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Forum topic by jgt1942 posted 06-01-2015 07:22 AM 1717 views 1 time favorited 26 replies Add to Favorites Watch
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jgt1942

138 posts in 1356 days


06-01-2015 07:22 AM

Topic tags/keywords: dust collection pipe size pvc pipe metal pipe question

I’ve read tons of post regarding dust collection and still remain somewhat confused, thus I have a question regarding pipe size for my shop.
I have a Grizzly G1029Z2 2 HP Dust Collector and per the spec sheet it has an air suction capacity of 1300 CFM. I also has a 6” port on the intake of the impeller unit. I completely modified the Grizzly and connected it to a Thien Top Hat and the performance is SUPER! The Thien has a 4 inch intake and the suction at the end of my 4 inch 20 foot flex hose is very good. I have NOT measured the actual suction. The dust separation I get with the Thien is outstanding.
My initial though was to just make the unit portable and move it around the shop as needed. This turned out to be a bad idea because it is such a big hassle thus I want to install a permanent setup with fixed runs to each location. My longest run will be about 48 feet (this is to my wood lathe).
Only one machine port will be open at any one time thus the big question should I use a 5 inch run from the intake of the dust collector or a 4 inch. At each machine I will drop down to a 4 inch line if I use a 5 inch line for the runs. In my research I determined that a 6 inch line would be too big for the Grizzly thus this is why I’m considering a 5 inch line.
The big issue with the 5 inch line is the cost. I’m looking at Nordfab for the pipe and estimate the cost to be somewhere between $700-$850. BUT if I use 4 inch PVC (Schedule 40) the cost will be about $100 thus I have a huge incentive to use 4 inch PVC.

-- JohnT


26 replies so far

View rwe2156's profile

rwe2156

2200 posts in 948 days


#1 posted 06-01-2015 10:22 AM

I’m not expert, but I’ll tell you what I know and let others more knowledgeable than me chime in.
Even without knowing the layout or what machines you have, 4” is too small for ducting.
48’ is a really long run and you don’t have a big enough blower, IMO.
(Why are you trying to put DC on a lathe anyway?)

In my case, I only have a 1 1/2” 1100CFM rated collector (which I am planning to upgrade to a 3HP) with 6” main run pipes and 4” drops to machine and it works quite well, even with a cyclone under it. But My longest run is 20’ and all my big producers (drum sander, planer, jointer) are all within 8’ of the cyclone.

I haven’t measured anything, and I don’t know what info you’ve tapped into, but from practical experience, I seriously doubt your blower would not work with 6” pipe.

If you go with PVC, use Sch 20, not 40. Keep the 4” drops as short as possible.

Also, I would do some checking on the separator you are using. I’ve heard they aren’t the best way to go.

DC was/is one of the most confusing things I’ve gotten into ww’ing. There’s plenty of scientific data out there that will boggle the mind, but in the final analysis, I think if you follow some simple guidelines you’ll do OK and be able to get back to ww’ing.

1. Largest ducts possible.
2. Long sweeping 90’s
3. Organizing machine layout for maximum efficiency
4. Minimize outflow obstruction (filters) or vent outside if possible.
5. Whatever size blower you think you need, get a bigger one!

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

View BoardSMITH's profile

BoardSMITH

121 posts in 1731 days


#2 posted 06-01-2015 10:26 AM

You can use standard spiral pipe for about the same cost as PVC. You can get it from a local HVAC supplier and although it is a little harder to work with than Nordfab, the cost difference is worth it. Also check out The Blast Gate Company at www.TheBlastGateCo.com. I found their prices very reasonable as well as their shipping rates , customer service was exceptional and they shipped quickly.

-- David www.TheBoardSMITH.com

View DIYaholic's profile

DIYaholic

19180 posts in 2143 days


#3 posted 06-01-2015 11:03 AM

I would think 48’ is toooooo loooong of a run.
Try to locate the DC unit in a more central location, if possible.
Perhaps a different shop layout is another option.

What is the micron rating for the DC filter?
You should consider a cartridge filter with 0.5 – 1.0 micron filtration.
A DC will NEVER collect all the fine dust, so an ambient air cleaner should also be used.
IMHO, a DC is used to keep the shop clean….
An ambient air cleaner is to keep your lungs clean & you breathing!!!

Good luck, there are many options & opinions….

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View Fred Hargis's profile

Fred Hargis

3950 posts in 1961 days


#4 posted 06-01-2015 11:30 AM

Robert nailed it, 4” is too small. You could go 6”, PVC is a little hard to find but 6” snap lock is everywhere. The most air flow you will pull through 4” is closer to 400 CFM. But let me say: not knowing what you intend to do at the lathe (I only have a floor sweep next to mine) that 400 CFM may be enough for that…so more info on the total plan would be useful. Another thing to remember: if you go PVC be sure to use the ASTM D2729 (called by many names including soil pipe, DWV, thin wall, and a few others). Look for the spec printed on the side and do not trust Skippy Stockboy to hand it to you.

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

View RobS888's profile

RobS888

1988 posts in 1313 days


#5 posted 06-01-2015 12:33 PM

+100 for 2729!

It is inexpensive, lightweight and has a bell shape at one end so 2 pipes fit together without a connector. The greatest thing though is that my 4 inch flex pipe will just very tightly slide on with a clamp, so no connector for that. And in a really big surprise my Rockler blast gates would press fit into the end, so no connector their either. I didn’t need to use anty tape to seal the joints. Oh, they have 90 degree street sweeps that are long 90s and have one end that you need to go into the 4 inch flex pipe. Female to male, I bought all female to female connectors and was putting a small length of pipe to slide the flex pipe onto, then I found the female to male and it made it even easier.

My longest run is about fifty feet to my jointer/planer and it works fine.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View Redoak49's profile

Redoak49

1964 posts in 1456 days


#6 posted 06-01-2015 01:45 PM

I have also read all the articles and such and understand the issues. I priced out the costs for going to a larger duct.

I am running 4” PVC pipe and built my own blast gates. My pipe goes across the ceiling with PVC and use y junction and long radius bends. All of my bigger tools are closest to the dust collector and connect to the PVC with short runs of flex pipe.

Would larger sized pipe be better….of course BUT do I really need it. The system does a good job and there is little dust on things in the shop. With the saw if I use the over blade dust collection there is almost no dust in the air. My dust collection works MUCH BETTER since I put the Vortex cone retro fit and get much better collection with no build up in the canister.

I also have found that building custom dust pickups for each tool has made a remarkable difference. It required some playing around with them to find out what works. It is not only the suctioning CFM but also how close to the dust generation and being able to capture it.

I think it would be useful to try the system with just 4”. If it is not enough, then look at larger duct size.

View rwe2156's profile

rwe2156

2200 posts in 948 days


#7 posted 06-01-2015 02:19 PM

Redoak,

Before a major shop remodel in which I totally redesigned/replaced my DC, I was running 4” pvc.

After the R&R, I went to 6” and the difference is considerable, even with my little blower, the performance diff is huge.

At the time I thought 6” was way to big for what I was doing, but not so.
I wouldn’t say you need to redo your system, but if you ever do a remodel, definitely go to 6”.

DIY,

I agree with you about DC not = dust extraction. This is something only possible with a very expensive Pentz-rated system, which most hobby ww’ers do not need.

I think air scrubbers are fine, just remember before the dust gets to them, you’ve already breathed it in!
This is why there is no substitute for personal protection when working around drum sanders, etc.
Especially when working with materials like MDF a full face respirator is a must (not a dust mask!!) including the gas cartridges to filter out the noxious stuff like formaldehyde.

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

View Andre's profile

Andre

1023 posts in 1274 days


#8 posted 06-01-2015 03:07 PM

I have a 1.5 hp general D.C. unit with a 2 micron pleated cartridge filter standard 6” inlet y to 2 – 4” runs.
Ran 4” Pvc pipe up and over the roof (10’ ceiling) and back down to my 6”jointer and 10 ” Table Saw and 17”Bandsaw, separate blast gates and connected to a Veritas Cyclone lid on a garbage can on the jointer and tabls saw. Yes to get max. suction can only run one 4” opening at a time but get more suction than when I was running 25’ hose! I did buy a anemometer to test air flow before and after modifications. Learning to use the anemometer was a challenge in itself as area of test outlet needs to be calculated, never did like math! CFM, area equals pi radius squared kmph my head still hurts.LOL.

-- Lifting one end of the plank.

View RobS888's profile

RobS888

1988 posts in 1313 days


#9 posted 06-01-2015 03:45 PM

DC not = dust extraction

Why bother then? I’ve built my system to gather dust, I can watch a steady stream of dust go right off my wife’s lathe into the collector. I really don’t care about the chips, can’t breathe them in. My Jointer/planer is about 50’ away and the DC pulls practically everything that comes out of it. Even most of the dust from my table saw is collected.

We filled 8 of those large paper leaf bags last year with mostly dust from our second stage barrel. We put it in lunch bags and burn it in our fire place insert. We have a .5 micron cartridge on our DC. It is in a closet that is pretty much sealed and there is fine powder in there sometimes, but at least it isn’t in the rest of the basement or our lungs. If you are finding lots of dust it may be from your DC filter.

So I’m confused when I read that DC isn’t for Dust, when my only concern was the actual dust collection.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View AZWoody's profile

AZWoody

700 posts in 692 days


#10 posted 06-01-2015 04:22 PM


DC not = dust extraction

Why bother then? I ve built my system to gather dust, I can watch a steady stream of dust go right off my wife s lathe into the collector. I really don t care about the chips, can t breathe them in. My Jointer/planer is about 50 away and the DC pulls practically everything that comes out of it. Even most of the dust from my table saw is collected.

We filled 8 of those large paper leaf bags last year with mostly dust from our second stage barrel. We put it in lunch bags and burn it in our fire place insert. We have a .5 micron cartridge on our DC. It is in a closet that is pretty much sealed and there is fine powder in there sometimes, but at least it isn t in the rest of the basement or our lungs. If you are finding lots of dust it may be from your DC filter.

So I m confused when I read that DC isn t for Dust, when my only concern was the actual dust collection.

- RobS888

I think the main thing that he’s saying is that most dust collectors, as designed do not do a good job of pulling the finest dust particles from the source. Even if you have a .5 micron filter, the system doesn’t have the capacity to collect it at the machine for the filters to be of use.

In most cases, it takes a 12”+ impeller coupled with a 3-5hp motor to be able to give the airflow needed to get the finest of the dust particles that a woodworking machine produces. Those are the ones that can’t be seen but are now being blamed for many health related issues.

It sucks, because it’s expensive to really do it right. I’m in the process of redoing completely my dust collection as I had 4” pipe on 40’ runs and yeah, it looked like it was doing a good job but if you really started to look at the air quality with a light, it would leave behind much more than I noticed before.
Then, I started getting nosebleeds the evening or next morning after working in the woodshop.

That was the impetus to really go and put the money down to get this down right.

View RobS888's profile

RobS888

1988 posts in 1313 days


#11 posted 06-01-2015 06:05 PM



I think the main thing that he s saying is that most dust collectors, as designed do not do a good job of pulling the finest dust particles from the source. Even if you have a .5 micron filter, the system doesn t have the capacity to collect it at the machine for the filters to be of use.

In most cases, it takes a 12”+ impeller coupled with a 3-5hp motor to be able to give the airflow needed to get the finest of the dust particles that a woodworking machine produces. Those are the ones that can t be seen but are now being blamed for many health related issues.

It sucks, because it s expensive to really do it right. I m in the process of redoing completely my dust collection as I had 4” pipe on 40 runs and yeah, it looked like it was doing a good job but if you really started to look at the air quality with a light, it would leave behind much more than I noticed before.
Then, I started getting nosebleeds the evening or next morning after working in the woodshop.

That was the impetus to really go and put the money down to get this down right.
- AZWoody


I just redid our system 2 months back and I’m gauging it off of the dust from my wife’s lathe. I measured 300+CFM at the small hood by her lathe. She uses the lathe for hours at a time and it is the major dust producer, so it was the gauge as to whether the system was working well.

So even though I see a cloud flying like smoke into a vacuum, I’m not getting the smallest particles? I would imagine they are the easiest to collect at the source, as the particles get bigger they get more mass and would be harder to collect.

When I clean my filter, that fine talcum like powder in the pleats is exactly what I want to collect.

I imagine what you’re saying is true for some equipment, but a lathe practically shoots the dust into the hood. My table saw has pretty poor dust collection, but I’m moving enough air to compensate, I had thought I would end up getting the sawstop blade guard dust collection, but it actually wasn’t needed. I would be covered in dust after using the saw, but since I redid the pipes, hardly any.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View Redoak49's profile

Redoak49

1964 posts in 1456 days


#12 posted 06-01-2015 06:12 PM

The question is how far to go and how do you decide when it is enough??

I would agree that 4” PVC at 40 feet is not good. But at 10-20 feet is it OK?

For a 5 hp cyclone and 6-8” ducting, gates, etc you are looking at $3-4000.

Why stop at 6” and 5 hp? Maybe 8” and 10 hp is better…...

When is it enough? How do you decide? I am not being sarcastic but unless you get some expensive particle measuring equipment how do you know how much.

I watch the air in the shop and on things in the shop. I use a HEPA vac on Sanders and other things that make fine dust. I have an air cleaner that is used when appropriate.

In most cases people will do as much as they can afford to do.

View AZWoody's profile

AZWoody

700 posts in 692 days


#13 posted 06-01-2015 06:51 PM


I think the main thing that he s saying is that most dust collectors, as designed do not do a good job of pulling the finest dust particles from the source. Even if you have a .5 micron filter, the system doesn t have the capacity to collect it at the machine for the filters to be of use.

In most cases, it takes a 12”+ impeller coupled with a 3-5hp motor to be able to give the airflow needed to get the finest of the dust particles that a woodworking machine produces. Those are the ones that can t be seen but are now being blamed for many health related issues.

It sucks, because it s expensive to really do it right. I m in the process of redoing completely my dust collection as I had 4” pipe on 40 runs and yeah, it looked like it was doing a good job but if you really started to look at the air quality with a light, it would leave behind much more than I noticed before.
Then, I started getting nosebleeds the evening or next morning after working in the woodshop.

That was the impetus to really go and put the money down to get this down right.
- AZWoody

I just redid our system 2 months back and I m gauging it off of the dust from my wife s lathe. I measured 300+CFM at the small hood by her lathe. She uses the lathe for hours at a time and it is the major dust producer, so it was the gauge as to whether the system was working well.

So even though I see a cloud flying like smoke into a vacuum, I m not getting the smallest particles? I would imagine they are the easiest to collect at the source, as the particles get bigger they get more mass and would be harder to collect.

When I clean my filter, that fine talcum like powder in the pleats is exactly what I want to collect.

I imagine what you re saying is true for some equipment, but a lathe practically shoots the dust into the hood. My table saw has pretty poor dust collection, but I m moving enough air to compensate, I had thought I would end up getting the sawstop blade guard dust collection, but it actually wasn t needed. I would be covered in dust after using the saw, but since I redid the pipes, hardly any.

- RobS888

I thought the same thing about larger particles being harder to get but they really do get picked up easier than the finest particles.
The best way to see, without needing any expensive particle meter is to shut the lights off at night and use a flashlight and then you can see what’s suspended in the air.

As for the lathe though, I really have never used one so have no experience with them. What I do have is some drum sanders, which obviously are massive producers of dust, an 8” jointer with a spiral head which I can tell you the largest pieces get picked up easier than the smaller ones, a 13 and 20 inch planer and those do the same. I think maybe the surface area of the larger pieces make them easier to get picked up? I really don’t have the background to know the answers to it but I’m sure there is a reason.

For a lathe, I would assume it’s all in the placement like Redoak said for how it’s picked up.

View AZWoody's profile

AZWoody

700 posts in 692 days


#14 posted 06-01-2015 07:01 PM



The question is how far to go and how do you decide when it is enough??

I would agree that 4” PVC at 40 feet is not good. But at 10-20 feet is it OK?

For a 5 hp cyclone and 6-8” ducting, gates, etc you are looking at $3-4000.

Why stop at 6” and 5 hp? Maybe 8” and 10 hp is better…...

When is it enough? How do you decide? I am not being sarcastic but unless you get some expensive particle measuring equipment how do you know how much.

I watch the air in the shop and on things in the shop. I use a HEPA vac on Sanders and other things that make fine dust. I have an air cleaner that is used when appropriate.

In most cases people will do as much as they can afford to do.

- Redoak49

If you have an impeller and motor to match it, then sure you can go 8-10 but that’s more for using multiple machines at once. Where does it end? By matching the size of motor, impeller and ducting that fits the work you do.

To gauge the quality of the air, you can have someone come and test the air but to me that’s kind of overkill.
No need for expensive meters, just turn off your lights at night, after using your equipment and use a flashlight and then you can see what’s in the air floating around. Remember though, the human eye can see something in the air that’s 25 microns. When you’re talking about dust collection in the .5 micron range, that’s a lot that you’re not seeing. That’s what we’re talking about when it comes to the fine particles that usually escape the dust collection system and are floating through the air.

There’s no right or wrong. It’s a choice and what’s appropriate for you. I know for me, what I was doing, with the 4” piping was leaving enough in the air to cause me to get nosebleeds immediately after and up to the next morning.

As for 4” runs, I did a test on air velocity. At 40 feet, I had a 25% reduction in air flow from my machines that were at 15”. That’s mostly due to the friction in the pipe as I measured right at my blast gate that came off the pipe and not through any hose that would go to the machine.

In the end, affordability always comes into play. One thing, I think we all know is that if we were to do everything exactly the way it should be, it’s going to be more expensive than most of us could afford so we all just make do with what we have and go from there.

View jgt1942's profile

jgt1942

138 posts in 1356 days


#15 posted 05-04-2016 08:53 PM

Much thanks for all the replies, just to give a quick update.
Progress has been almost zero but quickly moving up in priority. Lately I’ve been turning a LOT of very dry Mesquite and the dust – gee wiz – has been hell.
My first effort will be to install a curtain around the lathe area and an air cleaner hanging from the ceiling in the curtained area. A friend did something similar and has had very good results.

rwe2156 – ref “Also, I would do some checking on the separator you are using. I’ve heard they aren’t the best way to go.” I suspect that your sources really don’t know what they are talking about. The Thien baffle will extract about 97% of the dust. Nobody does any better. I’ve had my setup almost two years and the bottom bag has a bit of dust in it mainly because I’ve overfilled the Brute can a few times. The over fill can be easily seen through the Plexiglas I used as the wall on my Thien. On the to-do list is to install a sensor that will shut off the DC when the Brute is full but I have too many projects and not enough money, this this is still on the to-do list.

I’ve started some plans to put a permeate DC in one corner of my garage. For my layout this works best for me.
A friend that finished his DC collection gave me his leftover metal pipe thus I may have a combination of metal and plastic.

-- JohnT

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