# Shop vac dust bag questions



## InstantSiv (Jan 12, 2014)

Hi, I have 2 questions about shop vac dust bags.

My setup: Shopvac with the foam filter, cloth filter, and dust bag. It's connected to a 5 gallon bucket separator which is than connected to the router's dust port.

1. I've emptied about 10 gallons worth of dust out of the 5 gallon bucket separator. The dust bag is less than 1/8th filled. Question is how do I know when the dust bag is clogged and should be changed out?

2. What kind of micron rating can this type of setup filter down to?


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## Grandpa (Jan 28, 2011)

I am not sure of the micron but the bags are far superior to the filters. They might let .5 dust through though and that is the bad stuff. As far as knowing when they are clogged, they will stopped picking up dust and chips. Change it when it stops working. The fact that it doesn't stop picking up chips might tell us that it just blows the fines back into the air. NOT GOOD!!


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## InstantSiv (Jan 12, 2014)

Hi grandpa, Sorry I'm not understanding the part where it doesn't stop picking up chips and that it might just be blowing the fines back into the air.

I believe the separator to be very effective because I see a lot of fine dust in the separator that looks and feels like flour and because the dust bag is less than 1/8th filled after about 10 gallons of dust through the system. Am I wrong and the fine stuff is not being captured?


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## wapakfred (Jul 29, 2011)

About the only way I know to judge whether any filter media is clogged is by the air flow through it: if you loose suction, it's getting clogged. On my DC I've installed a gauge to measure just that happenstance. I think you're over thinking the whole thing, if it's not picking up the dust as well, change the bag/filter/whatever is clogged. As for the micron rating, I have no idea but I do know the bags rated for drywall dust are the tightest you can get (AFAIK) and they absolutely trap everything…I've been through quite a few, they are my favorites. So of the other bags aren't quite as tight, but the ones I've used seem to do a pretty good job.


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