Replies

1. 
   daveinnh | Jul 16, 2007 01:50am | #1

   I haven't heard of craftex, but I'd go with 6" main duct and add a reducer entering the cyclone.  Larger duct dia. provides less flow resistance.

    

2. 
   AntzyClancy | Jul 16, 2007 07:20pm | #2

   Change the intake to 6 in, use a 6 in main, and run 6 in drops to all of your machines.  I wouldn't recommend anything else.

   Todd

3. 
   BruceT999 | Jul 17, 2007 06:24am | #3

   Ivan, your DC is probably rated at 1500 CFM through its 5" inlet opening to the impeller housing with no restrictions on the outlet side. Generally there is no advantage to piping at a larger diameter than the blower inlet.

   Judging by the fan curves of major cyclone manufacturers, when you add your garbage can cyclone, your CFM will drop to something like 1300. According to DC books, like "Woodshop Dust Control", 30' of 5" smooth pipe will cut CFM by another 100 or so. Every 90* bend will cost you 70-100 CFM and reducing from 5" to 4" will cost about 250 CFM. Finally, you lose as much as 250 CFM (depending on the fan curve for your machine) at the dust hood of the tool. With all those losses added up, your system could easily run at less than 500 CFM.

   Running 6" main duct will reduce friction losses, but it is likely that the velocity of air would be too low (below 3500 FPM) to keep sawdust suspended in the air, resulting in debris piling up in the ducts, especially at elbows. It takes a minimum of 700 CFM for 6" main line to run at 3500 FPM, but it takes only 476 CFM for 5" pipe.

   I'd recommend that you get the book mentioned above (available on the Taunton site), get fan curve data from the DC manufacturer and design your ducting system according to the author's recommendations. Then do the calculations to find the largest pipe size that will keep main line velocity at 3500 FPM or above and branch velocity at 4000 FPM or above.

   BruceT
1. 
   ivanbl | Jul 17, 2007 06:26pm | #5

   Your advice on inlets and ducting makes sense. Some have suggested increasing the inlet size, but I figure the motor has been engineered for that 5" opening, for that reason I will leave that alone. (to be on the safe side). I will take a look at "Wood Shop Dust Control. I will also have a look at Bill Pentz's dust collection web site.

4. 
   mudman | Jul 17, 2007 08:20am | #4

   Bruce is right adding the trash can will cause a signifigant loss of suction or CFMs or whatever. Is the flange on the inlet removable? A 5" inlet is strange on a 2 HP DC.

   Pardon my spelling,

   Mike

   Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.

1. 
   ivanbl | Jul 17, 2007 06:35pm | #6

   Yes I triple checked. The HP is 2 and the inlet is 5". I can see how I would lose suction with a trash can separator. Im thinking of making a trash can separator with 5" inlet and outlet. I hate to say it but this is a trial and error project. If I run suction to only one machine when running and close all other blast gates. Im hoping to get enough suction.
   thanks Ivan

1. 
   mudman | Jul 17, 2007 07:30pm | #7

   If the DC runs like a 2 hp unit should you wont have any issues.Pardon my spelling,

   Mike

   Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.

2. 
   BruceT999 | Jul 17, 2007 07:36pm | #8

   "Yes I triple checked. The HP is 2 and the inlet is 5"."I'll rain on your parade a little bit here. Your motor horsepower is rated at 2, but at 9A it is really only 1.725. [W/746 = HP Amps x volts x single-phase power factor = W] 9A x 220V x 0.65 / 746 = 1.725 HPMost motors are over-rated. My Delta hybrid saw is rated at 1.75hp, but at 15A, calculates to 1.57hp
   BruceT

1. 
   ivanbl | Jul 17, 2007 11:10pm | #9

   There should be a law against that sort of stuff. You would think 2 Hp really means 2 Hp. All in all though I won't complain. This new dust collector is bigger than my old one. Also I bought this model as an instore special. I paid $385 Cdn. I figured I could'nt go wrong.
   Ivan

1. 
   mudman | Jul 18, 2007 05:23pm | #10

   Dont feel bad, the theoretical watts to hp formula is just that, a theoretical equasion. There are several measurements of Hp including brake hp, peak hp, continous hp, and others I have never heard of. The Amp draw is a good clue though. Some of the crappy cheepo Chineese stuff will have a large discrepancy.Pardon my spelling,

   Mike

   Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.

2. 
   ivanbl | Jul 19, 2007 03:38am | #11

   Thanks. Out of curiosity I will compare other models and see how they compare to mine. Tomorrow I will start buying some of the duct work and see how this project goes.
   Ivan

5. 
   CarvinChris | Jul 19, 2007 05:17am | #12

   I have a Bridgewood 2hp DC with a canister filter rated at 1100cfm that has a 5" inlet.  Attached to it is a 4" hose that goes to a garbage can cyclone, out of the can is 4" hose to 90 degree fitting and then a 'Y' fitting where one leg goes to my table top dust scoop for my power carver and the other leg I use to attach to my different machines to collect dust and chips.  I have a blast gate before the two 90's to my dust scoop and another right off the 'Y' to the machine hose.

   Other than having to hook and unhook the machine hose which is 10 to 15 feet, depending on machine location, the whole system works quite well without any noticeable drop in airflow--although I'm sure it does drop some.  The dust and chips are in the bag and can and not all over the place.

   One small tip; if you have a bag for collection on your DC, wrap a strip of foam weather sealant (the sticky back stuff ya use around doors and windows) around where the bag and holding band go on the DC. This makes the bag easier to install and eliminates any blow-by out of the bag.

   Have fun,

   Chris

1. 
   ivanbl | Jul 19, 2007 05:48am | #13

   Thanks for the tip. A strip of foam seems like an excellent idea, I know there have been a few times when my patience has been severely tested when putting on that lower DC bag, as well as dust escaping.
   Ivan