Another Newbie with Dust Collection Questions

[Brian O'Connell]

I am fairly new to the hobby and am just getting my shop situated. However, I am ready to ramp up the shop because we have a lot of projects to be completed - need to build a built-in for the media room and then several bookcases for the den.

I have a small shop, 11' by 19' and I expect the shop to mostly revolve around my Grizzly 0715. Because of the small size I want to limit the footprint of my dust collection system.

Here is some relevant info:
(1) I would like a fixed dust collector and don't want to wheel a portable one around as that will get in the way of my small space.
(2) Space is at a premium. Wall mount would be preferable - although it seems those are not powerful enough
(3) 220V is not a problem.
(4) I can vent to the outside
(5) Only one machine runs at a time
(6) I would really like to spend around $300 - no problem with used.

My thought was to use the outside right hand corner of my shop (Image attached). Attach the motor up high, use a thein sepeartor with a trash can mounted on a base of some sort - so that I can use the base to store my compressor, or other items. Is this a feasible approach? I looked and didn't see many dust collectors built to vent outside. Could the HF 2.0 HP model be made to work in this configuration?

Workshop Current.jpg

[Andy Fox]

Here are my thoughts, as I plan to do something similar. It's best if you can run 6" duct from the DC. I think the HF 2 HP model input is 5". I've decided to get the Grizzly 2 HP model (G1029Z2), which is on sale for $275 + $80 shipping. It also has a steel impeller, avoiding the aluminum fire hazard. I plan to simply put a Thien baffle into the existing minimal baffle, similar to what is shown in this thread. Mine will be venting inside with a 35A Wynn nano filter, but you could just put a 6" nipple in the top of the Thien baffle for the outside duct.

Edit: If there are gas or other combustion appliances in the same building as your shop, be aware that venting outside could suck carbon monoxide from those into your shop and the rest of the house/building.

[Brian O'Connell]

Here are my thoughts, as I plan to do something similar. It's best if you can run 6" duct from the DC. I think the HF 2 HP model input is 5". I've decided to get the Grizzly 2 HP model (G1029Z2), which is on sale for $275 + $80 shipping. It also has a steel impeller, avoiding the aluminum fire hazard. I plan to simply put a Thien baffle into the existing minimal baffle, similar to what is shown in this thread. Mine will be venting inside with a 35A Wynn nano filter, but you could just put a 6" nipple in the top of the Thien baffle for the outside duct.

Edit: If there are gas or other combustion appliances in the same building as your shop, be aware that venting outside could suck carbon monoxide from those into your shop and the rest of the house/building.

Interesting information. I didn't know about the differences in impeller. For the carbon monoxide question, I do have a 90% efficient gas furnace located 40 feet away in the basement that only runs when it is below 35 degrees (its a duel fuel system w/ a heat pump) so that is a concern. Could I add a fresh air inlet to the workshop that only opened when the DC was running to negate the possibility of it drawing air from the furnace?

[Ole Anderson]

It also has a steel impeller, avoiding the aluminum fire hazard.

Hmm. Oneida uses an aluminum impeller claiming "Cast aluminum alloy 356T-51 / backward inclined / non-sparking, non-ferrous as required by NFPA fire code"

[Greg Portland]

I am fairly new to the hobby and am just getting my shop situated. However, I am ready to ramp up the shop because we have a lot of projects to be completed - need to build a built-in for the media room and then several bookcases for the den.

Hi Brian. If you can vent to the outside I would consider a used motor in the 3HP-5HP range + an impeller (~15" or so). Build the blower (see and example here or on Bill Pentz's website). This is going to give you the most bang for the buck (but you'll have a big pile of wood dust outside).

[Andy Fox]

Interesting information. I didn't know about the differences in impeller. For the carbon monoxide question, I do have a 90% efficient gas furnace located 40 feet away in the basement that only runs when it is below 35 degrees (its a duel fuel system w/ a heat pump) so that is a concern. Could I add a fresh air inlet to the workshop that only opened when the DC was running to negate the possibility of it drawing air from the furnace?

From my very limited knowledge of HVAC, it might be ok if it's [edit: the furnace] direct vent style with a vent/intake through the wall instead of having a flue. I think that's definitely a question for an on-site professional though, because I don't think there's any way to tell without testing the full range of possible conditions.

Hmm. Oneida uses an aluminum impeller claiming "Cast aluminum alloy 356T-51 / backward inclined / non-sparking, non-ferrous as required by NFPA fire code"

Interesting. Bill Pentz writes:

"...unfortunately they chose to use an aluminum impeller which the National Fire Protection Association no longer recommends because these throw off 4th of July sparkler like sparks if hit by a piece of metal." (http://billpentz.com/woodworking/cyc....cfm#Impellers)

I think this is the reason Grizzly switched to a steel one.

[David Kumm]

I've seen both types of impellers- aluminum and steel both used for so long I have to think it must be a non issue given the propensity to litigate. Seems like the steel rivited blades are often sourced from Asia where labor and steel is cheaper and the cast AL made here, particularly the impellers with backwards curved or inclined blades. The big fan companies- Cincinnati, Chicago, etc seem to make both. The backward fans cast AL and the straight blade material handling impellers are welded steel and heavy. BI and BC impellers are considered clean air and steel straight are dirty air so the whole metal thing is confusing. I have used Welded steel, cast AL, rivited AL shrouded and rivited steel and the more important to me is the method of attachment. Taper lock bushings are LOTS easier to deal with than set screw locked impellers. Eliminating the filters will allow a 2 or 3 hp 14" impeller system to work really well in the small shop small machine environment. The environment outside takes the hit. Dave

[Ole Anderson]

Interesting. Bill Pentz writes:

"...unfortunately they chose to use an aluminum impeller which the National Fire Protection Association no longer recommends because these throw off 4th of July sparkler like sparks if hit by a piece of metal." (http://billpentz.com/woodworking/cyc....cfm#Impellers)

Yes, interesting indeed. I have worked aluminum for 15 years, cutting it with all sorts of saws, carbide and otherwise as well as abrasive blades and running it on the belt sander, and I don't recall ever seeing sparks. On the other hand, steel hitting steel, yes, sparks. I would like to think that Oneida knows what they are doing as they also serve the light industrial wood guys with systems up to 20 hp. And I have heard that BP and Oneida don't see eye to eye.

If you can vent to the outside I would consider a used motor in the 3HP-5HP range + an impeller (~15" or so). Build the blower (see and example here or on Bill Pentz's website). This is going to give you the most bang for the buck (but you'll have a big pile of wood dust outside).

That is a lot of suck for a small shop, particularly without a filter. 2 hp ought to be plenty (the HF DC is likely less than the claimed 2 hp). And he is looking at a separator ahead of the dust collector, so piles of sawdust outside won't be a problem.

[Brian O'Connell]

Thanks everyone for the help. I think my plan will be the following:

(1) Buy the Grizzly DC.. Essentially for the motor it seems.
(2) Mount the Grizzly high on one of my exterior walls, have a thein separator down below and the machine vent outside.
(3) Hook a 6 inch normally closed damper up to pull air in from the outside. Power that with a 220V/24V relay such that when the DC is powered the damper opens.
(4) Install a CO detector in the same room as the furnace

Going to be a bit more pricey than I had hoped with shipping and the damper.. And I haven't even started to price out the ducting yet. Almost leaves me wondering if for a one person and almost a one tool shop if I should just get the Oneida Dust Deputy and hook it up to my shop vac. However, with such a small shop that is yet another thing to get in my way.

[Jamie Buxton]

I have the impression that 90%+ efficient furnaces usually have a duct to bring combustion air in from outside, rather than burning conditioned air.

[Alan Schaffter]

I have the impression that 90%+ efficient furnaces usually have a duct to bring combustion air in from outside, rather than burning conditioned air.

I concur with that. I believe either dual or coaxial vent/combustion air pipe (PVC or metal) and a fully sealed combustion chamber are the norm. A CO detector is always a good idea and often code for new construction in many areas.

As far as damper on your make-up air source. Just use a gravity closing, free swinging (in only) damper with varmit screen on the outside. Or use the same setup with rare earth magnets or door knob type latch assembly to keep it closed. DC air flow should overcome the magnet but normal air flow (doors opening) shouldn't. If you want a positive lock use the door latch with a solenoid to unlock it- DC turns on, solenoid retracts the latch, and air flow opens the damper. When DC is off and flow decreases, damper swings shut and re-latches.

[Ole Anderson]

Almost leaves me wondering if for a one person and almost a one tool shop if I should just get the Oneida Dust Deputy and hook it up to my shop vac.

The shop vac route might work for small tools, but it will not take care of your G0713.

[Michael W. Clark]

Interesting. Bill Pentz writes:

"...unfortunately they chose to use an aluminum impeller which the National Fire Protection Association no longer recommends because these throw off 4th of July sparkler like sparks if hit by a piece of metal." (http://billpentz.com/woodworking/cyc....cfm#Impellers)

I think this is the reason Grizzly switched to a steel one.

There are different levels of spark resistance. NFPA requires a "spark resistant" fan construction when dealing with combustible dust. There are different AMCA ratings (A,B,C). Rating C is the least stringent and only requires that contact between rotating parts be minimized or reduced. Rating B requires a non-ferros wheel, usually aluminum is used. Rating A requires non ferros airstream components. Aluminum dust is very combustible, but metal:metal contact with an aluminum component does not create a spark. The concern with the spark is igniting a dust explosion or fire.

Mike

[Tom Scott]

That is a lot of suck for a small shop, particularly without a filter. 2 hp ought to be plenty (the HF DC is likely less than the claimed 2 hp). [/QUOTE]

I've tried reading through most of Bill Penz's website, and the jist of his studies has been to get enough air flow to get all the fine dust and then collect it. And you can't do that without the bigger impeller. At least that is what I get from my reading (before my eyes start glazing over and rolling into the back of my head).
I will hopefully be taking over a smaller outside shop early next year assuming we can get it cleared out sufficiently, and I have been re-thinking the dust collector issue. Right now I'm in a garage where the doors are almost always up. I have a 1hp single stage DC that I move the hose from tool to tool, but the new shop will be enclosed and the dust issue scares me a bit. I have been thinking of doing essentially the same as what Brian is suggesting. I'm still in the process of figuring out what exactly that is and which equipment I actually need, so will be interested in hearing his results or getting other input.

[Ole Anderson]

I've tried reading through most of Bill Penz's website, and the jist of his studies has been to get enough air flow to get all the fine dust and then collect it. And you can't do that without the bigger impeller. At least that is what I get from my reading (before my eyes start glazing over and rolling into the back of my head).
I will hopefully be taking over a smaller outside shop early next year assuming we can get it cleared out sufficiently, and I have been re-thinking the dust collector issue. Right now I'm in a garage where the doors are almost always up. I have a 1hp single stage DC that I move the hose from tool to tool, but the new shop will be enclosed and the dust issue scares me a bit. I have been thinking of doing essentially the same as what Brian is suggesting. I'm still in the process of figuring out what exactly that is and which equipment I actually need, so will be interested in hearing his results or getting other input.

I read every paragraph of the Pentz website info, and some of it several times and because he made a good case for the medical hazards of workshop dust, I installed an ambient air cleaner, a dust collection system with a cyclone and I use a N95 mask when I feel I may be at risk of inhaling significant dust when sanding or routing edges where my DC will not be effective and when emptying my cyclone bin and cleaning the filter. For that I thank him. That being said, Mr. Pentz, IMHO, takes some of his design criteria to a level which I feel is not necessary for my situation. It appears that his medical respiratory condition requires the most stringent design reasonably possible, and I fully respect that. The system that I now have which is based on a Oneida 2 hp cyclone system, will very adequately provide proper collection at my most critical dust generator, the table saw, with a 5" bottom and 3" top collector as he recommends, flowing approximately 800 cfm as he recommends. Will his CV system with a slightly larger impeller and bigger motor provide marginally better dust collection? Probably. Do I feel that my system for my basement shop is adequately protecting my health, absolutely. He states that an aluminum impeller is unsafe due to sparking citing NFPA criteria, which appears to be incorrect, yet he argues that PVC is a proper material for dust collection, an assumption not supported by dust collection NFPA design criteria. It is clear that Mr. Pentz has had an ax to grind with Oneida.
http://www.nordfab.com/view/assets/l...sonArticle.pdf

My engineering background does not qualify me as an expert on design of dust collection systems, however most of my professional life I have been involved in open channel and closed pipe hydraulics, so I have a good feel for duct design regarding airflow dynamics. One thing I have come to learn on Internet forums, and that is that everyone is an expert. However I quickly bow to Mr. Clark when it comes to the details of dust collection as it is apparent from his profile and his valued comments that this really is his area of expertise. Bottom line is that I could have installed a 3 or a 5 or even a 10 hp system, however the return in additional airflow was not at all proportional to the extra energy consumed, and while I don't consider myself a "green" tree hugger, I do believe that we have a responsibility to manage our resources with some degree of stewardship. So I felt it important to install a steel duct system so I could balance hydraulic pipe losses with pipe velocity most efficiently by going in one inch increments when sizing my pipes and not being constrained with the 2 inch increments when using PVC. I also felt it important to use a non-static material (steel) to avoid issues with shocks possible with plastic pipe. And frankly, to my eye, steel looks right, and no it doesn't have to be much more expensive than PVC.