Dust Collection Upgrade

[Todd Henry]

I know there are plenty of theories (and lots of science) on dust collection, but in parallel to my own research I wanted to check the wisdom of the group here. I have today a Delta AP400 Shopmaster 1hp dust collector that I have used for about 7 years with good success, although it is a one connnection at a time tool. I run through a home made separator (haven't installed the baffle yet) and overall it collects most of the dust off of the tool, but I still deal with a lot of dust that is not picked up. I am considering upgrading with Jet starting their 15% off sale next week (a Rockler gift card for Christmas has something to do with this as well).

At what point am I truly upgrading ? If I buy an equivalent 1hp Jet unit that moves 650cfm am I really upgrading or am I better off not making the purchase ? Do I need to step up to a 1.5hp unit ? of course it is better, but money is never not an object. Of course I know I can also go the Craigslist route and have no qualms about it, but if I could get a good upgrade out of the Jet sale and sell my Delta, that might be a preferred route.

Any help or advice would be appreciated.

Thanks

Todd in Atlanta

[Rod Sheridan]

Hi Todd, there are two considerations for dust collection as you're aware.

- you need enough airflow to capture the fine dust

- you need a method to keep the fine dust out of the shop air.

The first, is simple, a tablesaw needs about 500 to 600 CFM below the blade and 100 to 200 CFM above the blade. That means you need 600 to 800 CFM airflow, and an over the blade guard with dust extraction. ( I started with a tablesaw because most people have one).

Most hobby collector specs are false, I've measured some and they deleiver about 1/2 of what they claim. I have bought 2 Oneida cyclones and their claims are accurate.

Second, to prevent the fines from getting back into the air you either need to exhaust the air outside, or have a high quality cartridge filter on the dust collector.

Probably not what you wanted to hear................Regards, Rod.

[Erik Christensen]

the best source of data/info on dust collection that i know of is on bill pentz's site - google his name and you are there. to cut to the chase - is your DC for cleanliness or health?

if health, then expect to spend more $$ than just to keep things clean. as bill makes obvious - it is the invisible (dust particle size in the micron range) stuff that is most dangerous. if want clean looking shop 800 cfm might get you there but if you want healthy bill makes the point that it takes ~1500 cfm and single digit micron filters

do you really have to go that far - depends on many factors - for example - shop in exterior building and you have no current health issues re wood dust exposure you might be OK with a smaller/less capable system like you propose but if your shop is in the basement of your house that is tightly sealed 6 months of the year due to ambient temps, where your entire family is breathing 'shop air'... you might want to go to a real DC vs a chip collector

[mike mcilroy]

If you are still planning to do the one machine at a time the small step up might be enough. How short does your current system fall in your estimation? If it is very close to what you want then a small jump might be perfect. If you are only half way where you want a serious upgrade might be in order.
If you want to go stationary with ducts then thats a completely different animal.

[Phil Thien]

If the Delta is 1HP, and the Jet is 1HP, it would be a sideways move. Unless I'm missing something.

There are many variables here. Whether you plan to still move the hose from one machine to the next, whether 220 is available, the budget, etc.

FWIW, some of the cleanest shops I've been in are using a 1-1/2 to 2-HP single-stage DC, along with a good air cleaner.

[David Kumm]

I would save my money rather than make a sideways change. If your current DC has a 20" diameter bag, I would spend $75 for an oversize 1 micron filter from American Fabric, say 20" x 60" and put it on the machine. The finer weave will need the extra surface area. Then I would save up for a 2 hp machine of the same diameter and transfer the good bag to it at the later date. Dave

[James Nugnes]

I have to admit that I have been pretty surprised with what you can accomplish with 1.5HP on a one machine at a time, move the hose around basis. You have to get a canister filter, ditching the bag filter immediately. IMO, the only reason to buy a bag filter machine is so that you can choose the canister you want buy to replace the bag. So I think you stand a good chance of getting off to a good start using a 1.5HP DC as long as you maintain your one tool at a time approach.

I don't have more than a Woodstock W1049 lid on a garbage can for a separator but it is very well sealed, inlet, outlet and lid to can. Frankly I did not expect it to work at all. But it works amazingly well. Really all it is to me is a stop gap measure...a means to learn more as I work up to building something like one of Phil Thien's designs to use on my can Separator.

All of us come at this from a different perspective. In my case, my power woodworking only produces dust to fine dust. So I am going to attempt to build something biased toward collecting that kind of material......I am going to try a few things and hope to learn as I go. I actually think I catch a lucky break in only having dust to deal with....it is a difficult challenge but that translates to a fun project. If my first effort is a failure, I can rely on the Woodstock to keep me going until I can build a version of a Thien good enough to at least call it a start.

[David Kumm]

I'm not as convinced that a canister filter is the best choice with no pre separator compared to a bag. Canister takes up less room but the benefit of the really fine filtration gets lost as the pleats fill with dust and chips. The most durable canister is spun bond which doesn't filter any better than a bag correctly sized and spec'd for the purpose. Nano and HEPA type need fairly gentle air cleaning. I run both but find the bags are much easier to deal with on a direct machine and cleaning means banging them with a broom and my nano cartridges are a pain if chips get into them. Dave

[James Nugnes]

Maybe it is just me but I would never run a DC without a dust separator. So it is never a question in my case. As to whether the bag is more of an option if you don't have a separator, that is just not ever going to be a consideration for me.

[David Kumm]

A separator, other than Phil's, adds SP and reduces cfm so anything under 2 hp gets pretty marginal in capturing most of the dust from the machine. The garbage can pre separators are even worse when it comes to limiting flow. Dave

[James Nugnes]

I think it depends on what you are trying to do with the DC. If you have short hose runs of the right diameter with well sealed inlet and outlet and with lid well sealed and the other end well sealed at the tool, only trying to service one tool at a time, even things as mundane as the Woodstock 1049 lid can be "marginally" effective as part of a dust separator integrated into a DC. Build something like a Thien into the same system and you can be more than marginally successful. I am not as yet getting any dust in my DC bag even just using the Woodstock lid again very well sealed, with short runs, only servicing one tool at a time. I have to think there is some up in the canister and some very fine simply being released into the atmosphere. But turning the canister crank has yet to drive anything more than very fine dust down into the bag and looking inside the separator bin reveals a considerable amount of dust. Frankly I don't trust the Woodstock 1049 but that something so simplistic works at all suggests that something like a Thien used with exactly the same 1.5HP DC, using the same care in sealing and only servicing one machine at a time will only be more effective. That is not to say that you can accomplish with any of this stuff what you can with a commercial or industrial grade system. One of my biggest complaints specifically about many of the companies producing this home or small shop grade equipment is that they do not provide any information or a standard that users could use as a guide in trying to understand just how much is possible. Frankly I don't think we are likely to see much more from them than we see now as there are more limitations to these systems than their providers would like us to see or understand. But your choices are do nothing or do the best you can. I choose, do the best I can within the constraints of what can be accomplished with small shop or home shop equipment even if it means accomplishing far less than optimal results. in addition there are buckets of safety reasons and equipment longevity reasons for using a dust separator that go far beyond just the actual dust collection capabilities of the system as a whole. So I repeat, at least in my case, you will not ever see a DC in my shop that does not also have a separator and a canister filter and you will see me continually looking to improve the separator because it is a meaningful and interesting exercise and fun to boot. You are of course free to do whatever you wish to do in your shop.

[David Kumm]

Jim, we aren't as far apart as it sounds. You are correct that there is little reliable info out there that is helpful to a buyer. You also make a good point that the size and design of the machine and shop play a huge role in what works. I tend to think of 20" planers and 12" jointers as small so I tend towards overkill. I ran the plastic garbage can separator a million years ago too. It was way better than emptying a bag. If I had to go back to a small mobile system and the budget or space didn't allow for a 3 hp short cyclone, I'd run a 2 hp bagger with a 12" radial impeller ( radial needs a little more hp but is a little higher pressure so it handles the preseparator and flex better ) with a garbage can type pre sep, probably home made with a 5" inlet and 6" outlet to the fan. I'd have no problem with the spun bond canister, not because it filters better, but because it takes up less space than an oversize bag. I don't think that system would handle my 25" sander but most everything else ( excluding shaper ) particularly if the smaller machines had helical heads. Dave

[John Donhowe]

Let me throw in my .02-

I'd agree with Dave that a bag filter and canister can produce comparable filtration, if you consider the pore size, and the smallest dust particle that is trapped as a result. I also agree that the advantage of the canister is that it takes up less space. But let's look at how much more compact.

In addition to the ability to trap small particles, a second major factor in filter performance is the amount of resistance it makes to air flow. I think it's a valid assumption that with all other things being equal (esp. pore size), the greater the surface area of a filter, the lower its resistance to air flow. All filters will clog eventually, because even the best pre-separator cannot remove all the fine dust particles, so there will always be a dust "load" that the filter is exposed to. With time, the filter surface will cake, and the pores will clog. This increases resistance to air flow, and DC performance will suffer. A filter with greater surface area will have more "breathing room", and take longer to clog, for a given dust load.

Just for comparison, Wynn makes a spun poly canister filter, 17.5" by 23", with 100 square feet of filter area. I calculate that a fabric bag, 20" by 60" has a filter area of about 28.4 sq. ft, or less than 1.3 that of the cartridge. To get the same surface area as the cartridge, the bag would have to be more than 15 feet high.

Also, the 100 sq. ft. cartridge has the lowest filtration area of Wynn filters. Most of their cartridges designed for woodworking have 274 sq. ft of filter area, and cost little more (or less) than the poly filter. For comparable surface area, a filter bag would need to be over 40 feet high! Or, to look at it another way, with about 9 times the surface area of a conventional sized bag filter, it will take them 9 times as long to clog. Personally, I think the "bang for the buck" of a cartridge far outweighs a bag filter.

Admittedly, a pre-separator will reduce DC performance to some degree. However, if the separator can trap a lot of the small dust particles, and reduce the dust load on the filter, it will actually act to improve DC performance by keeping the filter from clogging so quickly. It all depends, of course, on the ability of the separator to trap small particles. I've never used a garbage lid (Woodstock) type separator, but from what I've read, they hardly trap any small dust, so IMO aren't worth the DC penalty. A good Thien or cyclone separator would be worth the SP cost.

[David Kumm]

John, I agree that the extra area of the cartridge is a big deal. Key is to spec material based on cfm per sq ft, just like with cartridges. I run 4 Nano cartridges on my 1400-2400 cfm system , four 20x96" bags on my Coral 7.5 hp bagger, and one 20x96" on my old 2 hp bagger. The bags don't completely expand on either bagger so I consider the sq ft to be overkill. They take up a lot of space but are much easier to clean than the Nano. Nothing wrong with a cartridge and sanding dust if you are anal about cleaning filters. I've found that mine get cleaned when I, ( or my lungs ) notice dust. Bags are self cleaning as they collapse every time you turn off the machine. Dave