# DC plumbing questions



## laldog3 (Mar 20, 2011)

I've got a H.F. 2HP dust collector that I'm looking to improve. I'm really not satisfied with the performance of the 4" piping, so I'm contemplating changing the hoses, etc.

A couple of questions:

If the outlets (and inlets) are 5", will I really see any performance gains upgrading to 6" piping? (Won't the 5" opening at the machine restrict the flow and negate any gains?

Will using a small (18") length of flex hose REALLY cause a big drop in performance? Given my shop layout and blower placement, it would be tough to connect my ducting using solid 45's or 90's. Thoughts?

Thanks in advance


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## dbhost (Jan 28, 2008)

I have the HF 2HP DC, and here is my take on it...

#1. If you are still using the bag filter, stop using it NOW. It is a huge bottleneck and can't filter fine enough, so it is basically a dust pump putting the most dangerous dust up where you can breathe it in more easily. Upgrade to a MERV 15 canister filter like a Wynn 35a or similar. There are cheaper ones out there, I just can't name them right now.
#2. Central Machinery chose the most insane impeller size for this machine. Upgrade to either a RIkon (expensive) or Wen (cheap) 12" impeller. That is when they come back in stock... 
#3. If you have a pre separator, that is a HUGE bottleneck as well air flow wise. You might want to consider using a Neutral vane, and / or a Thien baffle in the separator ring of thedust collector.
#4. Airflow is like cars on a road. The smoother, less bumpy, and less curvy the road, the faster the cars can go. The smoother, less bumpy, and fewer tight turns ducting makes the faster dust laden air can go.
#5. There are conflicting reports of whether or not a HF 2HP dust collector can support 6" ductwork. Right now I am running 5" until I split off to dual 4" mains. This allows me to pull from top and bottom of my table saw, router table etc... VERY well. I believe with the 12" impeller mod, it SHOULD be able to support 6" duct work, but it would be just by a razor thin margin. IF You insist on upsizing from the 4", your best bet might just be 5". Sadly 5" is hard to come by, and nothing has 5" ports so there is that...
#6. IF you can manage it, the least ridged flex hose you can have in there, the better, every single bump in the hose reduces your air speed just a bit, and those just a bits add up.
#7. If you have one piece 90 degree bends in your pipe, STOP, cut them out, and replace them with 2 45 degree bends with a stub of pipe, or better yet, 4 22.5 degree elbows with pipe stubs. IF you can set up a jig, and heat up / curve the pipe itself so you end up with a long sweep 90 you would be best off, but most can't do that... Or at least don't want to try...
#8. Minimize your distances from machine, to dust collector. Not really feaseable in many situations, especially if you are just putting your DC where you can make room for it in a typical small shop. 
#9. Are you pulling through reducers to 2.5" ports? That'll choke it down a good bit... Seriously, my band saw came form the factory with one of those, whatever the smaller size shop vac hoses are, sized dust ports. I swapped a secondary 2.5" port into the lower wheel guard, and swapped the OEM dust port with one from a Jet 14", and then connected it up with a 4x2.5 wye and reducer. Kludgey yes, but it works well... 
#10. Even if you had a nice big ClearVue cyclone, you still need an ambient air cleaner, broom, dust pan etc... Woodworking is dusty business..
#11. I mentioned it above, I need to mention it again. Your biggest problem once you deal with filter bag, neutral vane, impeller and insuring not too much ribbed hose, is going to be the machine dust ports. They typically are awful. Spend some time going over dust port improvement ideas for your equipment, sometimes they make sense, sometimes they don't. I can't for example upsize the dust port of my Ryobi AP1301 planer all that easily, but I can partially open a blast gate just past it, to allow for enough air coming through the planer, and the partially open blast gate to allow the dust and shavings once into the system to get, and stay suspended in the air stream...


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## BigCountry79 (Jun 2, 2021)

Thanks for all the details db... dust collection is also something I've been wanting to do better.

On my setup, I also think the blast gates are a limiting factor. I got the cheap plastic ones from powertec,and they do not fully open.


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## BigCountry79 (Jun 2, 2021)

dbhost said:


> There are conflicting reports of whether or not a HF 2HP dust collector can support 6" ductwork. Right now I am running 5" until I split off to dual 4" mains. This allows me to pull from top and bottom of my table saw, router table etc... VERY well. I believe with the 12" impeller mod, it SHOULD be able to support 6" duct work, but it would be just by a razor thin margin. IF You insist on upsizing from the 4", your best bet might just be 5". Sadly 5" is hard to come by, and nothing has 5" ports so there is that...


Where did you find the 5" pipe?


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## Rebelwork (Jan 15, 2012)

You should be able to have 2-4" lines open at once off a 5"


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## dbhost (Jan 28, 2008)

BigCountry79 said:


> Where did you find the 5" pipe?


5" pipe is easy. 5" fittings, not so much. 

Home Depot has 5' segments of 5" Snap Lock sheet metal ducting for $10.98. They are also the cheapest on the adjustable elbows. Where you are going to run into problems with 5" is finding branch wyes. They are tough to come by.

The item that keeps coming up in my searches, yes I am interested in doing this upgrade too, is Imperial Manufacturing GV0989. Price on them seems to average about $30.00 online but the vendors are unkown so may be risky. You may benefit from visiting your home town Ace or True Value hardware store and looking to see if they can do a special order and what kind of price they can get for you...

Otherwise you will need to transition to ABS plastic branch wyes. That is the Wood River 5x5x5 Y Dust Collection Fitting from Amazon for just under $27.00 each.

And if you want to melt your head with information on the subject, read up on Bill Petnz's dust collection research. He is more or less considered the authority on the subject. You may walk away feeling like you need a giant cyclone with giant dust ports, but read deeply into what he is saying, and know you CAN make the HF 2HP DC work it's just going to take some effort...

I'm not saying the 2HP HF DC, especially with an upgraded impeller cannot support 6" ducting. LOTS of folks do it. I am saying it is less than ideal for that motor / blower. They chose well when they put a 5" port on it. They chose poorly when they put a 9.5" impeller in it...


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## WishfulThinking (May 4, 2020)

BigCountry79 said:


> On my setup, I also think the blast gates are a limiting factor. I got the cheap plastic ones from powertec,and they do not fully open.


If this is the case, upgrade to 5" blast gates. I used them on my 4" PVC setup so they don't restrict at all. I have a segment on it in this video: 




Sent from my ELE-L04 using Tapatalk


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## dbhost (Jan 28, 2008)

BigCountry79 said:


> Thanks for all the details db... dust collection is also something I've been wanting to do better.
> 
> On my setup, I also think the blast gates are a limiting factor. I got the cheap plastic ones from powertec,and they do not fully open.


Powertec also has the metal ones that fully open for a fair price. But yeah if you are using a 4" blast gate that does not open fully will reduce performance radically. I'm not sure how complex your system is, but many people are doing well with 4" ducting and 4" blast gates. 5" ducting is a nice upgrade, but sure you could go with 5" blast gates, but you will need to neck down to 4" for most machines, if not 2.5".


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## DrRobert (Apr 27, 2015)

From experience I can tell you 4” ductwork is very restrictive. DC blowers are about moving air, not suction - the opposite of a shop vac.

I am quite sure that blower will perform better with 5-6” ducts. 4” gates/flex to machines.

+1 on filter bag. If possible exhaust outside.

Performance depends on blower, layout, machines, cyclone, filters.


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## dbhost (Jan 28, 2008)

WishfulThinking said:


> If this is the case, upgrade to 5" blast gates. I used them on my 4" PVC setup so they don't restrict at all. I have a segment on it in this video:
> 
> 
> 
> ...


Great video! I need to see if 5" blast gates will fit outside of 4" DVW (thinwall) pipe., I think it would need more Gorilla tape.  

FWIW, I tend to use a single pop rivet at the joints to keep them from coming apart.


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## dbhost (Jan 28, 2008)

DrRobert said:


> From experience I can tell you 4” ductwork is very restrictive. DC blowers are about moving air, not suction - the opposite of a shop vac.
> 
> I am quite sure that blower will perform better with 5-6” ducts. 4” gates/flex to machines.
> 
> ...


For a 2HP blower, yeah 5" is ideal. Not sure if they have enough to keep dust suspended in 6" duct, but like I mentioned above, lots of folks are doing it. I may do it down the road as well. Certainly a LOT easier than 5" to find parts for...


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## Rebelwork (Jan 15, 2012)

I believe I have 4" on the main run and 3" on the machines. All seems to work well..


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## DrRobert (Apr 27, 2015)

Rebelwork said:


> I believe I have 4" on the main run and 3" on the machines. All seems to work well..


Depends on how long the runs are and layout. Every 90 degrades it a lot. It can work in garage not a 50’ long shop.

That s why it’s so hard to recommend without knowing machines & distances, neither of which he’s told us.

A 2HP blower will be choked down by 4”. Doesn’t mean it won’t collect dust. 6” PVC is the best way to go.


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## Rebelwork (Jan 15, 2012)

I can run two pvc 3" pvc pipes and hold a piece of plywood on each. My shop is 600sq ft.


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## dbhost (Jan 28, 2008)

DrRobert said:


> Depends on how long the runs are and layout. Every 90 degrades it a lot. It can work in garage not a 50’ long shop.
> 
> That s why it’s so hard to recommend without knowing machines & distances, neither of which he’s told us. ...


Thoroughly valid points. I am making a BIG assumption here that the OP is a hobbyist setting up a basement, shed, or garage home workshop, typically but not all inclusively limited to a 20x30 space. In my sitaution I am running in an 18x20 space, and depending on my wife, and what we decide to do long term, I may be squeezed into a 10x20 although I would prefer to stay in the garage... I wouldn't even consider a 2HP collector in a 30x30 or larger space... 20x30 is actually pushing it pretty hard. It is pretty comfortable with using it in an 18x20.


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## JamesTinKS (Nov 15, 2012)

I have the HF 2hp dust collector with the original filter bag. I found that most of the dust coming out of the machine was from where the bag(s) are attached to the metal housing. I put a ring of camper seal foam tape around where the band clamps go. Slip the bags over that and clamp them on. As far as I can see I have no dust escaping the machine. Before I added the foam I had dust build up on the walls around the collector. 
M-D Building Products 1-1/4 in. x 30 ft. Camper Seal Foam Tape-02352 - The Home Depot


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## DrRobert (Apr 27, 2015)

JamesTinKS said:


> I have the HF 2hp dust collector with the original filter bag. I found that most of the dust coming out of the machine was from where the bag(s) are attached to the metal housing. I put a ring of camper seal foam tape around where the band clamps go. Slip the bags over that and clamp them on. As far as I can see I have no dust escaping the machine. Before I added the foam I had dust build up on the walls around the collector.
> M-D Building Products 1-1/4 in. x 30 ft. Camper Seal Foam Tape-02352 - The Home Depot


The dangerous dust is the very small particles, the ones you don’t see, no bag is going to filter them out. You have solved a problem there, but if you really should consider replacing the bag with a canister filter. It’s an expense, but worth it. 

Personal experience - bags are notorious for clogging up, greatly degrading performance. They have to be turned inside out and cleaned not a pleasant job! Wear a respirator when doing this, not a dust mask, blow yourself off thoroughly when done. Never wash them. 

As filters, someone mentioned they are terrible, and some are almost useless. The one that came on my wall unit was a laughable synthetic felt thing (I exhaust outside).


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## Rebelwork (Jan 15, 2012)

Small particles is why you have a overhead DC.


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## JamesTinKS (Nov 15, 2012)

I also have a 25" industrial fan with a 4" pleated filter that recirculates the air in my shop a few dozen times an hour that is always running whenever I am making dust.


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## dbhost (Jan 28, 2008)

JamesTinKS said:


> I also have a 25" industrial fan with a 4" pleated filter that recirculates the air in my shop a few dozen times an hour that is always running whenever I am making dust.


I started with a 20" box fan with a 3M Filtrete 20x20 Ultra Allergen MERV 15 filter duct taped to the intake side of the fan I ran on full blast. It worked, it was cheap Only reason to upgrade for me was to free up floor space, and not have a box fan intruding into headroom in the shop should I have opted to ceiling mount the fan... Cheap and effective is good.


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## Rebelwork (Jan 15, 2012)

Any filtering is better than no filters...


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## MorenoF (12 mo ago)

Didn't you think of hiring a specialist plumber to do it for you? There are two levels: journeyman and master plumbers, and you need a master plumber. Replacing the hoses is not as simple as you think, and for everything to work well, it would be better to call a plumber. I also have some knowledge in this field, but I do not hesitate to call a plumber in such cases. You will never know how safe these answers you receive here are, and you need to be careful not to make the problem worse.


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## dbhost (Jan 28, 2008)

MorenoF said:


> Hi sometimes there are cases where filtering is not so necessary and can even be harmful


Okay. Name one of those cases.


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