Dust Collection Advice Sought

[michael dilday]

Get a copy of the CFM Performance curve for your DC if you can find it. You can use Bill Pentz spreadsheet or your own calculations and calculate the CFM at the longest run on each branch. Make sure you have sufficient air velocity in the verticals and horizontals to move the dust and chips. Bill Pentz website has this info. The largest pipe you can calculate and maintain the velocity needed is your best bet. My first installation in my double garage with short runs was 4" PVC and it worked great. My new shop has a longest run of about 50 feet and I used 6" spiral mains and 4" spiral drops. The big box HVAC duct has the wrong connection direction so the chips can collect at each connection and eventually block the pipe. Better with PVC or true dust collection pipe. I bought mine from Rockler. Probably paid a little more but it was very easy to purchase what I needed there. One time expense. For the drops it is important that you connect to the main with a WYE horizontal then 90 down with the drop. If you exit directly down then chips and dust will drop into the vertical pipe and build up at the gate. If you get too much build on less used machines it is possible that the DC will not be able to move it.

[Mark Daily]

Bob, why are you redoing your current system? I considered changing my 4” system to 6” but decided not to because it works just fine as is.

My Dylos particle meter tells me the current system is doing a good job at collecting dust at the source and what it misses is quickly filtered out by the hanging filter which I have running all the time while making sawdust.

Besides, 6” parts are much more expensive.

[BOB OLINGER]

Hi Mark,

I only considered changing to 6" to get better performance as I recollect seeing a lot of posts promoting 6" over the years. But, given a variety of responses and my system has worked OK, I think I'm going to stay put.

Thanks.

[Andrew More]

I only considered changing to 6" to get better performance as I recollect seeing a lot of posts promoting 6" over the years. But, given a variety of responses and my system has worked OK, I think I'm going to stay put.

FWIW, I've consistently seem very high levels of improvement by increasing the intakes. In some cases I've gone from 2 1/2" to 4", or 4" to 6". It really does make a difference. That having been said, the purpose of the system is not to create the most air flow, but rather to collect dust. If your situation is similar to Mark's then, stick to 4". If you've still got issues, increasing some, or all of the ducting makes sense.

[james manutes]

Before I swapped my ducting , I would look at the impeller you currently have . If it's 10 to 11 inches w/straight fins or blades , you could upgrade for about $110 or so . Most all 1.5 HP to 3HP housings are the same size . Most are 3/4 " or 7/8 " shafts . IF the rotation is the same direction , you could try it . Grizzly has a 1.5 HP collector w/ 12 3/4 " - 85mm high impeller for a 3/4" shaft that is likely to perform better . Also 12 3/4 " -95mm (taller) w/ 7/8" shaft is from their 2 and 3 HP models . Open the inlet on the housing to 6" , upgrade the impeller are things I'd check first. I'm not sure what that Delta DC comes with , so I'm just suggesting . Good luck in whatever you do .

[james manutes]

Well I just looked at the Delta 50-760 , and I don't think those Grizzly impellers I suggested will work . Wrong rotation I think . An upgrade is possible , just need the correct impeller . Again , good luck .