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Dust Collection Upgrade to hard pipe questions

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Forum topic by eflanders posted 01-12-2016 09:06 PM 1588 views 0 times favorited 33 replies Add to Favorites Watch
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eflanders

87 posts in 1314 days


01-12-2016 09:06 PM

Topic tags/keywords: dust collection air flow separator cyclone

In my basement based workshop I currently have 7 machines hooked into my Delta 1.5 hp DC unit. All lines into it are currently 4” flex pipe and I have never had any issues with collecting any shavings. Notes: a). I dress quite a bit of rough-sawn lumber and can easily fill a bag of shavings in a shop work day. b). Recently I added a Wynn nano filter to the existing DC and it was a good improvement in the ultra fine dust collection that was needed. (Air-born fine dust previously was having to be extracted via 2 suspended air filtration units which only catches about 80%-90% of the ultra fine dust.)

Could I improve things even more by adding a cyclone or separator?
Have you noticed a substantial improvement in suction using hard pipe vs. flex?
Will I gain more air flow by using a 6” hard-pipe main line with 4” flexible drops to each w.w. machine?
What connector(s) are used to go from the 4” PVC to the 4” plastic flex tubing?
Is the pipe o.d. different for schedule 20 vs. schedule 40 and does it require a different connection to the flex?
Other than keeping small cut-offs from hitting the DC impeller, what advantages does a separator really give you?
How easy and messy is it to empty the dust / shavings bin when using a top-hat, baffle or cyclone separator vs. the plastic bag currently on my DC unit?
What connection do you use from the cyclone or separator to the dust bin?
I have a maximum ceiling height of only 8’. Based on this, would you recommend a cyclone, baffle or top-hat separator and WHY?

Thanks in advance for your insight and advice!
Eric


33 replies so far

View rwe2156's profile

rwe2156

2193 posts in 944 days


#1 posted 01-12-2016 10:49 PM


*Could I improve things even more by adding a cyclone or separator?

Cyclones degrade CFM’s. The only real advantage is chip collection.

Have you noticed a substantial improvement in suction using hard pipe vs. flex?

There will be a significant increase in air flow, especially with this much ducting.

Will I gain more air flow by using a 6” hard-pipe main line with 4” flexible drops to each w.w. machine?
Absolutely!

What connector(s) are used to go from the 4” PVC to the 4” plastic flex tubing?

I slip the flex right over the pvc. It helps to remove a few inches of the wire from the flex then just clamp.

Yes. For sch 20 the flex will slip over.

Other than keeping small cut-offs from hitting the DC impeller, what advantages does a separator really give you? How easy and messy is it to empty the dust / shavings bin when using a top-hat, baffle or cyclone separator vs. the plastic bag currently on my DC unit?
Much easier!!

What connection do you use from the cyclone or separator to the dust bin?
About a 2 foot piece of 6” flex.

.I have a maximum ceiling height of only 8 . Based on this, would you recommend a cyclone, baffle or top-hat separator and WHY?
The Jet cyclones are a little over 6’ tall. There may be others.

- eflanders

-- Everything is a prototype thats why its one of a kind!!

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Fred Hargis

3938 posts in 1956 days


#2 posted 01-13-2016 07:06 PM

Just a point about the improvement of the ultra fine dust collection you perceived. The filter will undoubtedly separate more of the fine dust particles from the air stream than whatever it replaced. But real improvement would be in capturing more of the fine particles and it didn’t do much to improve that part. It takes air flow to catch the finest dust, as you see the larger stuff is fairly easy to catch. Unless you catch them at the source, they are still getting into the ambient air. So any of the improvements you want to make that will increase air flow would be a good thing. One other thing, the air filtration units are a good thing, but do little for your health….by the time they catch the dust it’s already in your lungs.

-- Our village hasn't lost it's idiot, he was elected to congress.

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bkseitz

294 posts in 773 days


#3 posted 01-13-2016 07:39 PM

Many of the questions have been answered above. Just to add-on: Cyclone will lower CFM, but improve dust collection by protecting your blower from large chips, etc. Duct size and dust collection efficiency is not a certainty a few factors interact and effect that: Blower CFM, smoothness of duct surface, straightness of airflow path, distance between blower and collection point, resistance of filtering surface, and size of ducts. The basic advice is reducing resistance of airflow is what gets you better collection.

If you’re not in a hurry, check out my Project Blog on Air Quality. I’m in process of building out several systems to improve air quality in my shop: Dust Collection, Shop Air Filter System, and Power Air Respirators. It is not likely to be as detailed as Bill Pentz site, but may help the average joe on a budget like me

-- bkseitz, Washington "if everything is going well, you've obviously overlooked something"

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AZWoody

693 posts in 687 days


#4 posted 01-13-2016 08:34 PM

I really am not sure that going to 6” will help in getting more cfm. If your motor and impeller are not big enough, your air speed inside a pipe that size will not be sufficient to move the particles and you’ll end up plugging up and having more problems than with a 4” pipe. I think 5” might be the largest with what you have but can’t be more positive unless you know the fan curves for what you have.

Another benefit of some sort of separator, other than protecting the impeller is it will improve the life of the filter. It will help keep particles down that get to it so there will be a much longer time in between needing to clean and or replace.

As for types of separators, in my experience, unless you’re trying to move lots of volume they’re going to work pretty much the same. I’ve done side by sides of the Oneida super dust deputy cyclone and a plastic separator that sits on top of a trashcan and there was no difference in terms of cfm loss.

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AZWoody

693 posts in 687 days


#5 posted 01-13-2016 08:36 PM



One other thing, the air filtration units are a good thing, but do little for your health….by the time they catch the dust it s already in your lungs.

- Fred Hargis

This is something very important to understand. If you’re not catching it at the tool, you will breathe it, unless you’re wearing a respirator of some sort.

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Sundowner

36 posts in 1398 days


#6 posted 01-13-2016 08:44 PM



I really am not sure that going to 6” will help in getting more cfm. If your motor and impeller are not big enough, your air speed inside a pipe that size will not be sufficient to move the particles and you ll end up plugging up and having more problems than with a 4” pipe. I think 5” might be the largest with what you have but can t be more positive unless you know the fan curves for what you have.

- AZWoody

this. you need to match your piping size to collector size, the length of the ducting runs, and the needs of the equipment it serves. I have a 6” PVC ducting trunk line that runs about 25’ off of 7” inlet on a 3HP Oneida. After that, it drops to 4” PVC then flexible ducting line to the smaller tools like the band saw and chop saw, but stays at 6” straight through to the planer/jointer and table saw. if you go big the whole way, even on a big collector, you will lose velocity in the duct. you need to step-down the duct diameter the further out you go to maintain enough velocity to carry along the dust and chips.

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bkseitz

294 posts in 773 days


#7 posted 01-13-2016 08:50 PM

@AZWoody, Air Filtration Units can assist but most of the common placement is wrong (overhead). Placing an Air Filtration Unit overhead actually makes the problem worse immediately in that you are creating an airflow from the floor up past your head to breath in. Placing it at ground level or below bench level with exhaust piped above will create a downward flow of dust away from you to breath in.

I’m brainstorming with Dick Wynn on a cost efficient (read that as cheap) air filtration approach to do such see blog. I hope to have test results to post by this spring/summer. I had used a similar method for creating IT clean rooms which required much more control over particles

-- bkseitz, Washington "if everything is going well, you've obviously overlooked something"

View JeffP's profile

JeffP

573 posts in 855 days


#8 posted 01-14-2016 12:33 AM


One other thing, the air filtration units are a good thing, but do little for your health….by the time they catch the dust it s already in your lungs.

- Fred Hargis

This is something very important to understand. If you re not catching it at the tool, you will breathe it, unless you re wearing a respirator of some sort.

- AZWoody

I’m sure this advice was well intentioned and believed by those who posted and re-posted it, but I call bullshit on this notion.

If you’re only in the shop for a couple seconds while you cut/route/plane/sand something, then sure…this would be true.

But if you are a normal woodworker this is bull hockey. Woodworkers make dust and then they stand there and breathe it for awhile before they make some more.

No question that removing as much as possible at the tool is a good thing. Does that mean that removing some more from the air after it escapes from the tool does no good. No. it. does. not. period.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

View eflanders's profile

eflanders

87 posts in 1314 days


#9 posted 01-14-2016 12:51 AM

My ceiling hung units do a lot to prevent dust from travelling outside of the shop. But I am going to try to relocate one of them to the floor as that idea seems to make a lot of sense see to me. It’s worth a try anyway, right?

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AZWoody

693 posts in 687 days


#10 posted 01-14-2016 05:31 PM


I m sure this advice was well intentioned and believed by those who posted and re-posted it, but I call bullshit on this notion.

If you re only in the shop for a couple seconds while you cut/route/plane/sand something, then sure…this would be true.

But if you are a normal woodworker this is bull hockey. Woodworkers make dust and then they stand there and breathe it for awhile before they make some more.

No question that removing as much as possible at the tool is a good thing. Does that mean that removing some more from the air after it escapes from the tool does no good. No. it. does. not. period.

- JeffP

You have it backwards. If you’re just cutting for a few seconds then leave, then you really aren’t going to breathe in as much but if you’re in the shop, for long periods, standing and working in a room full of sawdust, then it’s a health problem. Maybe you’re not having issues but there are people that do. The trade off is in what money people are willing to spend and only they can prioritize where the safety and health risks.

An ambient air cleaner has to suck dust out of the air. Your lungs, suck dust out of the air. If it’s in the air for one, it’s in the room for another. An ambient air cleaner does not take all the dust out of the room within seconds. It can take hours. Just because the cfm rating may make people think they’re circulating their shop space x many times per minute doesn’t mean it actually is. Those type of filters are not great at suction. Within a couple feet, maybe that, they can pull particles into the filter. Go further out and dust will be hanging there much longer and may end up settling to the ground before it has a chance to get taken out of the air. Then, it gets kicked back up from walking by.

There would actually need to be one large filter and fans to help circulate or have several filters in various parts of the shop to create some kind of flow to keep the air moving. In a rectangular shop, which most have, there are so many dead spots, such as corners, around machinery, workbenches, etc that stop the movement of air there is just no way a single filter can effectively clean a shop’s air.

That is why I said there still needs to be use of a respirator if you cannot collect the dust at the machine.
Calling bullshit because something isn’t important to you dismisses the health effects that sawdust can and does have on many people.

View Fred Hargis's profile

Fred Hargis

3938 posts in 1956 days


#11 posted 01-14-2016 05:44 PM

Calling bullshit because something isn t important to you dismisses the health effects that sawdust can and does have on many people.

- AZWoody

+1, being in denial about the health risks isn’t unusual…I know a few smokers who claim it doesn’t harm their health.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Bill7255's profile

Bill7255

354 posts in 1748 days


#12 posted 01-14-2016 06:35 PM

No doubt catching the dust at the source is the best. However it is very difficult or impossible to collect every particle. Some will escape. The purpose of the air filtration unit is to capture as much of this as possible, not letting it settle. Just walking through the shop will stir up dust that has settled, especially the really fine dust. I run my air filtration when out in the shop and set the timer for two hours once I leave. IMO you need good collection at the source and it is beneficial to run a air filtration system.

-- Bill R

View bkseitz's profile

bkseitz

294 posts in 773 days


#13 posted 01-14-2016 06:54 PM

As mentioned above I’m working on a new approach to air filtration this year here is the brainstorming I’ve come up with at present using concepts from IT Cleanroom designs. Not fancy but the idea is to create a constant downdraft away from your head and therefore your lungs rather than have it drift upwards to an overhead air filter.

I’ll be testing out the approach after I finish my dust collection project this month. Results to be posted for each after completion as well as handed over to Dick Wynn whose been helpful in brainstorming ideas to keep the costs reasonable.

-- bkseitz, Washington "if everything is going well, you've obviously overlooked something"

View AZWoody's profile (online now)

AZWoody

693 posts in 687 days


#14 posted 01-14-2016 07:42 PM


No doubt catching the dust at the source is the best. However it is very difficult or impossible to collect every particle. Some will escape. The purpose of the air filtration unit is to capture as much of this as possible, not letting it settle. Just walking through the shop will stir up dust that has settled, especially the really fine dust. I run my air filtration when out in the shop and set the timer for two hours once I leave. IMO you need good collection at the source and it is beneficial to run a air filtration system.

- Bill7255

With the proper size dust collector, proper ducting and modifications to the machines, collecting the dust to make it safe to breathe in the shop is possible. If that was not the case, OSHA would be shutting down every furniture shop in the US. The question is, is it affordable, or a priority in terms of cost for the hobbyist.

I agree that an air filter will help, but not in tight conjunction with a dust collector so that you can leave off the respirator or some kind of dust mask. In the end, you can do what you like in your own shop and home. Others can make decisions on what is important for themselves.

Bkseitz, I believe you are on the right course but depending on the size of the shop, there still needs to be multiple units or fans in other areas of the ceiling to create the downdraft and proper circulation. The dust has to be moved to the filter because after a certain distance, the blower does not have the suction to draw particulates to it. Air flow throughout the shop is key and square rooms filled with machines and tables kill the flow.

I am interested to see what you come up with. I’m also trying to figure out some other ways to grab the dust from some of the things that I do in my shop that I can’t use my dust collector on.

View clin's profile

clin

513 posts in 459 days


#15 posted 01-14-2016 08:10 PM

I find bkseitz idea intriguing and it has merit. Whether practical or not, we’ll have to see how it work out.

One other thing, the air filtration units are a good thing, but do little for your health….by the time they catch the dust it s already in your lungs.

- Fred Hargis

This is something very important to understand. If you re not catching it at the tool, you will breathe it, unless you re wearing a respirator of some sort.

- AZWoody

I don’t completely agree with this. While an ambient filter is not optimal compared to collecting at the tool, and won’t guarantee you breathe in no fine dust, you sure as heck or going to breath a lot less in than if you don’t run it.

As mentioned, there are dead spots etc. But these filters move something like 1000X more CFM than your lungs. The dust is much more likely to go into the filter than your lungs. Though again, some will get in your lungs.

And I agree with the comments concerning that fact it doesn’t clean the air as fast as a simple calculation based on CFM. Even with complete airflow (no dead spots), it would follow an exponential decay. But I’m sure that is wildly over estimating how quickly it works.

I don’t have a DC yet, just Dust Deputy and shop vac with HEPA filter. I also run a Jet ambient filter. But I wear a respirator any time I’m using the table saw or router. And I keep the respirato on for at least 15 minutes (usually longer) after running those tools.

-- Clin

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