My dust collection system is already up and running. I am about to add a new toy to the mix and started looking at my whole collection system again with a critical eye.
Currently, I have a 1.5 HP dust collector attached to a trash can separator and then to a series of ducts, blast gates, etc. After reading some dark web blog posts I decided to vent the dust directly outside, thus avoiding those pesky filter bags altogether.
So now I am thinking about avoiding the separator as well. And maybe instead of blowing the dust outside, I started to wonder:
Why couldn't I just blow everything - fine dust, wood shavings, loose change, whatever - directly into a sealed container? That is, what is the purpose of the filter bag in the first place?
It seems to me that the whole point of the separator is to preserve the life of the filter (less stuff reaching it so less stuff clogging it up). But I don't even have a filter to preserve. I've also heard conflicting info about separators:
- They will drastically reduce your airflow
- It's a closed system so it won't matter
If airflow is indeed being compromised by the separator, then my thought is remove it and convert it into a sealed container that collects everything that goes through the system, without worrying about how many microns it is.
Am I missing something elementary here?
Original poster here...
Thanks jdv! (And Graphus & blacksmith37)...
OK, a few clarifications. Regarding the physics of creating a negative pressure scenario, my shop is in Hawaii and only has three walls and windows that are permanently open. Air flow is not a problem. Rust, on the other hand... But that is a different topic. Also, this is a hobby shop. I putz around in there as much as I can, but it is definitely not a commercial shop. I don't create enough sawdust to be "that guy". The annoying noise of the woodshop is most certainly a bigger nuisance to my neighbors than the dust. But I live in an upscale redneck neighborhood so we're all good. :)
I still have bad memories of being the low person on the totem pole awhile ago at a shop I worked at. I was the newbie who had to clean out the filter bag. It always struck me as odd that so much effort was put into carefully collecting the dust in the shop only to dive headfirst into the filter bag and make a huge messy dust cloud. I like the idea of those pleated filter bags that have the butter-churning-type cleaner, but honestly this stuff gets expensive! Once I built my shop and started designing the dust collection system, I was determined to make it work well and be as hassle free as possible. The idea of venting directly outside appealed to me. My shop is built on a deck that is about two feet above the ground and the dust is vented underneath the deck. I have one plank that is not screwed down so I can monitor the end of the hose and make sure nothing weird is happening beneath my feet. The shop itself has almost constant trade winds but under the floor is still air due to the fact that the shop is built alongside a rock wall that blocks the prevailing winds. So in other words, the fine dust that doesn't end up in the separator doesn't really blow around, it just kinda settles onto the gravel below my shop, virtually undetectable to the eye (well, so far).
I guess the only reason I was thinking of removing the trash can separator from the system was to recapture as many CFMs as possible. And my follow-up thought was, if I remove the separator, then I will end up blowing a lot more dust under the deck (rather than just the finest particles) which could in fact become a problem. Which led me back to contemplating a more proper collection system whilst avoiding the hassle of the filter bag.
I think what I will do is temporarily by-pass the separator and do some sort of makeshift test to see if I do actually get more suction without it. Maybe I am trying to solve a problem that doesn't exist.
Thanks again! I appreciate everyone's thoughts... Aloha!