Dust Collection Suggestions

[ckrysiak]

First I would like to thank everyone for their posts, they were extremely helpful in setting up the ShopBot. I've had the 48x48x12 PRSAlpha ShopBot in operation now for about two months and have been fortunate enough to get enough business to have already paid for it!

However, I badly need to upgrade the dust collection system as I've only been using a Craftsman shop vac. I fabricate parts from ceramic fiber insulating board which you can not get a chip load from when machining, it produces very fine dust particles (the closest thing I can think of to describe the particle size would be if you were to machine drywall). The shop vac actually works fine for about two minutes of machining before the filter clogs up.

I've purchased a dust collector from Harbor Freight (see attached picture) and want to add a separator using a metal trash can with a cyclone lid. My question to everyone is has anyone had any experience with a separator in a dust collection system involving very fine dust particles? If so, what type of cyclone lid design did you use? I have a feeling the separator will be useless in my application because in order to get the flow rate needed to actually extract the dust at the router, the flow rate will be too high at the separator and will just pull the dust through to the dust collector. Any thoughts?

Thanks in advance for your time, Chad.

[kurt_rose]

I have the same DC but I plumbed it outside and put the DC under a shed roof. Use a switched outlet to turn it on and off.

[cowboy1296]

This is the one that I use. http://www.grizzly.com/products/30-Gallon-Dust-Collection-2-Stage-Cyclone-Separator/W1049

I fits on top of a trashcan. I think that I loose a little power but it does the job. Not sure that it was absolutely necessary but I did run and connect my ground wire inside of the trash can. I still have to empty my bag on the dc but not nearly as often. Its a lot easier to carry out the trashcan than remove the bag.

[dana_swift]

Cyclone design is done based on the size of the particle you wish to have settle out, and the CFM of the air flow. Designing a cone is not particularly difficult if you care to build your own, there are equations that specify the cone parameters for any given amount of filtration.

The Wikipedia has the heavy math, you can safely ignore, unless you want to study how the physics of the separation works.

Here is a link to a paper that has both the equations and the calculus. Read the first part :). It explains in detail how they work, and what the tradeoffs are.

http://repository.tamu.edu/bitstream/handle/1969.1/2192/etd-tamu-2004A-BAEN-Wang-1.pdf

I have seen other web pages with just the equations, but at the moment I cant find one. If you want something specific, build one. If it doesn't work well enough.. build another one! Usually much less expensive than buying one, I wish I had built mine, but I didn't have any special requirements. If I ever want another one, I will build it.


Hope that helps-

D

[blackhawk]

Chad - Check out this website. Call them on the phone and they can most likely help you out.

http://wynnenv.com/woodworking-filters/

[stump]

I built a Thien Cyclone Separator and it has worked great. I do a lot of sanding as well as running the 'bot. I have emptied the garbage can many times and still don't even have the bottom of the bag covered in my dust collector. Info is at this link: http://www.jpthien.com/cy.htm

and the plans are on the "discussion forum". I did modify the design to use a 4" hose instead of the smaller size shop vac size.

[donek]

I have 4 of the harbor freight DCs in my shop. The only problem we've encountered is with the switches. We've had to replace them due to too much dust in them. I'd go with filter bags top and bottom and forget the cyclone.

[br928]

If you really want to know about dust collection, spent a few hours here: http://billpentz.com/woodworking/cyclone/index.cfm

Unless your bag collectors are outside or in an unoccupied room, a good cyclone is the only healthy choice.

[Bob Eustace]

Chad, please oh please read the document Stan suggests as it really is knowledge you need to have to prevent serious health problems that can creep up on one without you noticing. The quote below gives the gutze of the article.

Fine dust harms everyone exposed and toxic dust can blindside us quickly. A Google search on PM health risks shows over seventy seven million references. Although these references contain considerable nonsense, the peer reviewed medical research shows every exposure to fine dust causes a measurable loss of respiratory function, some of this loss becomes permanent, and the higher and longer the exposure, the greater the damage. After I installed the top magazine rated cyclone system with upgraded fine filter fine wood dust blindsided me. Like most other small shop dust collection solutions my cyclone created a bad false sense of security. It left a clean looking shop while building dangerously high levels of invisible fine dust. I had no warning or clue that my shop and attached home were dangerously contaminated. Poisonous chemicals in wood cause a range of toxic reactions including irritation, chronic infections, wood related diseases, worsening allergic reactions, nerve damage, poisoning, and even increase our risk of cancer. Less than three months after installing this cyclone a worsening allergic reaction landed me in the hospital, cost 58% of my respiratory capacity, and left me still supplemental oxygen dependent over a decade later. Certified air quality testing three months after I stopped woodworking showed my shop and home contaminated with wood dust particle counts thousands of times higher than considered safe. Many now monitor their own air quality using affordable 0.5-micron Pro Dylos Particle Meters. They consistently find similar problems with almost every dust collector and cyclone system vented inside regardless of fine filter upgrades and vendor advertizing claims. Many report their clean looking shops contain so much fine invisible dust just walking around launches dangerously unhealthy amounts airborne. Many found their meters clearly show when a dog or cat walks through their clean looking shops at night. Sadly, I get about two emails a week from others blindsided by fine dust allergic reactions that forced them to either totally quit woodworking or stop working certain woods.

[adrianm]

Definitely go for the dust collectors in a building outside of your workshop.

90% of what I machine is MDF and that's really nasty stuff. I put on a full forced air respirator whenever I change the bags in the collector.

I used to use a separator system but stopped in the end at it just took me twice as long to empty it all out which is twice as long exposed to potentially nasty dust.