Build your own silent dust collector.......

If you plan on Power Carving this is one area you should plan to spend some time, and money. High quality systems can be purchased from woodworking stores for less than $300.00, or you build your own from some salvaged appliance parts at a fraction of the cost. This is a lap model shown but the same principal can be used to build one capable of controlling the dust generated from your Copy Carver.  I use this model for when I am powercarving by hand once the copy is removed from the Copy Carver for detailing.  It is so nice to working with a dust collector that doesn't sound like a 747 jet reading for take off.  I often forget it is on. 

Pictured is a very efficient portable unit built from a dryer blower / motor, cotton bag, vent hose and some scrap plywood. A call to your local washing machine repairman should supply you with a source for a used blower/motor combination, the rest is easy.

If you cant find a used blower/motor you can find a new one easy enough.  Most any Heating and Cooling Supply center can provide you a high cfm blower/motor unit for less than one hundred dollars.  Look for a minimum of 300-400 cfm. 

The main advantage to this type of dust collector is virtually no noise and the inlet board rests between your legs forming a laptop work bench to work over.  This is a natural position to work in.  Most carvers tend to work from their lap instead of a bench top like most dust collectors are designed for.   Since bench top space is at a premium in most carving rooms this lap model works best.  Slide the blower / dust bag portion of the unit under a bench and inlet is free to move about the room as needed.

To make your own dust collector follow these simple steps:

Obtain a blower/motor combo unit either new or used like the one shown.   Fasten it to a piece of scrap plywood for a base.  Cut a piece of wood to adapt the blower outlet to a round disc.  Router a channel around the adapter to secure a dust bag with a large rubber O-ring.  Fasten the adapter to the blower case and caulk any seams that may allow dust to escape on the way to the collection bag.


Using an adjustable hose clamp fasten a 6 foot length, or longer, piece of flexible duct hose to the blower inlet.  Most blower cases have a flange in which to attach a hose, if not fabricate one to fit a 4" hose or larger from scrap wood and PVC pipe.


Cut a piece of wood large enough to cover your lap.  Next cut a hole large enough to accept a 3" long piece of PVC pipe the same size OD as your duct hose ID.   Epoxy the 3" length of PVC pipe into the hole with one end flush with the work surface and the other hanging down below the board at least 2".  Slid the duct hose over the PVC pipe adapter and secure with an adjustable hose clamp.  Drill two holes in the board and tie a small rope to the board, this will act as a belt keeping the inlet board in your lap as you carve.


Tape down a piece of screen to prevent your carving, tools, etc. from being sucked into the blower.  The blower wheel will shred anything that falls down the tube in an instant!!    I would rather not discuss how well it destroys what it eats, I still haven't got over the "hummingbird carving incident". Think of it as a garbage disposal in your lap. Trust me, use a screen.


Sew a cotton bag or use an old diaper bag as a dust bag.  To fasten the bag to the blower case either sew in a large rubber O-Ring or elastic into the neck of the bag.  Or you can simply slide the bag in place over the blower outlet and then put the O-ring over the bag end on the adapter.  Which ever way works best for you, the end result is the same.....dust goes in the bag!


Note: Air can only enter the bag through the inlet at a rate in which the air can leave the fabric of the bag.  A small, tightly woven material as a bag attached to the largest blower will filter no more air than a small blower with a large, medium weight material bag.  Since these blowers are high volume and low pressure you need to be concerned with how easy the bag will release filtered air.  If you cant easily breath through the fabric by holding it to your face the blower cant force air through it very easy as well.  I prefer a loose weave material for a dust bag.  It may pass a little dust at first but it will quickly seal those tiny air leaks in the fabric with sawdust seconds after you turn it on.  Once a layer of sawdust lines the inner surface of the bag it becomes a pre filter of sorts, especially after a few minutes when the dust bag becomes static charged and grabs every particle that comes near the bag wall.

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The key to this whole project....... The larger the bag you use the more surface area you have to use in filtering air quickly and the faster your air flow into the inlet will be.  Match the right bag to a blower and you will have a small tornado sucking up dust over the lap board.   I have a small 300 cfm blower running a cotton bag 4 foot long x 2 foot wide and it draws more air than another with a 750 cfm blower with a 2 foot long bag, also 2 foot wide.  Remember, most of the cfm ratings on blowers are rated as free wheeling no restriction so don't be fooled by the rating.  I have seen large blower wheels run by small motors that slow to a crawl when you choke the exhaust down with a dust bag.  Dryer blowers, like the one shown here are often over powered if anything, since the same motor is used to turn a drum full of wet clothes , so you shouldn't have a problem there.  I listed a new blower from Grainger's below that works excellent if you cant find a used dryer blower.

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Commercial dust bags used on shop style dust collectors are too constrictive to use with this type of low pressure high volume blower.  They are meant for a high pressure blower that has the strength to force air through the dense fabric.  

Sources for pre-made bags- 
Gander Mountain (36" Cotton Camping Gear Bags)
Dicks Sporting Goods (36" Cotton Camping Gear Bags)
Bass Pro Shops (36" Cotton Camping Gear Bags)
or any other sporting goods store that sells camping gear will have these bags for less than $10 ea.. They are often sold in a little black mesh draw tight bag in the camping section.  When you buy one of these bags be sure to run it thru the washing machine machine to remove the heavy starch they use in the fabric, it alone tends to restrict the material. 

Vent Hose-
Woodcraft stores sell a length of clear 4" heavy vinyl hose that works perfect for less than $20 a 10 foot length.  They have 6" as well.

New Blowers-
Grainger Supply
Website
Their Dayton Blower #4C444A is a great blower for this purpose.  Small, lightweight, silent operation, and a strong air mover.  Cost is under $100 the last I checked.

Used Blowers-
Any appliance repair shop or city dump can produce good drier blowers to serve the purpose well.  Or keep an eye open on trash day in your neighborhood.  Somebody is always putting an old drier to the curb, and 9 out of 10 times it's because of another problem, the blowers are generally fine. The older the drier the better since most of the late model stuff uses a cheaper blower setup. 

Or look for a heating and cooling repair company.  Some of the smaller gas furnaces use compact squirrel cage type blowers that work well for dust collectors.  We have one company here locally that leaves the old furnaces behind the shop as they collect them.  Once they have a large enough collection they rent a dumpster and haul them away.  Until then they let people remove parts for the asking.  I am sure there are many places like this out there.  Look and ask around.   

 

 

Mastercarver Powercarving Systems
Build your silent dust collector

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