Dust collection improvement by LOML

[Pete Hay]

I've been trying to maximize dust collection using my 650cfm Jet in a 20' x 30' shop. The suction side is all 4" PVC with wyes, two 45°'s for ells, and minimal flex hose. I then noticed that the discharge side factory bags were really taut. Testing collection with the top bag removed showed a huge improvement.
My lovely wife offered to increase the upper bag's area. With $3.84 worth of Wal-Mart twill and two hrs at the sewing machine, the new system looks like this. Area is about doubled. Air flow is now ~ the same as the test with no top bag.
From my experience, the most important elements of good collection are 1] mount the dust collector outside the shop, 2] minimize flex hose, and 3] maximize bag area

[Phil Thien]

Nice job!

If your wife is looking for a few extra bucks, she could sew those for members here.

Someone posted the source for the 1-micron filter material a few months ago. The stuff is fairly inexpensive, leaving some room for margin.

[Pete Hay]

Thanks, Phil. She politely declines your kind offer...
What she said took the most time was reinforcing the seams on the the 1996 original bags. Apparently the twill material unravels badly. I have to say the twill she got at Wal-Mart looks & feels nearly identical to the original.

[Robert Reece]

why do you say being outside helps collection?

[Pete Hay]

Two reasons I've noticed from my experience -- an collector outside the shop is much quieter in the work area than an inside one, hence gets turned on more often. Also an outside collector can use relatively porous bags [or maybe no bags at all] thereby minimizing restrictions.
Another advantage is that an outside collector doesn't take up valuable shop space. I've got an in-shop wall switch centrally located to power the outside receptacle. The collector is outside the shop, under a shed roof.
The 1hp 650cfm Jet connects to a TS, BS, miter saw, planer, jointer, drill press, and router table. Collection has got to be > 95%, and I don't think more air flow would collect any more except perhaps on the TS

[Rob Russell]

Remotely locating your DC is fine if you don't have to worry about sucking conditioned air out of your shop or sucking noxious fumes into the shop. In my case, my shop is in the basement. In the wintertime, I'd be sucking CO2 into the house from our boiler's exhaust and that's not something I'd want to do.

[Bill Blackburn]

To the OP - nice work !

RE: outside use
Several friends have their units outside too - and even in the winter they don't seem to notice to much issue with the so called and feared "heat loss" - considering we get to be -20 and -30F alot more than I care to think about I find it amazing. And something I may do in future.

I imagine if one was in the shop 10 hours a day they might notice some loss but in hobbiest use they say it is a total non-factor on heating bill.

[Curt Harms]

Just for grins I made some assumptions. A shop 20' by 24' with 8' ceilings contains 3840 cubic feet of air. A DC pumping 650 CFM of air out of the shop would theoretically change the air every 6 minutes. Air will not be moved evenly but still I wouldn't care for pumping that much expensively conditioned air out of the house. If I were heating a shop with wood it might be less an issue but still. Good filtration is not that expensive.

If I were in a shop that didn't have heat or air conditioning it'd be a different story. I'd still think about what Rob said about sucking carbon monoxide from any gas or oil fired devices.

[Cliff Holmes]

I'd be sucking CO2

Not to nitpick (well, ok, it's nitpicking) but I think you mean CO, not CO2. The major producer of CO2 in the shop is ... you.

[Ben Hatcher]

Cliff,
CO2 in a 5% or greater concentration can kill you in under 5 minutes. CO2 and water vapor are by far the most plentiful byproducts of combustion. The boiler exhaust pipe would probably be the most efficient source of make up air so you'd run the risk of blowing out the flame and/or pilot. Additionally, the reverse flow would likely cause less efficient combustion which would result in much more CO and soot than normal.

Since, as Curt pointed out, you'd be exchaning the air so frequently you'd probably not be able to build up the concentrations needed to kill someone. Still, like Rob said, it isn't something that you want to do.