DC system performance using Manometer

[Larry Richardson]

So my "efficiency" workshop is complete :) This is in 3/4 of a 1 car garage, but meets my needs right now. I have built a Bill Pentz cyclone, with an airfoil I got from a member here, and coupled it with a Leeson 5hp motor and 2 wynn filters. 6" PVC and 6" to the tools whereever possible.

These are short runs, and I think the longest is about 15' from the tool to the cyclone, including the flex. There are only 2 drops and a single straight run. All joints sealed with duct sealant and gorilla tape.

My key item is the router table. I have put this on an enclosed cabinet, and sealed and minimized the DC area as much as possible. I have also done some smoke tests to verify no noticible leaks.

I'm not sure that I am getting proper performance from this, and figured that I need to do some measurements. While I have vacuum, I'd say it is less than the shop vac (yes, I know volume vs velocity).

Just looking for some sanity checks, as I think this thing should be seriously overenginnered for my application and should be able to easily control the fine particle from routing MDF..

I have a local source for a Dwyer Slack Manometer, and was considering starting here as a quick check of performance and troubleshooting. I know others use a gauge & pitot (~$100 from ebay) but I was thinking of starting a little cheaper.

Will this get me there for some general ballpark measurements ?

[Rod Sheridan]

Larry, at risk of insulting you, have you allowed enough openings in your router cabinet to let make up air into it?

To control fine dust you need lots of air flow which means large openings to let the air into the cabinet.

Also are you drawing air from both the cabinet and the hood over the router bit?

Regards, Rod.

[Ed Labadie]

Before I went through all the trouble of using a meter....I would unseal the cabinet and let some make-up air in, sounds like your using the DC as a vacuum pump.

I did see a pic the other day of a router table with an adjustable vent on it, the circular type thats used on oil furnaces, thought it was a pretty cool setup.

Ed

Found it http://www.rockler.com/product.cfm?page=22208&filter=router%20table
You should be able to get one from a hvac place.

[Ken Garlock]

Hello Larry. It sounds like you have done a through job configuring your DC.:cool:

I built the Pentz cyclone from a kit and procured the impeller and motor from Bill's recommended sources. I too use the Wynn filters.

My recommendation is: a DC is not a NASA application, so don't over think the project. I have 6" PVC all around my shop connecting to 6 different tools. I some times forget to close a blast gate and with 2 6" gates open the cyclone still does it job. The 14" impeller coupled to the 5hp Lesson will, as Willie Nelson once said, suck the chrome off a trailer hitch. ;)

So, go build something and then look at the dust situation. Most, if not all, stationary tools will not provide the internal architecture to permit the extraction of all the dust. You will from time to time need to open up the saw cabinet and shovel out a cup of two of dust. I just push it down the dust collector hose connection.

[John Coloccia]

If you're going to spend money on measuring equipment, skip the manometer and buy a Dylos.

You will definately get less suction from a DC than from a shopvac, and it will get worse as you reduce the size of the inlet. For example, my shopvac does MUCH better with the 2 1/2" tools than my Clearvue. The Clearvue can no way generate enough pressure to suck any volume of air through a 2 1/2" inlet (and pretty much, neither can any other DC system you might consider using in your garage). 4", even, is pretty marginal especially if you have more than just an inch or 2 of 4" coupling. I have the Clearvue Ridgid conversion now for the small tools. Pressure isn't what determines good dust collection though. It's moving lots of air at high speed, which the Clearvue most certainly CAN do (and yours too!).

[Larry Richardson]

RE: Router table. Good question on the amount of air going in.. I did put a 2 1/2" port from box (next to 6" ) to the router fence DC port. perhaps I need more and can try that. I've essentially made the same as the rockler without the inlet vane.

My biggest concern (next to health) is the MDF raised panel doors I'll be making this week. Last batch had that wonderful fine particle dust everywhere. As in "all over SWMBOs stuff" everywhere :o, so the DC was a mandatory requirement. I do use a respirator when working with that stuff too.

Thanks Ken, as long as it gets the little stuff, and can help keep SWMBO happy, I'll be fine.

[Peter Aeschliman]

RE: Router table. Good question on the amount of air going in.. I did put a 2 1/2" port from box (next to 6" ) to the router fence DC port. perhaps I need more and can try that. I've essentially made the same as the rockler without the inlet vane.


There's your problem, man!

[Larry Richardson]

There's your problem, man!
do you mean adding the port, or not having enough ingress of air ?

[Bill Arnold]

I built in a slot on my router table dust containment box equal to slightly less than the area of the 4" port. The only other openings are those in the router lift mounting plate. I have a separate 2.5" port for my router fence. This system works great in collecting most of the dust and chips. If you don't have a source of air going into the router cabinet, you'll get no dust collection at all.

[Larry Richardson]

Ok, I think I've got it - I'm likely starving the poor cyclone to death !

So here is a plan ( feel free to bash me about if it's wrong :) ).
I have an old 4" blast gate not in use, that I can attach to the router box.

Then I can use an ammeter and adjust the gate until I get a minimal reading on the DC.

I might just nix the 2 1/2" dust port and run that off the baby cyclone ( Thien lid and shop vac). Heck, with enough suction going on, I won't even need feather boards :D

[Bill Arnold]

... Then I can use an ammeter and adjust the gate until I get a minimal reading on the DC. ...
Minimal current draw by a DC means no airflow.

You can make all kinds of measurements on your system or just do like I did which is draw on the experience and knowledge of others. Reading through online information, posts in Forums and asking a few key questions is all I needed. That plus my own experience has given me an excellent dust collection system.

[Rod Sheridan]

Ok, I think I've got it - I'm likely starving the poor cyclone to death !

So here is a plan ( feel free to bash me about if it's wrong :) ).
I have an old 4" blast gate not in use, that I can attach to the router box.

Then I can use an ammeter and adjust the gate until I get a minimal reading on the DC.

I might just nix the 2 1/2" dust port and run that off the baby cyclone ( Thien lid and shop vac). Heck, with enough suction going on, I won't even need feather boards :D

Larry, you're on the right track, except for the vacuum idea. You need air flow, not vacuum, use your dust collector.

Run a 4" hose to the cabinet, make sure you have at least 20 square inches of opening in the cabinet for airflow (i.e. a 4" X 5" hole, or 2" X 10")

Run another 4" hose to the router fence hood, and make sure that there's room for the make up air to get into the hood. If you seal off the hood with the work piece for example, there's going to be no air flow, and then no dust colection.

Dust collection is all about volume, which is why a vacuum doesn't work, except with hand help power tools designed for that application.

Regards, Rod.

P.S.

Go to the Felder USA website, and register so you can see the videos. Watch the video where they make a desk, there is some shaper work in that video.

Pay attention to how much open area there is on the shaper fence and hood, especially when they are shaping the curved pieces. All that space is required to get high volumes of air flowing to pick up the chips and dust, choke it off and you don't collect anything.