# Outlet Hose On Dust Collector



## Mike Burke (Feb 9, 2016)

I have a 2hp Grizzly Dust Collector with a corrugated plastic pipe from the fan housing to the bag holder...like it the photo. Would it be worth the trouble to try and change it to a smooth wall pipe ?

Either a couple elbows and straight section of pipe or smooth wall flex hose.

Do you think it would help with air movement much or even be worth the trouble ?

I do have it wired 220 and a Wynn filter.

Just trying to make it as efficient as possible.


Thanks


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## ryan50hrl (Jun 30, 2012)

Yes it would be an improvement, however it's difficult to determine how much of an improvement and if that's worthwhile. 

If it were me, I'd probably leave it...


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## mat 60 (Jul 9, 2012)

I would leave it also.


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## johnep (Apr 12, 2007)

It would certainly change airflow more to streamline than turbulent. You never see corrugated pipe used as an inlet to an engine.
Mr Bernouli had the answers.
johnep


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## UnisawGuy (Jul 20, 2014)

Leave it. There is nothing that can be done to make that an efficient dust collector. 
Best option: junk it and put in a cyclone.


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## Johnnie_dr (Apr 16, 2016)

Hey Mike,

I have a 2HP Harbor Freight DC, with Wynn Filter and a Thein Baffle I made. I recently reconfigured the whole unit so that the motor/impeller was directly in-line with the inlet to the filter and bag section. Thus having a short-straight 6inch section of the of the same type of pipe.

By doing that, I eliminated the long section of tubing (that you point out), plus eliminated the bend. I saw and felt an immediate improvement in airflow. To do this, I built a wooden frame/rack to bring it all into play.

Sure UniGuy...we'd all love a cyclone, but most of us cannot afford them...

jdr


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## UnisawGuy (Jul 20, 2014)

Johnnie_dr I agree with you that most budgets do not allow a cyclone. 



Johnnie_dr said:


> Sure UniGuy...we'd all love a cyclone, but most of us cannot afford them...
> 
> jdr


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## laxin213 (Jan 25, 2013)

ryan50hrl said:


> Yes it would be an improvement, however it's difficult to determine how much of an improvement and if that's worthwhile.
> 
> If it were me, I'd probably leave it...




Use a wind aneometer to measure the business end of the dust collector before and after the change. You're going to have a measure able improvement and you can measure that in mph and convert to cfpm

Wind Speed Meter - Digital Anemometer with Thermometer https://www.amazon.com/dp/B009YP0BAG/ref=cm_sw_r_cp_awd_D3TexbW56NJ78


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## ryan50hrl (Jun 30, 2012)

But the collector would need to be tested while running with the bags in place, so then how do you hold the meter there?


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## Hammer1 (Aug 1, 2010)

You would spend time and money more wisely by looking at the rest of the collection system, lengths. elbows, gates, etc. The interior of that hose is pretty flat, everything has past the impeller. I have a similar DC with a cloth lower bag, efficiency dropped significantly when I used a plastic bag.


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## Mike Burke (Feb 9, 2016)

> efficiency dropped significantly when I used a plastic bag.


I went with the plastic bag on the bottom. I thought that the cloth bag would let dust out every time you turned on the collector.
So your saying that yours worked better with the cloth bag ?

Mmm.....I might try going back to my cloth bag.


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## woodnthings (Jan 24, 2009)

*air in = air out ?*

The air that gets sucked into the transition fitting is expelled up or down into the filter or the catch bag. If the bag is plastic it will not allow air to escape. I use a cardboard drum on mine, so all the air must escape through the canister filter. The better the filter, the more air can escape. As the fine dust builds up on the inside of the filter, either bag or canister, the efficiency is reduced, but the filtration is increased. The canister have spin paddle on the top to knock off the fine dust before starting the DC.... and if you remember to do this you'll have better results.

Many folks have built separator to remove as much of the fines as possible and that's a great idea, but it takes up additional floor space which is not always available in a home shop. Again it's a trade off.

You tube has a whole bunch of DC modifications:
http://www.youtube.com/results?search_query=modify+harbor+freight+dust+collector

Some of these modifications include wall mounting the blower/motor and eliminating the hose between the transition unit. You may want to consider this IF you don't need the DC to be mobile. My DC's must be mobile, so I can't use this approach.:frown2:


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## laxin213 (Jan 25, 2013)

ryan50hrl said:


> But the collector would need to be tested while running with the bags in place, so then how do you hold the meter there?




Attach a short hose to the end of the dust collector. Use the stock hose and measure the suction at the end, the part you'd use to suck stuff up. Holding everything else constant in the setup, swap the ribbed for smooth hose, and again use the dust collector as you would, with the wind anemometer at the end of the hose to suck up some sawdust. 

When making a systemic change deep inside the dust collector (also think car engine) , best to evaluate overall performance. Think "so I made this change inside, I'll keep all other variables constant, how does this affect the thing it's supposed to do - suck up dust (or produce HP like a car engine). So using the dust collector as intended will give meaningful results.


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## Oneal-Woodworking (Apr 14, 2013)

Mike Burke said:


> I went with the plastic bag on the bottom. I thought that the cloth bag would let dust out every time you turned on the collector.
> So your saying that yours worked better with the cloth bag ?
> 
> Mmm.....I might try going back to my cloth bag.


The reason that efficiency (he likely lost a little bit of suction is what he really means) dropped for that guy is likely because he has a garbage china upper filter bag that is not anywhere near properly sized for his machine and the CFM that he wants to flow. 

When the upper bag is undersized like that the DC will actually use the lower cloth collection bag as a 'filter' bag as well until it fills up to a certain point. (meaning that if it can't push the air out of the top filter bag fast enough - It will push it out the bottom bag as well until the bottom bag gets full)

This is one way the china DC's manage to pull of the CFM numbers that they do with such obviously undersized upper filter bags for their intended application. What they don't tell you in their goofy ads is that as the bottom bag fills up - The CFM goes way down. (because you just lost a third of your usable filter surface material)

That is NOT what you want to be doing if you can help it. 

Since you actually have a nice filter up top that flows (when clean) a lot more air than most any china bag ever will - You can and DO want a non-breathable lower collection bag if you can help it. 

You CAN get and use a lower cloth 'collection' bag that is made of non-breathable fabric but Grizzly is not the place that sells those...


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## Oneal-Woodworking (Apr 14, 2013)

UnisawGuy said:


> Leave it. There is nothing that can be done to make that an efficient dust collector.
> Best option: junk it and put in a cyclone.


The Wynn canister filter the OP added already made it a much more efficient dust collector than what it was to begin with and there is still plenty of room to upgrade what he has even more. 

Not sure where you did your learning about dust collectors but you still have a LOT of learning left to do friend. :smile3:


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## UnisawGuy (Jul 20, 2014)

I know that an efficient dust collection system collects 99.97% of airborne particles 0.3–0.5 microns in size.
I do not know the math and physics to calculate the air velocities, CFM requirement, and ducting size to achieve that efficiency. You are right: I do have a lot to learn.:smile3:



OnealWoodworking said:


> Not sure where you did your learning about dust collectors but you still have a LOT of learning left to do friend. :smile3:


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## Johnnie_dr (Apr 16, 2016)

Hi Mike,

I just joined the forum , so I can't send a detailed message back to you or a picture...yet. But you can see my HF DC setup on my website. 

Go here: http://riodesignltd.com/wordpress/my-shop/ and click through to the slides. You'll see my DC setup. I pulled the motor/impeller unit off of the factory stand and mounted it vertically on a mounting bracket I built outta 4x4 timbers, so it aligns horizontally to the filter/bag and vertically to my thein baffle. Big improvement.!!

You can see a Utube video of similar setup here at StumpyNubs...



Here's a more complex setup using a Super Dust Deputy and HF DC...




Hope that helps...

have fun,
johnnie


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## Oneal-Woodworking (Apr 14, 2013)

woodnthings said:


> The air that gets sucked into the transition fitting is expelled up or down into the filter or the catch bag. If the bag is plastic it will not allow air to escape. I use a cardboard drum on mine, so all the air must escape through the canister filter. *The better the filter, the more air can escape. As the fine dust builds up on the inside of the filter, either bag or canister, the efficiency is reduced, but the filtration is increased.* *The canister have spin paddle on the top to knock off the fine dust before starting the DC.... and if you remember to do this you'll have better results.*


You nailed it as far as the canister filters are concerned in my opinion.

:thumbsup:


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## Mike Burke (Feb 9, 2016)

Well resurrecting an Old thread. I have bought a Super Dust Deputy for my system.
I am at a cross roads on how to hook the SDD to my system.
I know that just running flex hose from the SDD top to the inlet to my collector is not going to be that effecient.
I could run hard duct with adjustable elbows instead of flex hose...with would/might be a little better.

https://www.oneida-air.com/inventoryD.asp?item_no=AXD002030A&CatId={17F46883-40BB-471E-982F-E5F28583241B}

I could rebuild everything and mount the motor on top of the SDD and redo the Wynn filter setup. I have seen some systems like that this

http://www.diytyler.com/2016/12/16/2-stage-harbor-freight-dust-collector-hack/

I am limited to the height in my basement shop to 70 ". I don't know if I could design something that would be ok on the height.

Or...I could consider trying to sell everything and look at already made Cyclone's

Any suggestions/insights/tips ?? Thanks 

ps. I just have a small shop in my basement and run one machine at a time. table saw, router table, jointer
but its nice to have it hooked up so I don't have to move stuff around.


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## Mike Burke (Feb 9, 2016)

Thinking about what I could do with my system.
Here are a few ideas I have to modify this....and a question or two

Take the motor and rotate it 90 deg to the right and raise it so I can run direct into the collector body.

Shorten the Plastic catch bag to 1/2 of what it is now..so I can lower the filter/bag assembly so the hard duct to the SDD is shorter.

(Is it necessary to have a large plastic bag if I'm going to use a SDD ?) I do have a Plastic bag under the cloth bag. 

Run hard duct pipe for my SDD to the impeller body hookup with adjustable elbows..Short as possible.


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## ducbsa (Jul 6, 2014)

johnep34 said:


> You never see corrugated pipe used as an inlet to an engine.
> 
> johnep


They are pretty usual from the air filter to the throttle body on modern cars. Not on my '31 Ford or '66 Triumph!


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## Lenny Howard (Mar 25, 2016)

Mike, you did say you have the wynn filter, right? I am working on setting up a very similar system. I have mounted the HF collector on the wall so that the inlet is directly over the Super Dust Deputy. I found a 6' to 5" galv. reducer with both ends crimped. The 6" end fit into the sdd but I had to cut a portion off the 5' end (about 5/8") then flatten out the crimping with a hammer. it is now a pretty good fit over the stock inlet on the HF. I may eventually remove that inlet and cut in a 6" one, if and when I convert the impeller to the larger Rikon one. 
I see no reason you can't use a smaller plastic bag under the cone/Wynn filter. The SDD should catch all but a very small amount of the fine dust. I don't really understand what or why you are using the cloth bag for at this point? 
One thing they do recommend is to have at least 5' of straight run coming into the SDD. I am using 5" metal duct and for me and my small space this is going to be a problem. Still a work in progress. Good luck with yours! 

Lenny


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## Lenny Howard (Mar 25, 2016)

I really need to clean my shop before I can go much further but with the temperatures finally in the 40's I couldn't wait to get a start on my setup.


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## Mike Burke (Feb 9, 2016)

Thanks Lenny, I rebuilt my system I went with 6" inlet on my blower...I cut a 6" hole in the metal and used a 6" to 6" drop in. I used 5" snap lock pipe for my whole system. It moves a LOT of air now. Works Great !!!


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