# Difference between a vac and DC system?



## Sherif (Sep 6, 2011)

Hi Guys,

I almost read all the DC threads here and it appears most favor the HF DC system.

I am just curious, if a regular vac has more power than a DC system, why doent i have same or better suction power than the DC system?

I modified a regular home vaccum cleaner (2000 watts) and it does not suck the heavy shavings, although when i put my hand on the hose, it sucks very powerfully. I used 2.5 inch hoses all the way.:blink:

Can anyone please explain.

Thanks


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## woodnthings (Jan 24, 2009)

*shop vac "power" is overrated*

Those 6 HP shop vacs ratings are not realistic. What is important is air flow and velocity. A shop vac has a high velocity air flow in a smaller diameter hose. The DC unit has a lower velocity but much greater volume of air flow.
The woodshop machines generate 2 types of waste material, dust and chips. A planer or jointer will generate so many chips in a typical session that a shop vac will need to be emptied several times. It may also experience a clog because of the nature of the shavings. A DC unit will easily collect that volume of chips. 

I use my shop vac on the router table, bandsaw, and the blade cover on my table saw where the dust is finer, and in smaller quantities. I use the DC below the cabinet on the table saw, and on the jointer and planer. I have a dual drum sander which makes more dust than a shop vac could keep up with. It also requires the larger area of filter and a larger suction hose on a DC. I move the DC and the 4" hose from machine to machine rather than have a whole shop piped with blast gates and so forth. I have a quick connect system which takes less than 10 seconds to attach or remove. 

Shop vac specs:
http://www.shopvac.ca/specifications/blower_vac_series.asp

A typical DC specifications:
http://www.grizzly.com/outlet/2HP-Canister-Dust-Collector/G0548Z


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## Fred Hargis (Apr 28, 2012)

Yep, what woodnthings said. They are completely different tools for different purposes. Both are absolutely necessary for a shop (IMHO).


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## jigs-n-fixtures (Apr 28, 2012)

The hp ratings are generated by the same type of misapplication of an equation as is done with routers. 

There is an equation to find hp given flow pressure and volume. The two measurements are supposed to happen at the same time. The manufacturers measure them separately. Volume at free flow, and pressure at no flow. And all of a sudden you get hp ratings that are physically impossible.

Sent from my iPhone using Wood Forum


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## Sherif (Sep 6, 2011)

Thanks all.

Could you please recommend me something lower than the hf dc, it is too big. I have a mitre saw, circular saw, sanders, planning for a router, and drill press.

What rating should i look for? Cfm or hp? And how much? I would want to connect all tools to a dc network, but will use them one tool at a time by controlling gate at each tool.

Finally, cant i use 2.5 inch hose? Those 4 inch hoses are bulky. I am using one of my flat room as my workshop :icon_cool:

Thanks


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## woodnthings (Jan 24, 2009)

*Ah Ha, added information!*



Sherif said:


> Thanks all.
> 
> Could you please recommend me something lower than the hf dc, it is too big.* I have a mitre saw, circular saw, sanders, planning for a router, and drill press.*
> 
> ...


For your current purposes a good shop vac, quiet like a Rigid, will work. I wouldn't bother with a "network" of piping/hoses.
Just make a quick attach fitting at the end of each machine's hose and then attach the centrally located shop vac to the desired machine. Oh, I suppose you could make a center hub, with 4 or 6 outlets with a permanent connection if that would work better. But a mobile shop vac with a short connector hose will take up less floor space and fewer hoses to trip over. You could run 2" PVC around the room with some "Y"s and gates, but for your present tool collection, kinda of a waste in my opinion. That network of piping is better saved for a more complete DC system with the larger unit.

Something like this which is sorta inbetween may work for you also:
http://www.ebay.com/itm/Heavy-Duty-...959?pt=LH_DefaultDomain_0&hash=item337988ddff


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## jschaben (Apr 1, 2010)

Hi Sherif - I have almost the same situation. I have a small table saw, router table, miter saw, small bandsaw and drill press. I also have most of my hand held power tools set up for dust collection. Obviously a basement shop and I have no space, neither physically nor electically for a full size dust collector
I use a 6.5 HP (advertised HP) shop vac and a dust deputy. The HP rating for the Shop-vac isn't important. I wanted something that would pull about 200 CFM of free air through a 2½" hose and generate about 60" of standing pressure at 0 air flow. I also wanted it in a small package which turned out to be this one. 
http://www.shopvacstore.com/product/hardware-store-ultra-pro-wetdryblower-vac-12-gal65-hp

I coupled that with a Dust Deputy to help manage filter bag usage which is found here:
Amazon.com: Oneida Molded DIY Dust Deputy Cyclone: Home Improvement

I then built a cart for it and it just rolls around and plugs into whatever I happen to be using. All the tools have adapters of one type or another to plug that hose into.
:smile:


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