet for my dust collector and air compressor. This closet has a louvered vent to the outside, and an opening into the shop. I can vent to the outside or back into the shop depending upon the weather. The opening into the shop is designed to accept 20" square furnace filters. I can also plug either or both holes to insulate against the weather or sound as the case may be.

When Mt. St. Helens erupted back in May of 1980 none of the cars could keep going. The ash was plugging their air filters. State troopers had to keep stopping and cleaning their air filters. When they spotted a guy who was able to keep on the road when nobody else could, the pulled him over and asked him how he did it?

It seams that he borrowed his wife's panty hose and put them over the air filter. It worked nicely.
All the state troopers headed off to buy panty hose for their cars.

When I get my dust collection system installed, I am going to try panty hose as a filter. They are cheep, easy to clean and I imagine that there is nothing quite like a pair of panty hose (double barrel wind sock) to dress up your shop.
 
#17 ·
As I design my new shop and dust collection system, I have looked at both the Thein Baffle and the Super Dust Deputy. I currently have a small DD and almost nothing gets past it.
I have seen YouTube videos of the new Dustopper (available at Home Depot) and it is also quite impressive (it is a Thein Baffle).

I have noticed that the Thein Baffle has a 240° slot.
What happens if the slot was a full circle?
Why 240°? Why not 270° or 200°?

I believe that the baffle is a requirement to prevent the cyclonic action from stirring up dust in the collection bin.
I am interested in the underlying reasoning behind the 240° slot.
 
#19 ·
It still seems to me that if you see the turbulence in the bag, using a blank would reduce that…so if anything reducing SP loss. But whatever it does, I d bet you would need some really sensitive instruments to measure the difference. But I m just speculating…to me, this wouldn t even be worth the time to test it (if I had what was needed).

- Fred Hargis
Fred, I have already made those measurements on a baffle on the bottom of the separator ring. It didn't take anything other than some simple instruments (pitot tube and water gauge) to show the difference. I managed to dig this out of my archives:
Rectangle Slope Font Plot Parallel


It's easy to see the difference made by the baffle.
 

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#20 ·
Was the thein baffle set up on your performance graph with or without a cyclone? I would think the place for a thein baffle would be in front of a cyclone on really heavy chip applications like a joiner or planer. The dust from sanding never seemed to come out in a thein baffle, but the cyclone seems to do a better job of it.

I look at the various DC optionsby particle size classification:

thein baffle or trash can separator - large chips
cyclone - smaller chips, visible dust
0.5 micron HEPA filter - PM10 dust (invisible that causes respiratory issues)

So for a table saw I would think a cyclone and filter would suffice, but as I mentioned, for a planer, the thein baffle or trash can separator in front of a cyclone and filter.
 
#22 ·
All I can say is wow, this dust collection stuff can get pretty complicated. Right now the only thing that I got that produces anything other then saw dust is my 13" planer.

- bbandu
I'm an engineer so I overthink everything.
 
#23 ·
Was the thein baffle set up on your performance graph with or without a cyclone? I would think the place for a thein baffle would be in front of a cyclone on really heavy chip applications like a joiner or planer….
No cyclone, just a cover plate added to the bottom of the separator with a slot in it. The slot was like that used in the bottom of a Thein baffle. It's not the complete Phil Thein design, just the bottom piece. TheRock is correct: "I believe that the baffle is a requirement to prevent the cyclonic action from stirring up dust in the collection bin."

I would not use both a Thein baffle and cyclone at the same time. The static pressure loss of that combination would be unacceptable to me. I suppose if your CFM requirements were minimal and the cyclone collection bin too small an additional separator could be useful. I would be more likely to use a low loss straight through drop box rather than a trash can or Thein separator though.
 
#24 ·
I guess our disconnect is that I don't see the Thein baffle being the same as just a blank. The difference between a blank and a small bag just can't be that much…but I'll debate no more, the OP has enough info to do what he needs to.
 
#25 ·
I guess our disconnect is that I don t see the Thein baffle being the same as just a blank. The difference between a blank and a small bag just can t be that much…but I ll debate no more, the OP has enough info to do what he needs to.

- Fred Hargis
I really thank everyone for all of the debating about which is better but to tell you the truth most of it is way over my head.
 
#26 ·
I guess our disconnect is that I don t see the Thein baffle being the same as just a blank. The difference between a blank and a small bag just can t be that much…but I ll debate no more, the OP has enough info to do what he needs to.

- Fred Hargis
fwiw:
Handwriting Rectangle Font Line Slope
 

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