Static Pressure... how important is it?

[kartracer63]

Hi ShopBotters,

Kind of a follow-up qusetion regarding dust collection.

I'm shopping for a new dust collector. I'm looking at 1½ hp 1100 cfm dust collectors with canister filters.

I can buy a JET with the canister filter and their new Vortex Cone for $699.00 (free freight)
http://jettools.com/us/manufacturing/en/product.html?node=4524&product=377066
--- or ---

Delta is running a special on their 1½ hp dust collector. Their 1½ hp is $499.00 (free freight) normally with a bag, but promo is a free upgrade to their canister filter.
http://www.deltamachinery.com/products/dust-management/item/50-786

The biggest difference I can see between the two dust collectors is the the "Static Pressure". The JET's static pressure is rated at 10½" of water, and the Delta's static pressure is rated at 8" of water.

In layman's terms please... what is "Static Pressure", and how does it relate to dust collectors? Is the lower static pressure on the Delta a deal breaker?

Thanks again! You guys are such a big help.

[steve_g]

http://www.oneida-air.com/Images/Static/3hp-super-curve.jpg

to get a true picture, you want to know CFM at a particular S.P. the best is to see the full curve... how fast does the CFM fall off as the filter gets plugged

SG

[kartracer63]

Thanks Steve. But, I did say layman's terms. None of that makes any sense to me.

[Ajcoholic]

If I were you, and I know I am not, I wouldnt buy any collector without a cyclone separator.

A decently designed Cyclone will save you time, which is $$, and also keep your filters clean, and your air cleaner.

Something like one of the Oneida systems with a cyclone would be my choice for a smaller sized collector.

If youre looking at 1.5HP systems... look at this:

http://www.oneida-air.com/inventoryD.asp?item_no=XXP010100H&CatId={B75F8739-54DE-47CA-A8FE-4FE9AEFDCC1C}

AJC

[steve_g]

I agree 100% with Andrew!

SG

[Ajcoholic]

Thanks Steve. But, I did say layman's terms. None of that makes any sense to me.

Static pressure is the amount of resistance measured in inches of water, produced when air is moves through an object like duct work. The higher the static pressure or resistance, the more energy it takes to move air through the object.

[Ajcoholic]

Also, with a cyclone you can use a drum/barrel to catch your chips - and do away with those blasted plastic bags!

And, since the cyclone and bin are on the suction side of the fan, you dont need to worry about the dust blowing out of every nook and crack that you dont clamp tight. The lid wants to suck down onto the drum.

Once you use a good quality dust collector, with a cyclone separator and a good filter, you will NEVER regret spending a little more money.

Also the Oneida stuff isnt imported from China, it is made in the USA. But, as with every other tool, you do really get what you pay for. And they stand behind their stuff 110%.

AJC

[Bob Eustace]

Hi Eric

We have the 2hp version of the Jet unit you are thinking about. The internet is pretty useless on DC comparative reviews and Jet is pathetic in this area as well. We bought ours after seeing it working on a mates Bot. We got the 2hp unit though. We decided to upgrade our DC after starting to get crook breathing wise! Reckon breathing is a pretty important function!

Suggest you have a read of what this guy has to say - it was a real eye opener to us and we instantly moved our DC outside the workshop.


http://billpentz.com/woodworking/cyclone/Index.cfm

Bob & Chrissy in Oz

[Ajcoholic]

Hi Eric

We have the 2hp version of the Jet unit you are thinking about. The internet is pretty useless on DC comparative reviews and Jet is pathetic in this area as well. We bought ours after seeing it working on a mates Bot. We got the 2hp unit though. We decided to upgrade our DC after starting to get crook breathing wise! Reckon breathing is a pretty important function!

Suggest you have a read of what this guy has to say - it was a real eye opener to us and we instantly moved our DC outside the workshop.


http://billpentz.com/woodworking/cyclone/Index.cfm

Bob & Chrissy in Oz

Bob,
That is why a cyclone, and a HEPA filter on the other side of the fan are the two best things you can do to separate dust, and prevent it from being blown around in the shop.

I run a larger (7.5 HP) system in my shop, with a large Oneida cyclone in front of the fan/filter system. The cyclone stops almost ALL the dust, even fine sanding dust from my 36" wide belt sander - from getting to the filter bags. Everything drops out of the cylcone into the collection bin.

There have been tests on the smaller systems, and a cyclone combined with a HEPA rated filter is the best you can get.

AJC

[feinddj]

Andrew is spot on. I run a Onieda Dust Gorilla, 1.5 hp for my bot. I empty the drum once a week or so. I blow out the filter and empty the catch bin for the super fine dust once a month and its never been much in there.

There is one other benefit of a cyclone, the large chips and almost all the dust drops into the drum BEFORE it goes through the impeller. This means the blades can be tighter, moving more air and not getting damaged by chips and chunks that get drawn into the DC. It also relates to less noise.

David

[kubotaman]

Eric, I have the same unit as you are looking at except it does not have the cyclone. This unit is older so that is why there is no cyclone. The filter on top is nothing but a hassle to clean since a lot of the dust plugs it. I have to clean it every time I empty the bag! To me it doesn't have enough power to do what I expect it to do. I always have dust that will excape the dust foot. If I were you the least I would look at is a 2 hp unit but it absolutely has to have a cyclone! i would also look at all the different brands out there and of course I would definitely buy USA made goods if at all possible. Do not just go by price. I think you may be dissapointed if that is all you are measuring your "pick" by. A little more money spent will definitely save you money in the long run if you choose something a little less money.

[Bob Eustace]

Bob,
That is why a cyclone, and a HEPA filter on the other side of the fan are the two best things you can do to separate dust, and prevent it from being blown around in the shop.

I run a larger (7.5 HP) system in my shop, with a large Oneida cyclone in front of the fan/filter system. The cyclone stops almost ALL the dust, even fine sanding dust from my 36" wide belt sander - from getting to the filter bags. Everything drops out of the cylcone into the collection bin.

There have been tests on the smaller systems, and a cyclone combined with a HEPA rated filter is the best you can get.

AJC

Hi Andrew

The research we did seemed to say that going thru a cyclone first created resistance in limited horse power systems. The Jet Vortex is a different form of cyclone yet does exactly the same thing. It does however really work. Stick a bucket of shavings on the floor and you will get a bucket back in the vortex bit. I reckon having it outside though is the safest system. The massive drawback though in cold climates is you lose great gobs of heat. We do use a small Oneida on a shopvac for general clean up. Works great even though its a **** vac!
Used your great suggestion on the Z axis with flexible tube. Worked a treat, so a million thanks.

Bob

[Bob Eustace]

Eric, I have the same unit as you are looking at except it does not have the cyclone. This unit is older so that is why there is no cyclone. The filter on top is nothing but a hassle to clean since a lot of the dust plugs it. I have to clean it every time I empty the bag! To me it doesn't have enough power to do what I expect it to do. I always have dust that will excape the dust foot. If I were you the least I would look at is a 2 hp unit but it absolutely has to have a cyclone! i would also look at all the different brands out there and of course I would definitely buy USA made goods if at all possible. Do not just go by price. I think you may be dissapointed if that is all you are measuring your "pick" by. A little more money spent will definitely save you money in the long run if you choose something a little less money.

Hi Darryl

There has been enormous advances made by Jet. Current models have a "paddle" in the cannister which is a breeze to move externally just with your fingers. I can assure you that you can stick your head up inside the cannister and there is no dust. The vortex idea is brilliantly simple and can be retrofitted to your unit. Its a sort of witches hat. I tooooo was very sceptical until I saw it working. The newer units are way quieter (have a DB meter as we are in a noise sensitive area).

Bob

[kubotaman]

Bob I also have the so called paddle in my upper filter. In my case it is just about useless in cleaning the filter since so much dust gets located there. I am sure there have been a lot of advances in this unit since I bought mine. My point is that I would still go for a more powerful unit versus a 1.5 horsepower since I feel it is still a little under powered for my Bot. Yes i realize i can purchase the new cyclone and add it to mine but it costs about half as much as a new unit. I felt it was a little over priced.

[steve_g]

A note of caution regarding the Oneida 3hp unit...
In order to get my unit in my eight foot ceiling shop, I was limited to a 35 gallon chip barrel. When running the Bot while using a surface planer, you can fill 35 gal. in a remarkably short time. With the barrel, Cyclone, filter, ductwork and hoses all completely filled with chips, it still sucks remarkably well... and takes more than a day to set right!

Steve

[blackhawk]

Eric - As Andrew mentioned, the static pressure rating of a unit tells you how much airflow resistance that it can overcome. The higher the static pressure rating the better. You need enough static pressure to overcome the airflow losses in your collection system. There are charts that give you static pressure losses for ductwork. There is a certain loss for a 90 degree elbow, a certain loss for flexible hose, a certain loss for straight pipe, etc. You have to add all these losses up and be sure that your chip collector has at least that much static pressure rating + some fudge factor.

Static pressure is similar to the head rating on a water pump. If your well is 100ft deep, you need a pump with a 100 ft head rating, probably 120 ft to be safe. It is just overkill to buy a pump with a 500 ft head rating.

[steve_g]

It is just overkill to buy a pump with a 500 ft head rating.

Unless you are planning for future expansion...

SG

[Ajcoholic]

Hi Andrew

The research we did seemed to say that going thru a cyclone first created resistance in limited horse power systems. The Jet Vortex is a different form of cyclone yet does exactly the same thing. It does however really work. Stick a bucket of shavings on the floor and you will get a bucket back in the vortex bit. I reckon having it outside though is the safest system. The massive drawback though in cold climates is you lose great gobs of heat. We do use a small Oneida on a shopvac for general clean up. Works great even though its a **** vac!
Used your great suggestion on the Z axis with flexible tube. Worked a treat, so a million thanks.

Bob

Bob,
That is the problem in my neck of the woods.... for 6 months the temps are well below zero, and it costs enough to heat the shop as it is... putting the DC outside, means a lot of heat loss!

For mine, I had to have a separate area built with a 12' high ceiling as the 10' 6" ceiling height in my shop was not enough for the unit.

As it stands my cyclone JUST clears the ceiling... and allows my waste bin to fit under. I have a large bin on wheels I slide under the cylcone, instead of a barrel.
http://i83.photobucket.com/albums/j307/ajcoholic/IMG_0782-1.jpg
AJC

[genek]

I run a jds cyclone 3 hp i empty a fifty five gallon drum every day... I have a large filter,,, the filter get stopped up if you do not clean it once a week. Would not have anything but cyclone... Have had all types but the jds beats all hands down... It is model number 3000k