What to do with my 3hp twin bag dust collector?

[Silas Smith]

What is the best option to make my dust collection better? I know the felt bags don't do a great job of capturing the fine dust and the twin bags take up a lot of floor space. I would like to build a cyclone, but I don't know how much that would cost if I already have some parts that I salvage from my current setup.

What would be the cheapest way to improve my dust collection and use less overall floor space? BTW, venting to the outside isn't a great option. Here are the specs of my current system:

General Intl. Powerful 3 HP, TEFC permanently-lubricated motor with a continuous-duty rating designed for industrial applications. Precision, spin-balanced aluminum impeller for smooth operation, less noise.


2 washable extra-fine 2-micron filter bags
Heavy-duty collection bags of extra-thick, clear recyclable plastic
Quick-release bag clamps w/metal straps
Heavy-duty construction w/4 swivel casters for stable mobility
Steel collector body mounted on 3 heavy-duty rods
Safety switch w/key
12" dia. blower wheel
6" inlet with three 4" inlet ports
85 to 95 dBA
CSA Approved
220V, 3 HP, 1 Phase.
2,280 Air Volume CFM.
5-9/16" Static Pressure in Water.
83 gal. Collection Bag Capacity.
Tool size 60"L x 32-5/8"W x 76"H.
Tool weight 165 lbs.

[Jamie Buxton]

If your primary objective is to use less floor space, and you'd like to control the budget, you can just remove one bag pair. That's real low-budget. The trade-off is that you'll have to empty the single collection bag twice as often.

[Silas Smith]

If your primary objective is to use less floor space, and you'd like to control the budget, you can just remove one bag pair. That's real low-budget. The trade-off is that you'll have to empty the single collection bag twice as often.

Wouldn't effectively half the filtration area of my exhaust and push more fines through the upper felt bag?

[Jamie Buxton]

Wouldn't effectively half the filtration area of my exhaust and push more fines through the upper felt bag?

Think about it this way... All filters are rated as to what percentage they stop of particles of some given size. For instance, a filter might catch 99% of 10 micron particles, 95% of 5 micron particles, and 90% of 1 micron particles. That is, halving the surface area of your filter doesn't change what proportion of the fine particles get through. What halving the filter area might do is increase the pressure on the inside of the bag, so you get a little less air flow through your system.

If you know the filtering characteristics of your filter bags, so you have something to compare, you might shop for better bags -- ones that filter a larger percentage of those fine particles. You can put a new bag on your system quite painlessly. American Filter Fabric is one supplier of bag upgrades.

[David Kumm]

All bags are rated for cfm per sq ft. Usually 40-55. You want bigger bags, not smaller- or taller. Halving the bags may or may not reduce the filtration efficiency but will reduce the cfm which will allow more dust to escape the machine which is the worst deal of all. If you are dealing with sanding dust you need to spend 150-200 on a couple of good bags, or at least buy them one at a time. Dave

[Andy Pratt]

The best thing to do with it would be to sell it to a guy who has never used a cyclone and buy a cyclone, or use the re-useable parts to make a cyclone. I feel like anyone who uses the two bag system ends up either hating their dust collector or not getting the full benefit out of it. People who have a cyclone are used to not having to think much about their dust collector, as a comparison.

Since it sounds like you already have a good impeller/motor, maybe you can get a machine shop to fab up a cyclone cone with ports for you and cannibalize the motor and impeller for the cyclone. I imagine you are looking at $400-800 and a bunch of time investment for that as opposed to $1500-$2000 for an equivalent cyclone bought new. If you can sell your existing system for $500-700 I would think at that point it is better to do that and buy the cyclone outright.

The cyclone is simply a better design, and I don't see double bag dcs staying around too much longer as cyclones become more widespread/smaller/less expensive. If you are about to put a bunch of time into you dc system, put it toward getting a cyclone one way or the other.

[David Kumm]

Putting a cyclone in front of a 12" impeller will cost 2-4" of SP and make the system marginal for cfm. Most cyclones run 14" impellers with a 3 hp motor to compensate. There are many non cyclone commercial units out there. I like cyclones but their purpose is help keep the filters cleaner longer. If you reinvent the wheel you should start from the ground up. Or just put the right bags on what you have until you can afford the final system. Dave

[Cary Falk]

I was in you boat a couple of years ago. I figured I could sell my double bagger and buy a cyclone outright for about the same amount out of pocket money I could build a cyclone out of the double bagger. The impeller would be smaller if I used the one from the double bagger. I bought a 3hp Grizzly and couldn't be happier.

[Jamie Buxton]

If you're leaning toward a cyclone, and want a smaller footprint than your bagger, shop carefully. For instance, the Grizzly 3 hp cyclone has a footprint larger than your present unit.

[Silas Smith]

Does the penn state cyclone get decent reviews?

[Jamie Buxton]

Does the penn state cyclone get decent reviews?

You can search SMC. Go to the page headed "Forum: General Woodworking and Power Tools". At the right, there's a Search box. Enter whatever search term you want. "Tempest" brings lots of threads about Penn State's cyclones. With other search terms, you can find about a zillion threads about various cyclones. Cyclones are also often discussed in the Shop forum.