Dust collector bag replacement

[jack]

Went to the IWF. Pretty impressive. Bought a 1 mil dust collector bag for my 2HP 1200CFM dust collector. Its twice as tall as the original one, about 5-6 feet and 24 inch vs

1. Didnt have a strap so I used bungie corg to hold it on. Turned it on and it just laid there in a pile. Fluffed it up a little, still no inflation. Finally ran a cord over a rafter and hoisted it up. Looks impressive and there is almost no internal pressure on the bag. The old one was sooo tight and had little dust leaks. 80 bucks, should have done this sooner. Jack

[Tom]

Jack wrote:>Bought a 1 mil dust collector bag for my 2HP 1200CFM dust collector.

Shouldn't there be internal pressure on the bag? Tom Work at your leisure!

[George]

Constant confusion over the two methods of capture. If you think in terms of mesh alone, like sand through a sieve, you understand one method of trapping larger and then small particles. If you think of sand in a sluice, where intermediate barriers cause turbulence and settling, you have another. The felt bags offer so many opportunities for the trapping of particles and the exit of air that they are not turgid until fairly well loaded, and don't unload as fully as a thin bag when merely shaken.

[DarylRos]

Something is wrong. The bag should indeed inflate. You are pumping probably 450 cfm into it after all (I say that as I assume you are using 4" hose. Close to doouble that for 6"--you don't really get 1200 moved without 7or 8" piping. Anyway, you said you were using a bungee cord. If you don't have a strap clamp that big, get a couple of smaller clamps, and piggy back them together (it works with those quick adjuist clamps places like Woodworkers Cupply sells), and tighten in around the new bag. If it does not inflate after that, then check the whole collector. The bigger bag gives you more filter area, it does not reduce the pressure out, not on a collector as big as yours.

[George]

Do not do this. It's force/unit of area and weight that count, and resistance to flow. Daryl is in error.

[Gary]

Greater minds than mine know more about this, but it seems that higher quality 1 micron or smaller felt bags have less resistance than the 30 micron bags, hence less inflation tightness. Try blowing air INTO each with your breath and you'll notice the difference. I seems that although the holes are smaller, there's a heck of a lot more of them.

How's that for a non-technical explanation? Gary

[Steve Knight]

O Fluffed it up a little, still no

that won't last long once you start using it though.

[Steve Knight]

no that's the way it works till you get a dust cake in it. then it will inflate till it is tight. right now the airflow is that good.

[Pounds on Wood]

Did you have a blast gate open? No flow, no blow.

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[jack]

I think the felt bag is just that much less resistant to the air flow, plus more than double the surface area. I can tell the suction is much greater also. Per Steve I cranked up the drum sander and the bandsaw to see how well they did. Much better. I think a wide belt would be a better test, maybe I should get one. Oh well time clogs all Jack