Dust collection system vs. Shop Vac

[DaveStL]

I am plumbed with 6" pvc, and go down to 4" flex as close to the machine as possible....

I read thru Bill's site and agree with the information on using larger pipe sizes....

What he said! I originally bought the HF "2HP", but it was missing a bunch of fasteners and I took it back and got the Delta 50-760 and a Wynn poly canister. I'm still fooling with setup, need more time in the shop. Some sawdust accumulates in the bottom of the Jet saw. It's a velocity issue--I really miss the shrouded blade on the BT3000. The big-mouth Shark sucks sufficiently on the top, though.

While it didn't cavitate (at least not noticably) there was a definite strain on the DC's motor.

For a 2.5" or smaller port you could open another gate w/o anything on it part-way to keep velocity up in the main. I wouldn't worry about starving the blower on a DC; power draw goes down w/ less airflow, and the motor should have its own fan. You might have been hearing high velocity through a small opening elsewhere in the system?

I agree, for a hand tool the shop vac hose is a lot easier to handle. At some point I'll make a stand for a DC hose/nozzle to pull air from next to a sander. BTW, I tried running two gates at opposite ends of the shop wide open as an air cleaner, and it seemed to help.

Dave

[LCHIEN]

Phil and Larry, the DC numbers for a good one like 1.5 to 2 HP are claimed to be 1100-1200 CFM, usually after hoses and everything they may do 800 CFM. The HF is claimed to be 1600 CFM (Who are they kidding) but the HP is more like 1.5 and the impellor smaller than the name brand's 1.5 HP. The resulting airflow on the HF DC in comparitive tests in magazine articles has generally clocked around 550-600 CFM.

Shop vacs OTOH are rated around 50-100 CFM, but I've never seen actual numbers, so theose are probably under ideal conditions just like DCs, never as good as claimed.

10x to 15X then is probably a good ratio for DC to SV air flow numbers I think.

[cgallery]

Loring, I was using my Ridgid's specs of 160-CFM (which my poor-man's measurements seem to conform) and comparing to the maximum of 400-CFM I've been able to get through a 4" pipe/hose (which BP seems to confirm).

Using a 5" or 6" pipe on a larger DC would absolutely change the balance of the equation, as you show.

[leehljp]

If you're hooking a 4" DC hose up to a 2.5" tool port, you can expect that advantage to all but disappear.

I kinda disagree with this - from practical experience. I hooked a strong large Sears shop vac to my Delta planer and the planer put out more sawdust chips than the vac could pull effectively. Some of the chips made their way back down to the roller behind the cutter heads and were squished into the planed board, making chips.

Where I disagree with the statement is in that a shop vac is made and geared to 2 inches or 2 1/2 inches all the way. One constriction point of 2 1/2 inches will cut the suction down as you noted, but the closer it is to the action end, the more power it will have. The placement of the 4 to 2 1/2 constriction point greatly affects the efficiency of the vacuum/suction.

NOW to the advantages of a DC over a Shop Vac in a practical manner: My first paragraph relates to this. A planner puts out a huge amount of chips over a 10 to 12 to 14 in wide space. Even a large 2 1/2 inch Shop Vac will RARELY pull enough air (suction) to cover the area and chip volume produced by a 12 to 14 inch thickness planner. A decent 4 inch DC WILL be able to do that.

Saying this in different terms: A thickness planer planing 1/16 to 3/32 in (or 1/8 in if you are brave) off of a 12 in board will show up the difference in a good DC versus a shop vac. There won't be any question about the differences. DAMHIKT.

[rberrybabylon]

Pretty much totally agree.

My experiences pretty much confirm the advice already given.
I made the mistake of buying a single bag DC, on special discount, from Craftsman and found it couldn't handle my planer. On the other hand, my Craftsman ShopVac not only handles my planer but, with the ShopVac Dust Collection System (a set of 2.5 in. rigid pipes, blast gates, and Y's) it allows me to attach to most all of my equipment and does what I consider a pretty darn good job of keeping my garage wood dust free. I put a 3 micron filter in the ShopVac.
While I'd love to have a big fancy DC system, as a part time WW, it just doesn't make sense. It costs too much for me.
So, I'd say, if you have the money, the DC is the way to go, but, if you're like me, the ShopVac system fills the bill just fine.

[Navycraig]

A Lot Of Great Information

Thanks to all of you for taking the time and effort to post your thoughts on this topic. It gives me a ton of great information to consider that I have not even thought of yet. Heck, I figured I'd buy one, hook it up and be done with it, but now I see that I need to consider much more when making my choice. I'm sure I'll end up with one eventually as my health is important to me.
KSUM...I'm down in St. Mary's County...Callaway, MD...in the area of Naval Air Station Patuxent River. I may just take you up on your offer to stop in for a visit.
Thanks again...to all.
Craig

[cgallery]

Well, I think the post by Hank and the subsequent post by rberrybabylon pretty much sum it up: When it comes to dust collection, we each have to find what works for our own shops.

[dkerfoot]

I hooked a strong large Sears shop vac to my Delta planer and the planer put out more sawdust chips than the vac could pull effectively. Some of the chips made their way back down to the roller behind the cutter heads and were squished into the planed board, making chips.

The issue here I think is just trying to move that much bulk down a 2" or 2 1/2" hose.

As I understand it, having any restriction (a 2 1/2" connector) on a 4" hose will lower the CFM of the whole works, but having that small of a hose the whole way will tend to clog easier than a 4" hose, despite the same basic airflow.

I'd be interested in seeing what the actual CFM of my HF DC is when connected to 10' of 4" hose coupled down to a 2 1/2" port at the end. I am not convinced it is higher than 100 to maybe 200 CFM

There is no doubt that my DC works better in collecting chips off my planer. There is also no doubt that it is more convenient when it comes to emptying. I also get some advantage having a Wynn filter cartridge.
I rigged my router table to have a 4" port on the cabinet and a 2 1/2" port at the fence. It definitely does a better job than when I was using just the shopvac on the fence port.

BUT - I am not convinced that I get a reduction of fine dust while using my tablesaw (CM 21829) with the 2 1/2" port - even with the sharkguard.

[djcannon]

Shop Vac's Cyclone

I have been using a shop vac for a few years.
Had some problems with sawdust clogging the thing when using my drum sander to the point where I had very little air flow. I made a little cyclone (8" diameter) from the plans on Bill Pents site it has worked great. I can easily will fill a 5 gallon bucket with dust from my drum sander without a notable reduction in suction. Sometimes when I want more suction I remove the filter and hook up a hose to the exhaust end of the vac and blow the dust that escapes the cyclone out the window. I live over 100 yards from any other houses and can't even detect sawdust comming our the exhaust end. I like many others wish for a larger setup but am feeling content with what I have.