Dust Collecting Question(s)

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Forum topic by scoutii posted 03-07-2016 02:02 PM 610 views 0 times favorited 6 replies Add to Favorites Watch
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2 posts in 778 days

03-07-2016 02:02 PM

Hey all – about 7 months ago i picked up a dust collector from harbor freight. the first thing i did was swap out the 5 micron back for a 1 micron bag. it worked super well. this thing was so powerful that i literally could not get the hose near anything or it would get sucked into the fan. no joke, i got within 6 inches of a 2×4 and it sucked it into the hose.

question 1: so 7 monthly later the suction has really dropped. i can almost put the hose directly over a pair of gloves and they won’t suck them up. i recently took the bag outside and shook out. it really didn’t improve the suction so i vacuumed out the inside with my shop vac. it still didn’t really improve the suction. the filter bag i bought was the cheapest one i could find from sears. is it possible that they eventually go bad to the point that you can’t re-use them?

question 2: the dust collector came with a Y separator so i connected an adapter so i could run a dust extractor hose (35mm) to exhaust pipe of my miter saw. there is almost no suction coming from the hose even if i block the other hose coming from the Y. based on restricting the pipe shouldn’t the suction increase?

thanks, todd

6 replies so far

View Fred Hargis's profile

Fred Hargis

4954 posts in 2460 days

#1 posted 03-07-2016 02:46 PM

The filter bag could be caked up, good ones are made with the felt “singed” on the inside to keep the duct cake from becoming excessive (it’s actually part of the filtering system) where the cake builds so much and then starts falling into the bag. You could turn the bag inside out (outside, on a windy day) and vac the surface. Try it again and see what happens. You really didn’t provide many details about how you’re DC is hooked up. Is it possible there’s a clog in the duct? Also, you shouldn’t be surprised when you see air flow fall off once you choke the thing down….read some of the DC threads here and you will quickly pick up on “the DC is a high flow, low static pressure machine”, as opposed to a shop vac which is low flow, high static pressure machine. Choking a DC down (is that what happened with the reduced flow) just doesn’t get it. As impressed as you are with the air flow you had, it really isn’t all that great compared to what you really need for excellent DC….but that’s another discussion. Anyway, somewhere something changed to cause the reduced air flow, it’s just a matter of tracking it down. Oops. forgot….good bags don’t generally “wear” out, though I suppose cheap ones could get fine dust jammed in the pores to the point of not being usable; but that’s speculation on my part. As a test, you could put the OEM bag back on and see if the air flow increases.

-- Our village hasn't lost it's idiot, he was elected to congress.

View WhyMe's profile


1008 posts in 1528 days

#2 posted 03-07-2016 02:50 PM

Run the DC without the filter bag installed and check the suction? If suction is still bad then you have a clog in a hose or inside somewhere. Also check that the impeller has not come loose from the motor.

View scoutii's profile


2 posts in 778 days

#3 posted 03-07-2016 03:38 PM

Thank you very much, guys. No, there shouldn’t be a clog in the hose but I will double check tonight. All hoses are 4”. The setup is as follows. There is a Y connected directly to the impeller and there is about 4 feet of hose on one side that connects to another Y. 6 feet of 4” hose continues to my miter saw (propped up behind the saw). The other half of the Y connects to a 1 1/4” dust hose that connects to the exhaust pipe of the miter saw. The other half of the Y at the motor just connects to a 10’ section of hose that has a shut off valve on one end.
Would having any dust in the lower collection bag matter? There isn’t much, maybe 7 inches or so.

View Woodcut1's profile


34 posts in 790 days

#4 posted 03-07-2016 05:59 PM

Seems you have a lot of hose hooked to the collector. I am assuming it is a smaller unit of three quarter HP or so. At any rate I would start by disconnecting the house and see what you have at the collector input. If it is still good at the collector input it is the hose. If it is the same disconnect the filter and try again. If the suction is not back to normal then it Is probably in the collector . If there is no internal clog in the tool and after checking the tool to insure it is running freely you might want to be talking to the manufacturer of the tool.

View JollyGreen67's profile


1663 posts in 2730 days

#5 posted 03-07-2016 11:37 PM

I have a Rockler 1micron dust bag attached to my 1hp HF DC. To clean the bag, I turn it inside out, hang upside down and spray with my hose -GENTLY ! – to remove the dust. Do not scrape it with anything, hang it up in a safe place and let it dry. I do the spray thing about very two months, and shake it inside out about once a week. After all this time, somewhere in and about 2 years, this has not deteriorated the bag in any way, as it still sucks anything I throw at it (chips, dust, chunks of turning explosions, sandpaper, rags, etc, etc, etc).

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected !

View dbw's profile


201 posts in 1604 days

#6 posted 03-07-2016 11:44 PM

sounds like the filter bag is clogged.

-- measure 3 times, cut once

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