Vacuum "pressure" needed for dust collection

[donframbach]

Hello all, I am currently using a Fein shop vacuum connected to my dust collector and it is working well. However, the Fein vacuum only holds a few gallons of dust and I'm a little concerned about running the vacuum for hours at a time. I am considering an Oneida 1.5 hp system but wonder if it will work. I understand that the static pressure from the Fein is about 90 inches of water and the volume is about 100 cubic feet/minute. The Oneida dust collector can draw a larger volume of several hundred cubicfeet/minute but at a much lower static pressure of only several inches of water. Anyone have experience with an Oneida or other brand dust collector connected to the ShopBot dust collection system?

TIA Don Frambach

[rgbrown@itexas.net]

Don,

Dust collection is an art/science. There are essentially three factors: pressure, velocity and volume. They are inner-related. A volume collection system like the Onedia needs a larger hose and the high volume keeps the velocity up so the chips get to the collector. The Fein uses higher (actually less pressure) vacuum and a smaller hose - the velocity stays up, the chips go to the container.

Perhaps your first "trick" should be to put a collection drum between the vacuum and the router. That will allow most of the dust and chips to drop out and the cleaning of the vacuum will be less often.

The Fein has an external cooling fan (if I remember right) and can be used for extended periods without problem.

There was a group of posts on dust collection with links to external sites a week or two back. The links had a lot of good information. One could build a lot of a dust-collection system with a ShopBot.


Ron Brown

Diplomacy is the art of saying 'Nice doggie' until you can find a rock. - Will Rogers

[donframbach]

Thanks Ron, I was wondering if anyone has hooked up the 10-15 feet of 2.5" ShopBot supplied tubing to the ShopBot Dust Collector connected to a low vacuum "pressure" high volume dust collector such as the Oneida. You're right, the Fein does have a separate air circuit for cooling which prevents the motor from overheating if the main vacuum line gets clogged with debris.

[rgbrown@itexas.net]

Don,

One of the real problems is loosing chip velocity in the hose/pipe while in operation. The chips will settle out and a clog develops. A system can be designed to shut down the router on that occurance but, a keen ear will do the same.

There are so many varaibles, each system is unique. Brute force and overkill will usually cure ignorance and bad design.

Good Luck,
Ron

[gerald_d]

Donald you have an interesting and valid question . . . . . .

ShopBot says this on the website: "For dust collection on flat sheet goods. Shop Vac/Dust collector not included. Assembly required. With 10' hose and hardware" and this implies that you can use either a shopvac or a dust collector. There is a huge difference between the two styles of machines:

ShopVac: High-speed brush motor, whiny noise, small hoses (around 2" or less), small collection canister, fan sucks through filter, small filter area.

Dust Collector: Low-speed TEFC motor, roaring noise, big hoses (4" or more), bigger collection canister or bag, fan blows through filter, big filter area.

My gut feel tells me that 10' of 2.5" hose is too much of a restriction for a "dust collector" and that a big "shopvac" will give a better performance - until the small filter and canister get blocked. We use a homemade "shopvac" at the moment (big filter and canister, but still the whiny motor) and are wondering, like Donald, if the "dust collectors" will do a better job?

PS Anybody using a Woodstock? (http://www.toolpeddler.com/dust_collection_separators.htm)

[papadaveinwy]

Hey guys allow me to tell you what I did. 1. a three horse two bag dust collector 6" metal main line trunk y's to 4" to each machine ie. table saw, planer molder sander gang ripper machine, shopbot, each one with a blast gate to shut off or open as needed flex hose of 4" type to the bot with a copper wire inside and grouned to the bot and the main metal trunk (to insure no fires) this system will keep the bot clean of everything except a small amount of fine dust. I never have any problems except after running a large amount of MDF then I have to shake the filters clean as the fine dust from the MDF will clog the pours of the filter bags and thus slow down the flow. keeps the shop pretty clean, as you know I am shuting down the shop for now and just finished cleaning the main woodworking area after 14 months of work I only had one garbage can of sawdust that I swept up from the floor. not bad for as much as I do. David in Wyoming

[gerald_d]

Dave, your 4" line to the SB: Did you try to keep it at 4" all the way to the dust skirt?

(If I were to use a dust collector, I'd ditch the 10' of 2.5" and replace all with 4")

[rjguinn@optonline.net]

Gerald,I've used the Leigh Valley Tools (Canada-Veritas)version which is available in black or clear (PET) on a 44 gallon Rubbermaid container.2 1/2" hose from shopbot to lid & 4" to a 2hp Delta dust collector.Braided copper bare wire inside & out of all flex hoses.I'm very happy with the results. This lid was designed to work efficiently with a shop vac,but personally I would only consider the larger Fein unit because of hose size,power,quietness & dual fan design.

[papadaveinwy]

Gerald, Yes I kept it 4" all the way to the dust skirt this system will suck your pants off and give you back the change from all the money you make with the bot [
] David in Wyoming

[papadaveinwy]

Gerald, I keep 6" all the way on the main trunk with 6"x 4" y's to each tool then 4" to each tool, and try to keep the runs as straight as possible because each turn in direction will change the static pressure, and therefore change the suction power this will give you a book on the subject (http://www.rockler.com/ecom7/showdetl.cfm?offerings_id=10396&objectgroup_id=32& catid=7&DID=6). David in Wyoming

[cncrouting@attbi.com]

Hi. Just been running my machine for a bit, but have used a cheap dust collector I got on ebay with extremely good results. My unit cost under $200 with shipping (think I got it from RAF supply). I have a prt 120, so if anything, the distance problem is exacerbated for me. Also have the fein turbo III. It does indeed have a separate air draw for the motor cooling, so you can run for extended periods. More of a problem than it's capacity (14.5 gallons, i think), has been that the filter clogs very quickly on the fine dust generated by a mortising bit in mdf. While a drop out would be great for increasing volume, I find that the filter reduces effectivity well before I reach tank capacity. The dust collector effectively solves this by passing all the crud through the motor, at least the fan blades. It filters stuff later, in the bags. Again, my cheap collector from ebay has done very well. If you got a good one, I'd imagine it worked even better, and quieter.

Best of Luck.

Neil

[valensign]

Ok Im not a Phiysics Major here so all I did was buy a Harbor freight single bag 3hp Dust collector $180 Attached a 20 feet of 4 inch Dryer Hose. Looped it up and over the Light Fixture.(That works Nice cause all the static Electricity gets grounded out by the light.. Also Saves power
Then used a 4" to 2" Reducer to attach an old Shop Vac line that attached to the router.. I made a Nylon plate that attaches to the top of the Z and it tightens and loosens as need to adjust the Hight with my Homemade dust skirt.. I machine around 6 to 10 hours a day and never had a problem yet with clogs or dust build up. I can stand in the same room with the router and talk on the phone Unless the router is cranked up all the way... It ain't pretty but works great.. I even put a Tee in so I can attach a 1 1/4 hose and attache it to my sanders and sanding table..