SDD inlet 5" to 6"??

[Ryan Haugle]

Hi guys,
Thinking about using a 5-6" expander for my SDD so I can pipe a full 6" pvc system in my new shop. Would this work? The inlet on the sdd is only 5 so it would get choked down right as the dust enters the sdd.

Running a HF 2HP DC motor

[Ben Rivel]

Well, it wouldnt give you any advantages as far as dust collection goes. In fact it would probably make the system work less efficiently seeing as how youll be choking it down right at the inlet. Id suggest selling the SDD and going with the SDD XL (LINK) if you want a 6" main.

[Ryan Haugle]

So would 5" galvanised duct pipes be better? Or choke it down right away to 4", and use PVC?

[Ben Rivel]

So would 5" galvanised duct pipes be better? Or choke it down right away to 4", and use PVC?

That HVAC ducting is usually too thin and can collapse you. Its been for air being blow out of it, not suction. Oneida makes a 5" to 4" reducer and that would be the normal approach. When they designed out a build for my shop, they took the 7" inlet of the V-3000 and immediately reduced it to 6" for a 6" main.

[Jim Dwight]

I am thinking about what size and what material for my HF/Oneida setup right now. Gray house studios used 6 inch on their setup but also used the Rikon impeller. I think 6 inch would work on the smaller of the two Oneida super dust deputies. There would be restriction at the inlet but less loss along the run of pipe. The only issue would be if the velocity of the air is too low to keep the dust moving and the pipe plugs. If that happened the Rikon impeller would probably fix it.

The DC airflow is strongly a function of the restriction of the entire system of piping it is hooked up to. Bigger pipe (and non-flex pipe) means less restriction. I saw a youtube today where they claimed flex has 3 times the resistance of an equivalent length of straight pipe.

I've also seen multiple reports of satisfactory results with the HF and 4 inch pvc waste piping. The velocity would certainly be high enough and the price is low. The question is the airflow. I'm sure it would work but the airflow would be significantly lower than a 5 or six inch system. I've also seen reports that metal flows better than plastic.

I am skeptical about Oneida's claims that HVAC piping will collapse. I am confident it will not happen with a 5 or 6 inch system metal system that has a gate open. If you put in a 4 inch and turn on the DC with all the gates closed, maybe. I am thinking of putting micro switches on each gate and using a relay to turn the DC on when the gate opens. That should greatly reduce risk of collapse. But maybe Oneida is not just marketing their more expensive thicker pipe.

[Ryan Haugle]

I would hate to have to go to 4", hoping someone has done the 5-6 reducer and has good news. A new DC system is in the future, but years away still.

[Andrew More]

I am skeptical about Oneida's claims that HVAC piping will collapse.

* Same, with the caveat it depends on the system. I've got a 1 1/2 HP cyclone capable of creating 10.5" of SP and I haven't had any issues with 26 gauge ducting. I'm sure it's possible to create enough suction to collapse HVAC ducting, but I don't think it's likely to be found on most dust collectors. Maybe some of the 5 HP systems, but even then I'm skeptical.

[Jim Becker]

So would 5" galvanised duct pipes be better? Or choke it down right away to 4", and use PVC?

Use 5" 26 gage "stove pipe" which looks identical to the typical 30 gage HVAC pipe, but can handle the pressure/lack-of-pressure inside of it without collapsing. It's available at most of the 'borg (look for the 26 gage notation...silver labels at HD) or an HVAC supply.

[Jim Andrew]

My local Ace hardware handles 26 gauge galvanized. Might check with your local Ace Hardware. They are cheaper than the competition as well. They do NOT handle the Y's, theirs is more like a T, but you can order the Y's and buy the rest at ace.

[Jim Dwight]

I appreciate the comments, they help me and I hope they help the OP. I am still a bit uncertain what I will do. 6 inch PVC comes in longer lengths and is a little cheaper but 5 inch metal avoids the need for a separate wire to dissipate static (so dust will not collect, not because I think it will ignite or blow up) and it seems more consistent with the airflow of the HF DC I already bought. But with the Rikon impeller, it probably handles 6 inch fine and it might without the impeller change. Biggest down point to the 5 inch is the availability of all the fittings. But the comments on 26 gauge available a couple places locally helps. I've looked a bit on the internet and I think the pieces are available. It may be necessary to go with Oneida for some pieces but their prices are not low.

I worry most about airflow for my CMS/RAS. I am thinking of putting a hood over both machines and I will need a bunch of air to make that work. Might have to make it two hoods regardless. I don't think the table saw will know the difference although if I add overarm dust collection it might. My jointer can put out a bunch, it used to clog with my old 1hp DC. I don't have a connection at the thickness planner yet but it can also put out the chips.

[Bill Jobe]

I honestly think that if you take a close look at your 2hp intake, it isn't even a full 5" inlet. You still need to factor in the grill that air passes through. It displaces some of the opening.
That having been said, I love Ferncos!

[Jim Dwight]

The only part of the HF DC I plan to use is the motor with the blower attached. I will look again before installing it but I did not notice a grill. With the cyclone I do not need one and will remove it if it is there. Without a cyclone, a grill can be useful to keep big chucks from dinging up the blower. But the cyclone will prevent even pretty small things from getting to the blower. My prior experience is the grills like to plug with plane shavings. That was a waste of time.

[Steve Eure]

Ryan, I just went through this samw thing with my HF DC. I ended up using a fernco fitting and it worked very well to attach the SDD to the blower housing.
https://www.supplyhouse.com/Fernco-1...st-Iron-or-PVC
This is the best place that I have found to buy these types of fittings.