DC...wow what a headache

[Dave Sims]

Reread Bill's cyclone research. I am in the market for my 1st dust collector. Onieda is local to me ~15 minutes away. I would just like to sort some stuff out. According to Bill, each machine needs about 1000cfm at the machine to get the fine dust. I think he means .5 micron. 1000cfm needs 500 sq/ft filter. Looking at clearvue cyclones, (Bill approved) the units have two wynn filters for a combined 600 sq/ft. Using his rule of thumb these filters should be mated to a 1200cfm max motor. I find it hard to believe that the 5hp Leeson motor only sucks 1200 cfm.

Seems like Bill implies everything on the market is rubbish except his cyclone.

Onieda's filter is a hepa and according to their website it is only 110 square feet. According to Bill that is enough to support 220 cfm at .5 micron.

I have a headache now. I was really considering going with 1.5 - 2 hp onieda/grizzly/jet/whatever. Bill just rained on my parade. super sadface.

Maybe I missed something in Bills literature, or am missing the concept all together, but there is nothing manufactured that will save my lungs except a clearvue cyclone?

With that being said I am going to go to the garage and sand my bed, while holding my breath.

[frank shic]

dude, i had a major inferiority complex after reading that article as well but you know what? i'm still breathing pretty well and my delta DC collector is good enough for me right now...

[David Kumm]

Dave, different filter media have different requirements in terms of sq footage. In general though the finer the filter and the less sq footage the more pressure drop you have to compensate for. That is why a 5 hp 15-16" impeller tend to operate in the 1000-1400 cfm range. What you need depends on your machines and their requirements. More cfm at higher pressure is generally better but if the machine port is 4" a 3 hp 14" impeller is likely to give about as good a flow as the larger unit- depending on piping and a million other things. The whole filter thing is a little marketing as well. Wood dust generated even when sanding is not so small as to require hepa or hepa like filters if the system is done right. They are an extra line of defense but come at a cost. They need to be monitored as they fill up more frequently and if not watched can plug until the cfm drops to the point where the dust is staying with the machine and in your lungs. My dylos ran basically the same numbers with my tube filters as it does with MERV 13-15 cartridges so I'm on the fence until I season my cartridges more. Cartridges are definitely for lighter use systems. Commercial systems require bags with shakers or pulse jet cleaners as cartridges plug in minutes and hours in that environment. Dave

[Brian Brightwell]

I worked maintenance in a chemical plant for 22years where we made plastic powder so you can imagine what my lungs have seen.
We had lots of dust collection systems and they all vented outside not into interiors.
I plan on having my whole system outside with only the pipe inside.

[glenn bradley]

My bagger was good enough until it wasn't. The damaged tissue means I now have to wear a respirator even when hand sanding if I don't want to spend a couple days off work with a disabling ear / head ache.

Dust collection: Do it right. Do it now. There's no do-overs if you damage yourself.

[Dave Sims]

I hear you loud and clear glenn.

I will have to vent inside for now. He are hoping to buy my wife's grandparents house in a year or so. They are slowing down and the house is too much for them. I will vent outside in the "new" house for sure.

I would consider my application for lighter use. One machine at a time. I think I have the basics down. 6" piping, shortest runs possible, fewest elbows, flex hose the last few feet. I am thinking a 1000 cfm machine would fit the bill. Still not sure if the extra $ for the onieda will bring any big improvements.

thanks for the help guys. back to sanding.
.

[ian maybury]

I think Bill was writing when there was minimal acceptance of anything much beyond the typical 1HP bagger, and was hitting hard in an effort overturn the dogma. He took a lot of flak too. There's some more choice on the market now.

The Clear Vue system runs a 5HP motor, but seems to depending on motor efficiencies and the like to pull more like 4HP ± on a typical large double garage sized shop on 6in ducting. i.e. It's capable of moving more CFM with larger ducting and reduced restriction.

There's a few of us that have put a lot of time into dust system components, but it's still damn difficult if not impossible to definitively bottom how well or how badly the various systems perform. There simply isn't (at least not in general circulation) reliable test data available, and the mags don't help by ducking the issue for want of in depth knowledge and/or fear of offending advertisers. At least not for filters and cyclones - the Cincinatti Fan tables do seem to check out time and again as reliable.

We really do put it up to ourselves by setting out to filter and recirculate all of our air. As Brian said above (and Bill Pentz too) the rational thing to do is to exhaust our return air outside - this minimises the health risk, and maximises filter life. The issue we seem to have as smaller users is that the relative cost of exhausting heated air is greater for us than for a large multi person building.

The big requirements to be met are probably (a) pull enough CFM through a reasonably effective hood to ensure decent chip and dust collection, and (b) if recirculating ensure that whatever means of separation you use (filters and/or cyclone and/or outside exhaust) that it truly works so that the air you breathe is clean.

After that it's partly engineering (matching fan and system curves - and that data is fairly easily available), and partly what you (a) end up believing/don't believe regarding the claims as to the capability of the variously available bits of hardware, and (b) whether you are prepared to spend to overcome uncertainties.

Like most things in life it in the end is a lot to do with belief systems, and willingness to be led by the available data (such as it is) and to do the work to bottom the questions as best we can. Letting go enough so that our radar/intuition can work ends up being quite a large part of it - lots of us get waylaid by pre-conceptions to do with how we use money, how we judge credibility and our personal attributes. (willingness to work/attention span etc)

The one thing that does seem to be clear is that it's not something to skimp on. For example as David says HEPA or similar cartridge filters may well be overkill. Against that though, they are at least a known quantity. Ditto the matter of higher CFM systems. Yes, fine tuning and careful set up may well make it possible to do a decent job with less airflow, but against that the big numbers do inevitably make for more robust dust collection performance.

ian

[Phil Thien]

I would consider my application for lighter use. One machine at a time. I think I have the basics down. 6" piping, shortest runs possible, fewest elbows, flex hose the last few feet. I am thinking a 1000 cfm machine would fit the bill. Still not sure if the extra $ for the onieda will bring any big improvements.
.

I think you have a good handle on it.

You have to be careful, dust collection is a religion (cult?) for some.

IMHO, spending some extra money on an ambient air cleaner would be a wise investment. No DC will catch everything at the machine.

[Gary Max]

Think about this---- are you going to rip the carpet out of your home and sleep in a plastic bag on the floor. The real issue to me is that you reduce the amount of sawdust you breath in.

[Dave Sims]

thank you all for the helpful info. Dust collection is a bit of a cult. I dont think i will lose any sleep with an air cleaner and a descent dust collector.

[Brian Brightwell]

With all the cost and complexities,if I had to do it all over again I think I would just use hand tools.

[Steven Green]

Gary nailed it. Ignoring the dust problem will damage you. Bankrupting yourself and losing sleep ain't too smart either. We need to do the best we can as responsible individuals. Simple as that

[Jim O'Dell]

Keep in mind the background that drives Bill P. His health. The dust almost killed him. So there is reason for his almost religious fervor about dust collection. The biggest thing for me was the separation the cyclone does. Bill did a lot of research to end up at the ratio of the cone/length for, in his opinion, the best separation of fine particles. I've had a Clear Vue in use for 5 years now, and while I exhaust outside, I see absolutely no evidence of dust on my exhaust louvers. I feel I got a better system for the money than I could have gotten from any of the other manufacturers. But that is my decision. I'm sure most of the major brand cyclones do a great job, much better than a bag system would do. The filters help catch some of what the cyclone can't separate. Both are important. Jim.

[Bud Millis]

Dave, Oneida makes and excellent system. They are local and the best place to get all the supplies. That's were I get mine. Having them shipped in from else where is just too $$$$$. HEPA filters, venting outdoors (ck local code first, also your neighbors may take offense if they are close), Ambient air cleaner. Although for these to work, which many fail to understand how they do, it needs to be on prior to, during and after making the dust. It cleans the air by turning it over in the shop. A properly fitting respirator that is effective towards what you are doing. Even something like Festol sander and vacuum. Do what you can to minimize the dust. Its the dust that is smaller than .5 microns that travel far down into the lungs, reaching all the way down to the alveoli. It is here that the gas exchange takes place for the body. Also you cannot forget the sinus cavities - dust can get into there and cause problems as well.

You need to get the best dust collection that you can afford.

[David Kumm]

With oneida being close and saving the shipping cost you have to consider that to be a pretty good discount. The clearvue cyclone is the better separator but Oneida makes a strong unit with a good motor. Impeller design is a toss up between the two. If you go hepa-like filters- there are no true hepa round cartridges- you want a big enough unit to allow for the pressure drop of the filters and cyclone. Keep in mind that with all the talk about Hepa filtration there isn't much documentation as to how much <.5 micron dust is generated by woodworking and none of the overhead ambient cleaners we buy filter even close to MERV 15 let alone 17+ Hepa standards. Most come stock with MERV 10 type filters so I have to wonder if we are well served to use the finest filters in DC rather than more traditional MERV 10-15 and get better overhead filtration where the filters would last much longer and are disposable. True Hepa are generally disposable and not cleanable. From what I can find they are pretty costly. Wynn does make an after market inner filter for ambient units that are in the MERV 14 area. Dave