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Will two HF Dustcollectors double capacity?

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Forum topic by George M posted 10-31-2010 05:41 PM 1309 views 0 times favorited 26 replies Add to Favorites Watch
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George M

118 posts in 2232 days


10-31-2010 05:41 PM

After reading posts on the great deal on Harbor Freight Dust Collectors I picked one up last week. However I do not want to use it as a portable unit. My shop is self contained out back, and I want to install a stationary unit with direct exhaust to the exterior. I already built the Thien separator for it.

However in reading posts it seems like this is not powerful enough to run overhead line. In my shop I would have two overhead lines – one servicing the jointer, table saw and drum sander would be about 15’ overhead. The other would service smaller tools – miter saw, shaper – and be about 25’.

So with the great deal on these DC, if I would connect two together, either in series or parallel, would that in effect double the efficiency?

Thanks

George M

-- George, Parker Colorado


26 replies so far

View Howie's profile

Howie

2656 posts in 2391 days


#1 posted 10-31-2010 05:47 PM

I’m not an expert but I’m not sure “series” will work just by the nature of the way they are made.
For me a more direct solution would be to hook one to the jointer etc and the other separately to the other small tools. Just MHO.

-- Life is good.

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ChunkyC

856 posts in 2722 days


#2 posted 10-31-2010 05:57 PM

Mine lines all run overhead and my HF DC w/ Thien baffle and pre-separator does just fine. Now I’m the only one working in the shop so only one tool is running at a time.

Also, read dbhost’s blogs. He has (or at least he did have) a similar setup as mine. He goes into great detail on his system, what works, what didn’t etc. Tons of good experience there in print waiting to be read.

-- Chunk's Workshop pictures: http://spadfest.rcspads.com/thumbnails.php?album=135

View NBeener's profile

NBeener

4808 posts in 2642 days


#3 posted 10-31-2010 06:01 PM

Quoting Fine Woodworking, from 4/96:

”Add more power by connecting two dust collectors in tandem. You’ll nearly double the force of your system by attaching two units together. Run a hose from the outlet of one blower to the inlet of another. To avoid pressure imbalances, use two identical units.”

-- -- Neil

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ChunkyC

856 posts in 2722 days


#4 posted 10-31-2010 06:05 PM

I just thought of something else. If you planning on venting the unit outside, then you won’t have the pressure drop across the filter which equates to more power! I would definitely hook up what you have and work with it leaving room for the second unit but honestly, I don’t think you’ll need it.

-- Chunk's Workshop pictures: http://spadfest.rcspads.com/thumbnails.php?album=135

View George M's profile

George M

118 posts in 2232 days


#5 posted 10-31-2010 07:46 PM

I’m not an expert but I’m not sure “series” will work just by the nature of the way they are made.
For me a more direct solution would be to hook one to the jointer etc and the other separately to the other small tools. Just MHO

What about in parallel with a Y conecting both to one line?

-- George, Parker Colorado

View George M's profile

George M

118 posts in 2232 days


#6 posted 10-31-2010 07:46 PM

Mine lines all run overhead and my HF DC w/ Thien baffle and pre-separator does just fine. Now I’m the only one working in the shop so only one tool is running at a time.
That’s my situation also. Only one tool at a time.

-- George, Parker Colorado

View Dark_Lightning's profile

Dark_Lightning

2635 posts in 2577 days


#7 posted 10-31-2010 07:59 PM

I’m not sure I agree with FWW’s assessment. If one runs two vacs in parallel with large enough pipe, I’d expect better performance. You’re looking for flow, not pressure drop, really. In parallel, you’d be putting all kinds of guck through the first vac that might clog it up. Guess we’d need a flow dynamicist to verify it- which I’m not.

-- Random Orbital Nailer

View brtech's profile

brtech

906 posts in 2390 days


#8 posted 10-31-2010 08:08 PM

One obvious thing to do is put blast gates on the two overhead lines and close one off when you use the other.

I think you will be okay, although not great with the two overheads. 25’ is long, but not that long. Use 4” pipe, no 90s, just 45s and minimize the use of flex hose. Blast gates on all tools, only open one at a time (plus the idea of one line closed off when the other is in use, and I think it will be okay.

You are upgrading your filter to .5 micron, right?

View George M's profile

George M

118 posts in 2232 days


#9 posted 10-31-2010 08:16 PM

You are upgrading your filter to .5 micron, right?

No – no filter. Since I live on acreage, I will vent directly from impellor to the exterior.
Had planned on blast gates at each machine, but not on each line. Will have to concider that.

-- George, Parker Colorado

View a1Jim's profile

a1Jim

115207 posts in 3045 days


#10 posted 10-31-2010 08:26 PM

I’ve thought of tying two Hf dust collectors together since I have three, but thought I would have each collector on one side of a “Y” vent pipe so that the singe side of the “Y” connector is connected to the main dust collection lines. I wasn’t sure how that would work either.

-- http://artisticwoodstudio.com Custom furniture

View NBeener's profile

NBeener

4808 posts in 2642 days


#11 posted 10-31-2010 08:47 PM

”Guess we’d need a flow dynamicist to verify it- which I’m not.”

... or … somebody who DID stay in a Holiday Inn Express, last night ;-)

Hey, a1Jim: can you try it, and let us know if you notice a difference ??

For people like me … it would be nice to have a $139 upgrade, if it DID give a noticeable boost in air flow !

-- -- Neil

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a1Jim

115207 posts in 3045 days


#12 posted 10-31-2010 08:50 PM

Come on over Neil you I ,Rick (schloemoe) and David can give it a go. :))

-- http://artisticwoodstudio.com Custom furniture

View crank49's profile

crank49

3981 posts in 2439 days


#13 posted 10-31-2010 08:51 PM

You will double the CFM of a given system with two collectors in parallel. No doubt. You will create a negative pressure in your shop which will be a huge burden on your temperature control system. Also, no doubt. You absolutely have to provide “make-up” air to replace what you vent out of the shop. If you live in an area where the outdoor ambient temperature is always in the comfort zone and the humidity is always at a good comfortable level then just leave a window or door open. Otherwise, you have to control the temperature and humidity of all that make-up air, about 1200CFM of it. That’s about the capacity of a 2ton heat pump system.
I don’t know who thinks the HF collectors can’t handle an overhead system. That is simply not true. One unit will handle a 5” diameter duct about 60ft long. Or, 30ft with 3 elbows. Two units would be able to handle two 5” ducts, or one 7” duct. A 5” duct can handle a 2 1/2” and a 4” drop both open at the same time.

I designed dust collection systems for years and I know what I am speaking of here. I also own and use a HF dust collector connected to an overhead duct system.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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a1Jim

115207 posts in 3045 days


#14 posted 10-31-2010 08:56 PM

Ok Crank we need you to join the party too,hech of a drive but I’ll furnish the cookies :))

Thanks for your help

-- http://artisticwoodstudio.com Custom furniture

View NBeener's profile

NBeener

4808 posts in 2642 days


#15 posted 10-31-2010 08:58 PM

Wow.

Thread ender.

[Bows to Crank49…..]

-- -- Neil

showing 1 through 15 of 26 replies

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