Dust collector problem

[jscott2]

My 1 hp DC has the cloth bag on top and a plastic bag on the bottom.  It was working well as I was mostly cutting on the table saw and doing some routing but lately it has been blowing dust out of the top of the bottom bag.  I'm doing mostly sanding and scrolling so there is much finer dust being generated and some of it leaks between the bag and the metal ring of the DC.

It really blows out when I shake the upper bag to dislodge the dust that has collected on the inside of the bag.  

The lower bag is slightly larger than the metal ring so there are a few wrinkles where it is clamped to the ring.  The dust seems to come mostly at the wrinkles.  I've tried to pull out all the wrinkles but even where I neatly fold over the plastic to take up the slack, the dust blows out.

I've thought about duct taping the bag to the metal ring but the residue left by the tape would be messy.

Has anyone run into this problem and how did you solve it? Or, do you have any suggestions?

Thanks,
Jim

[dgman]

Hey Jim, I have a 1hp dust collector, but have felt bags both on top and bottom. After thinking about this it dawned on me that what you need is some felt weather stripping around the metal ring, something like this: http://buyfeltonline.com/product/grey-felt-weather-stripping
You can probably find something like this at your local home improvement center.

[Al W]

Fine idea, might just have to try that myself, even though I am not current experiencing any blowby, still a fine idea.

[Rapid Roger]

I think that your top filter bag needs a good cleaning. Take it off, take it out side and give it a GOOD shaking, turn it inside out and shake it some more. Maybe use the shop vac to suck some of the dust off of it and re-install. See if it doesn't "breathe" better.
Just an idea that has helped me from time to time.

Rog

[jscott2]

Rapid Roger was right.  I have been shaking the bag while it was on the DC and thought it was "clean".  When it came off, it was caked with a layer of fine dust.  Getting it off made quite a mess in the yard but, after blowing it with compressed air, the bag was again white on the inside and the DC is back to normal.

dgman, your suggestion was to be the next step, but fortunately doesn't seem to be needed.  Still it was a good idea.

Thanks to both of you.
Jim

[lazygit]

Sorry to be the bearer of bad news Jim, but these bag type "dust collectors" are only chip collectors, and for the small stuff they are merely dust pumps. http://billpentz.com/woodworking/cyclone/ will give you several weeks reading on the subject. It's a really good site, and will allow you to live longer and not die from a wood dust generated condition. One of my customers did a lot of woodwork and to see him go downhill was not a pleasant experience.

I built one of Bill's cyclones for a shop vac and it worked well, but I have my shed open at either end so it gets cold, but it is reasonably dust free.

The microclene type dust thingies get a mention on Bill's site. A way to waste money IMO after a bit of reading.

[jscott2]

My dust collector does collect at least some fine dust because the bag plugs, that's what started the thread.  It seems the problem with the scroll saw is that is makes mostly very fine dust.  The DC does collect some of the fine dust, that's why it plugs and forces dust from around the seal of the bottom bag.  Is it 5%, 50%, or 95% efficient is another question.  Even with a 1 micron bag, I suspect it's efficiency for fine dust is on the low side.  Chips and table saw dust don't plug the filter bag the way the scroll saw dust seems to. 

I'm wondering if a cyclone before the dust collector would remove most of the fine dust.  My DC is a Busy Bee Craftex, 1hp with a 4" inlet.  Does anyone have any experience that would tell me it would be worth the effort to build a cyclone?  Can't afford a commercial one, at least for a while.


Thanks for your comments.
Jim

[Keefie]

I only have the chip collector type extractor, so I built myself a "Thein Seperator" since then I have only had to clean the bags on the extractor twice this year, 95% of dust and all but 100% of shavings (when woodturning on the lathe) is seperated by the cyclone. have a look at the plans here - http://www.cgallery.com/jpthien/cy.htm  If you look, about halfway down the page there is a link to a demo video.
Hope this helps.

Keith

[lazygit]

My build of Bill Pentz's cyclone collects all the sawdust and a large proportion of the finer dust, so I rarely have to clean the vac bag out. Cyclones will usually collect about 90% of what goes in, and you need special ones for very fine dust. If you can, it's better to exhaust outside, then it's no problem.

The plan I used is no longer on Bill's site, but www.clearvuecyclones.com have the CV06 available.