# Shopvac hose diameter to cfm



## thudson (Feb 2, 2011)

My ridgid 5.0hp shopvac has a 1 7/8" hose. I recently purchased two extension wands and floor brush adapter so that i could use this to easily collect the sawdust off the floor. I was expecting to get alot more suction than i actually got. I was wondering if it would be more benficial for me to get a adapter so that i could connect a 1 1/4" hose to my shopvac, of course i would also have to get two more extension wands and the floor brush in 1 1/4" too. Would the smaller diameter hose result in a more powerful floor brush? Would i get more suction Any opinions?


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## MGW (Jan 25, 2011)

Maybe a little. The old fluid equation may apply here. Q=VA. Q = the flow cfm. V= velocity ft/min. A = area ft^2. You loose a lot when you add on hoses as well. Pipe roughness, pulling over a longer distance, etc.


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## Rick Mathison (Jun 16, 2010)

If all you have on there is one hose and the extensions it should be just fine. When was the last time you cleaned the filter?

Rick


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## thegrgyle (Jan 11, 2011)

*just a thought....*

actually, if you cut the hose diameter size down, you will lose suction, and cfm. Also, since the hose is corrugated (not smooth walled), that cuts down on air flow as well. You would be better off trying to use solid pipe (PVC) as much as you can, and then transitioning into the other corrugated hose.

Also, you might want to make some sort of separator to put in between your vac and the dust you are trying to collect.... then you don't have to be cleaning your filter that often.

a popular separator is the thein cyclone....

http://www.cgallery.com/jpthien/cy.htm

or just search online for it.


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## dodgeboy77 (Mar 18, 2009)

You may have one of the 'Black Friday' $29 specials. About the only drawback is that they have 1 7/8" hose instead of the 2 1/2" hose the more expensive models have. You can buy bigger hose to fit this vac at either HD or Sears for about $20. I think running bigger hose would help your situation, not smaller.

Here's another post about a similar situation: http://www.woodworkingtalk.com/f12/cheap-simple-ridgid-shop-vac-hose-adapter-21242/

Bill


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## GeorgeC (Jul 30, 2008)

thegrgyle said:


> actually, if you cut the hose diameter size down, you will lose suction, and cfm. Also, since the hose is corrugated (not smooth walled), that cuts down on air flow as well. You would be better off trying to use solid pipe (PVC) as much as you can, and then transitioning into the other corrugated hose.
> 
> Also, you might want to make some sort of separator to put in between your vac and the dust you are trying to collect.... then you don't have to be cleaning your filter that often.
> 
> ...


Correct. Do not change anything.

g


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## MGW (Jan 25, 2011)

Filter means a lot. I changed mine and it was a different machine. Now I stop and tap it clean, I need one of those cyclone attachamathings.


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## thudson (Feb 2, 2011)

*...*

I think im just going to stick with what i got. My only question is as far as filters and separators go. I cut up a thin bed sheet and rubberbanded it around my fiter so that sawdust doesnt clog it it up. Is that a reliable means of filtration for fine particles? Would swithing to a 2 1/2" hose benefit me?


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## Fishbucket (Aug 18, 2010)

Take the bed sheet off and try cleaning or ionstalling a new proper filter. You should see a change. :yes:
The bed sheet restricts the volume of air too much, plus it will clog quickly. a "filter" has pleats that create surface area, thus allowing more volume of air to pass.


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## thegrgyle (Jan 11, 2011)

thudson said:


> I think im just going to stick with what i got. My only question is as far as filters and separators go. I cut up a thin bed sheet and rubberbanded it around my fiter so that sawdust doesnt clog it it up. Is that a reliable means of filtration for fine particles? Would swithing to a 2 1/2" hose benefit me?


I actually saw a "trick" that some one used on a shop vac, and that was to wrap the filter with an old pair of pantyhose.  It is porous enough to "filter" out the bigger dust, and makes it alot easier to clean. :thumbsup: I haven't tried it yet, mostly because I am waiting on mama to hook me up with a pair. :huh: she doesn't wear them that often. :no: If you do try this, let me know how it worked.:icon_smile:


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## msmccuistion (Sep 18, 2010)

I've been using a CleanStream filter I found at Lowes. It has some kind of coating on it that helps it shed dust. Most of the time I don't even have to use the compressor to blow it out. It was a little expensive at about $30 but so far it has been well worth it. I'm using it on a Craftsman vac but the box said it was for Rigid also. It's made a huge difference in the amount of suction I get and I don't have to take everything apart to clean the filter nearly as often.


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## thudson (Feb 2, 2011)

thegrgyle said:


> I actually saw a "trick" that some one used on a shop vac, and that was to wrap the filter with an old pair of pantyhose.  It is porous enough to "filter" out the bigger dust, and makes it alot easier to clean. :thumbsup: I haven't tried it yet, mostly because I am waiting on mama to hook me up with a pair. :huh: she doesn't wear them that often. :no: If you do try this, let me know how it worked.:icon_smile:


Im going to stick with the bed sheet a little longer because right now it is workin for me but when it comes time to empty and clean my shopvac out ill try out the pantyhose trick. Ill definitely let you know how it works out.


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## TS3660 (Mar 4, 2008)

Going to a bigger diameter hose won't help unless the intake at the mouth of the vac itself is bigger than your present hose. You can only suck according to the smallest diameter in the line. You may be able to go to an autoparts store and get a foam air filter wrap that would fit your filter. That would be better than the sheet or pany hose.


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## CaptRandy (Jan 27, 2011)

On a side note, use old medicine bottles (like from vitamins)for linking hoses. Cut off both ends with a hacksaw and fit to size.


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## SteveEl (Sep 7, 2010)

thudson said:


> Im going to stick with the bed sheet a little longer


T, I noticed you only just joined us, so you might have missed my post about a good sale on real dust collectors. Do you know about stationary "floor sweeps"? 
http://www.woodworkingtalk.com/f32/139-coupon-2hp-dc-harbor-freight-machine-22460/

This isn't meant to diss shop vacs, I'm doing exactly like you right now. The nylon seemed to help, or at least it makes me feel good. I give the vac and filter at least a crude cleaning after every couple of shop days of even light use, or whenever I hear the motor change its tune or get hot.

Best
Steve El


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## TS3660 (Mar 4, 2008)

My shop vac is unlike any I have ever seen and I can't find another one like it. It is a vac from a bead blaster made by Dayton. Looks just like your normal shop vac but inside, there is a metal frame that sits inside of a cloth bag that covers the entire diameter of the vac. Imagine a lampshade made out of a metal skeleton-like frame. You put this cloth bag in the vac that is the diameter of the vac and about 1/2 the depth. The bag has a plastic rim so it sits on top of the vac rim. Then you put this frame in there (kind of an upside down lamp shade) on top of the bag. The frame and bag sit on the rim of the vac can. The intake to the vac is under the bag. So, the entire bag is the filter. It works like the dickens and I don't know why they are not all made like that. I can still put a regular filter on the bottom of the motor, and I do, but it never gets anything on it. So, when the bag gets clogged, I simply take it outside and beat it against a tree (don't tell the tree huggers) and put it back in the vac.


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## SteveEl (Sep 7, 2010)

TS3660 said:


> when the bag gets clogged, I simply take it outside and beat it against a tree (don't tell the tree huggers)


so THAT'S why my pals at the Sierra Club meeting had dusty shirtfronts....


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