Brandon,
i would like to offer my thoughts, I am building my D.C. System as I write this. I have budget constraints and I wanted to make the work area safe from fine dust and get rid of the saw dust off the floor forever. Several years ago I built a cyclone from 10 inch HVAC pipe it worked great with my shop vac for removing the saw dust out of the cabinet of my Ridged 4512 TS. However it did not have enough air movement to extract the dust from the spinning saw blade, the top was covered in saw dust.I wanted to solve this problem. I was gifted a Harbor Frieght advertised 2 hp. Unit (more like 1.25)
i bought the Supper Dust Deputy for the Cyclone. After using my home brew Cyclone I will never use any D.C. With out a Cyclone. The HF D.C. Is a little under powered but works with a single hose connection to tools with a good smooth flex hose. And that was with using the bag filter I mean the dust spewer. Bad idea for collecting fine dust. So I bough the Wynn 35A nano filter to solve this problem. With the major components on hand I statered war gaming how I was going to set this up. I watched every YoUTube video on D.C. With Cyclone separators. I knew I needed short runs of ducting and short as possible for any flex hose.the shorter the better. The fan or impeller in the HF is 9 3/4 inch diameter, not very big but it moves air. I also knew I would get better performance if any curves where removed from ducting and hoses namely the the hose that runs from the impeller exhaust side to the filter. To make this work I built a frame to mount the motor/ fan/ blower on in a vertical shaft fashion, this accomplished two things. The duct from the suction side went strait to the top of the Cyclone. I also removed the factory 5 inch connection as it restricted airflow. I made a new cover with a 6 inch HVAC takeoff that fits perfectly into the SDD. The exhaust from the blower now goes straght into the HF filter frame with the plastic bag at the bottom. The Wynn filter where the dust spewer use to reside.
making these changes made a big impact for performance, sorry I do not have any numbers to offer.
as for the impeller size bigger maybe a good or bad thing. I see where guys have changed out the impeller for the Rikon 12 inch impeller, I am at 1900 feet Mean Sea Level if I were at Sea Level the air density (lower altitude the more dense Air) maybe be more than what the motor can handle drawing more current than what the motor is rated for. ( high Alt such as Denver a bigger impeller may be beneficial to move more air ) with D.C. It is all about low drag and a high volume of air flow not suction like a shop vac.
Next Duct work: this can get complicated to keep it simple long sweeping turns should be used, avoid sharp 90's they are velocity killers rember we want high volume high velocity air flow. To keep the fine dust in suspension and to move chips.
when making branches avoid Tee's for the same reason use Wyes'
if you have to make turns I would suggest using 2 45 degree with a short section of pipe between the 45's this will help reduce paristic drag, drag is bad.
The size of the pipe: again this can be complicated, as an example I have seen many folks with the SDD use HVAC reducers to connect the plenum pipe to the SDD the SDD has a 5 inch input. I recommend staying with 5 inch pipe.
why? If you go down to the common 4 inch PVC thin wall Drain pipe you will lose a great deal of air flow,
if you go up to a 6 inch pipe the velocity will slow down and the fine dust will settle. Think of it this way you have a vertical 4 inch pipe 18 inches tall and a garden hose with 60 psi filling the pipe from the bottom the objective is to flush out the golf balls sitting on the bottom the pipe. You open the valve and water floods the pipe a few balls are forced off the bottom of the pipe but not out of the pipe. The water flow rate is not enough to over come the weight of the balls. The ball Starts to sink this creates turbulence in the water the other balls just get churned up and down. But not out the top of the pipe.
Now take a 2 inch pipe with the same water flow rate and the balls will be propelled out of the top of the 18 inch tall pipe.
In this case it is the flow rate that is in a smaller pipe that over comes the weight of the balls. Not the pressure.
some may argue this point but just go with it. The water stream is not directed at the ball in this situation.
That is not to suggest using a smaller pipe than in the inlet to the Cyclone should be used. Use the same size of pipe all they way to the tool and reduce only if nessesary, if your Table saw has a 4 inch port make it a 5 inch port. If it is a hand sander you are going to have to sacrifice performance and reduce to size of the pipe to connect to the sander. Oh but this will reduce the airflow to suspend the dust right? At another blast gate farther away from your sander upstream crack the blast gate so that you get more airflow to move the dust. Theoretically you would want to open the blast gate just enough to make up the difference in air flow that the small sander duct choked off. Listen to the impeller speed to determine how far to open the blast gate. As the impeller gets more air the speed of the impeller will slow down. Do not bog down with too much air, as in gate that is fully open. The velocity will drop off.
Now presents another problem 5 inch pipe! Where do you find it short of Onidea or some other high priced supplier. After all most of us are hobbyists we need to be realist about what we spend. 5 inch pipe! Well drillers in West Texas use 5 inch pipe for wells however I have not found any fittings wyes or any thing other than couplers oh this is a126 psi pipe not schedule 40 or DWV or Schedule 20.
What I did was go to a local shop that makes HVAC duct work. He made me 5 inch wyes that fit on the 5 inch pvc and used foil tape a good quality tape not duct tape. For the turns I went to an HVAC supplier for those. And tape all the seams even on the ribs where the bend is made. I tested for leaks using a smudge stick.
if I did it over again I would use a good true 2 HP blower such as Grizzly setup with a the Cyclone. A turn key setup it uses 6 inch duct work has a bigger fan a better fan curve (more air flow) for a little bit more than what I have in my cobbled setup. But it works.
From a man with few words,
i just use a SE a lot of the same words over and over again.
Read ad what Bill Pentz has to say. Like others you have make up your own mind but research research!
Lane
Reply With Quote
Originally Posted by Brandon Hanley
