Dust Collectors

We often hear "after a tablesaw the second machine you should get is a good dust collector".

But not many of us spend the money on a DC until much later.  And when we finally do get one we say: "I can't believe I waited this long".  I don't think I can recall anyone who didn't have that sort of reaction when they finally broke down and bought a dust collector.

Like most people, I suffered using a ShopVac for many years.  Problem with ShopVacs are they are very noisy, their universal motors don't always last that long and they can't handle the volume of saw dust or chips produced by many woodworking machines.  But they are inexpensive and most people already have a ShopVac. In fact you probably bought one before your first woodworking machine.

I have one of those chrome "industrial" ShopVacs.  Not cheap, it was one of the more powerful ShopVacs on the market.  But until you use a true dust collector, you don't realize how inadequate even the best ShopVac is.  A dust collector will have a powerful induction motor that is relatively quiet and long lasting.  A dust collector will use a minimum 4" diameter hose instead of those narrow 1½" or 2½" shop vac hoses.  And a dust collect can suck sawdust better than the best ShopVac.
 

I went shopping for a dust collector and was ready to buy a Delta 650CFM (cubic feet per minute an measurement of airflow) unit for about $220 when I saw I could get the 1200CFM unit for about $280.  Now a 650CFM unit that is designed for single machine use, only running one woodworking machine at once, and should be adequate for any one-man home workshop.  But for the price difference, the Delta 50-850 seemed like a better deal.  Possibly overkill, but more importantly, enough power to handle any ineffeciencies I might throw at it.  By ineffeciencies I mean using long lengths of flexible hose rather than flat walled ductwork,  putting on finer bags to trap smaller particles of dust.  All things that would rob precious CFM from a dust collector.

 
 
 

A FEW THINGS TO NOTE:

  • A DC is far superior at removing large quanities of saw dust, chips and shavings compared to a ShopVac.
  • A DC is much quieter than a ShopVac.
  • It's easier to empty the bottom bag if you first line the bottom canvas bag with a garbage bag.  You loose performance but with 1200CFM don't really notice it.
  • The garbage bag doesn't have to bee too strong because the canvas bag will protect it. but it has to be strong enough so it doesn't rip when you are removing it.
  • I wouldn't put a plastic bag on without the canvas bag around it to protect even the strongest plastic bag.
  • A large elastic band (sold for $1 at Walmart and HomeDepot) makes installing the bottom bag very easy.
  • 5-micron bags are vastly superior to the 30-micron bags found on many DC units. Luckily 5-micron bags are easy to upgrade to inexpensively.
  • A remote control system really makes it easy to use a DC. I have some Remote Control information here.

 
I wanted to put a plastic garbage inside the bottom bag to help when emptying the bag. but I didn't want to loose any effiency in the DC, so to make up for any loss, I installed a taller top bag.  To get it to fit in my workshop, I had to lower the whole thing. I was pretty easy. The two vertical rods that holds the cylinder up come apart in the middle, like tent poles. I simply cut off about 6" from one end and drilled a new hole for the clip.

 
 

STILL NEED A SHOPVAC
Now after all that praise for a good dust collector, there are a few good things to say about ShopVacs.  First, they don't take up much space.  They are easy to move around, or take outside or elsewhere in the house. They can suck up the guck you would't dare let near your DC. I still use my ShopVac to cleanup the floor which often contains nails, screws, metal shavings, sand, damp (water, non-combustible) rags, leaves, etc. Things I would never want to ruin my DC with. So, although I can't imagine working without a dust collector, I certainly couldn't do without my ShopVac either.  They perform two different tasks.


DUCT WORK
Duct work can be great. The myth of static electricity causing explosions and fires has been dispelled by an MIT professor (see Fine Woodworking Jan.2002) so you can ease your mind when you use PVC, which is easier to work with and much less expensive than metal. If you insist on using metal, remember the HVAC metal ductwork found at HomeDepot and Lowes is made for pressure, not suction, and might not handle a dust collection duty. I used white Sch-40 PVC, but you can use the lighter, less expensive, greenish PVC drain pipe.

When I finally have a dedicated shop, I will re-install my PVC duct work, but let me tell you why I won't right now. My DC is on wheels and for a while I simply rolled it from machine to machine, but I soon got tired of that. So I moved it to the center of the long wall in my shop and hung some 4" Sch-40P VC ductwork on the ceiling. Then came the big garage door opener replacement fiasco and I had to take all the ductwork down. I planned to put it back up, but...... I discovered that in it's new place, the DC works well without permanent overhead duct work. It's on the center of the long wall in my shop. My Unisaw is on the right of it, my DP in front and my 8" jointer and planer on the left of it. I discovered that it's in an ideal spot to work on my machines without ductwork. The 4" flex hose reaches to the Unisaw, so I leave that connected with a blast gate at the DC. Then I have the second 4" flex hose that reaches over to the jointer/planer area. My drum sanders are on the other side of the shop, but I have to roll them over to this side when I use them anyways. Same is true with my router table and lathe. The only machine that usually stays in place and that can't reach the DC well is my CMS, which is along the opposite wall, so I simply leave my old shop vac connected to that. Even though I use 6' and 10' pieces of 4" flex hose, it works well. Probably as well as the PVC ductwork that I had up since it made the distance much longer doing up down, down up, around and around and around. It's not ideal, but I discovered that with proper placement in a small shop, if you have to move your machines anyways when you use them, then having no ductwork is just as easy or hard as having it. When I have a dedicated shop, I'll have permanent places for my machines and I'll have permanent overhead PVC duct work. But I'll have to wait a little longer.

© 2008 Mark Goodall