Opinions on a planned DC setup.

[John T Allen]

First post, but hoping to to find an active community around here to share and learn from. I'm in the progress of setting up a proper dust collection system for the 2-car garage that is my shared workspace, and looking for some feedback on the planned ducting plan. The system will be a 2-stage with cyclone, built around a G1030 3HP attached to a Super Dust Deputy XL with a 55 gallon collector. Venting will be outside as I have potential allergy issues (Michigan, but the garage is not heated in any case), but live on a decent sized bit of land, so no worries on doing so. I've sketched up a provisional space plan below (forgive me for the non to scale elements, but hopefully this is sufficient.

As I want a relatively easy setup and have the potential for changing it up (plus managed to get some secondhand), I'm planning on using a clamp together system (combination of Nordfab and Blastgateco).

From the SDD inlet I intend to run a length of Nordfab rigid steel flex to gradually transition into the line and get a little height to get it up out of the way (its a 10ft ceiling, with open trusses for hanging). From there I’ve been playing with a few different configurations - initially it will be for 3 drops, but I intend to expand to a fourth when if I decide to upgrade the tablesaw - the drops are as follows:
1. Drop 1 to bandsaw, which requires two 4” inputs (Grizzly 17” 503X2)
2. Drop 2 to jointer, which requires a single output (its a G0500 Jointer, so I’ve got a 4” port currently but may expand to 6" eventually).
3. Drop 3 to Planer (DW735) and dust shroud for Lathe

Plan is to minimize the length of flex to any tool with a drop (1-2 feet at most) and keeping the transition as close as possible. I’d like to run the duct at close to roof level or a foot or so below.

For the external venting portion, from the DC out I've got a custom transition to 6" and then I'm planning to go out the left wall above the window to the left of the box indicating the DC, through either flex or insulated hvac to drop the noise a little, and then out through the wall to some sort of vent in the vinyl siding (any suggestions?).

DCPlan.jpg

Few specific questions:
1. Does the ductwork plan seem reasonable for the length of run?
2. Does anyone have experience with the best way to connect Nordfab to a SDD XL inlet?
3. Is it better to have the Ys axis vertically aligned, or horizontally?
4. Am I making any mistakes with the transitions?

Appreciate any guidance and insight.

[Stan Coryell]

I'm sure others will add in. I didn't do any numbers, but I'll point a few things out.

I'd stay away from any flex in the main. It is loaded with friction and noise. Use two 45* elbows. If you can, leave 3 or 4 feet of straight pipe between the collector and the first elbow. This will help straighten the air.

I'm not sure what "long radius" means, 1.5x diameter is fine. Laterals or "Ys" need to be on the side or top, not the bottom. If the drop is 4", use a 4 inch lateral and blast gate. You need velocity to move dust. As long as the flex is less than 5' and reasonably straight, you shouldn't see any significant friction loss.

To keep the discharge noise down, size at least 2x larger. For the discharge: an elbow with a bird screen is fine.

[William Hodge]

If you have allergy problems, it would be a good idea to put the cyclone and dust barrel outside of your work space. Dumping the barrel out is a dusty job. If the barrel fills up, that disaster will be outside when you have to clean out the cyclone.

Keeping outside air outside is worth it even if you aren't heating. In the summer warm air will come in through the dust collection system and be delivered to machines. I put a blast gate on the main lines out of the building. The blast gate should be outdoors, because pressurized air will leak out when your collector is running.

If you're venting outdoors, you might not need a cyclone. I just shoot everything into a vented box on a trailer.

[John T Allen]

So even if its something like this would still be a poor choice? https://www.grainger.com/product/NOR...ct-Hose-45ZD89

If so I'll rethink that element. Yes, by long radius I meant 1.5x diameter.

Am I correct in assuming the reasoning for that issue with Ys is because if its align downwards there is loss of larger particulates down the spot as flow is traveling from a more distance run?

Wouldn't constricting the flow to only 4" on the drop reduce the potential? At least from the tables, isn't 4" going to limit the CFM rate you could pull out of the pipe?

[Stan Coryell]

So even if its something like this would still be a poor choice? https://www.grainger.com/product/NOR...ct-Hose-45ZD89

If so I'll rethink that element. Yes, by long radius I meant 1.5x diameter.

Am I correct in assuming the reasoning for that issue with Ys is because if its align downwards there is loss of larger particulates down the spot as flow is traveling from a more distance run?

Wouldn't constricting the flow to only 4" on the drop reduce the potential? At least from the tables, isn't 4" going to limit the CFM rate you could pull out of the pipe?

I would avoid flex in the main all together. Too much friction. Is there a reason you feel you need it? How much set do you need?

Yes, you are correct about the lateral.

CFMs and Pressure work together to create velocity. So, smaller duct increase velocity with the same CFMs. The static pressure of your fan overcomes the friction of the smaller duct, creating faster velocity. For example: if you use 10" for the drop, the CFMs would be the same, but there wouldn't be enough velocity to move the dust (4000 FPM I think). If you use 2", the fan won't develop enough static to overcome the friction. This is a very simplified example. Also you'll have a pressure drop going thru 4 then blowing up to 6, this will "slow" the air down.

[Rush Paul]

Two thoughts:

1. For D2 and D3, if you can run all the way to the tool with a straight pipe coming from your 45-degree wye off your trunk line, you avoid another turn in the pipe and save some friction loss. Of course, you end up with diagonal pipe on the wall, but the resistance savings was worth it for me in our setup here.

2. Remember that your exhaust is part of the total system, so be careful not to introduce resistance there. If you use any flex, then upsize it (e.g., 10" or 12" diameter). Another alternative is a straight muffler or a baffle box. The straight muffler can be 1x the diameter of your pipe, but a baffle box should have 4x the area. There are good examples at the Australian Woodwork Forum.

[John T Allen]

Thanks for the inputs, as my wife would rather object to just shooting stuff into a trailer, the cyclone helps in that regard. While I'd like to try the outside the shop version for the blower, I don't think that is going to be possible with town planning permits (attached structure) at least at this stage.

Option5.jpg

So here is an alternate thought incorporating some of the suggestions. Reading a little more around, it doesn't seem to make sense for a single tool user to drop to 4" for the drops as with this blowers CFM that would be the limiting factor. I had a look at doing the angle for the D2, but with the port where it is and the space I have I'm really tied to have the drop about there. But it did seem to make reasonable sense to gradually angle drop 3. I also modified the incoming section to the cyclone - basically by angling the SDD XL at 30 degrees (inlet is on the left), I can then get it off the wall enough to run the horizontal-Y to drop to D1, through a long 90, similar to D2, perhaps these are suboptimal, but stuck with the space. The longest run in this case is reduced by a few feet, so with a single tool usage the SP drop seems reasonable.

In terms of the outlet for the blower - so I want to avoid venting smaller than incoming to the blower then?

[Stan Coryell]

"Reading a little more around, it doesn't seem to make sense for a single tool user to drop to 4" for the drops as with this blowers CFM that would be the limiting factor."

I'm not sure I understand. If the pickup on the machine is 4", what are you reading that leads you to believe the lateral should be larger?

"In terms of the outlet for the blower - so I want to avoid venting smaller than incoming to the blower then?"

You should avoid a discharge that is smaller than 2x Diameter.

Do you know the Static Pressure and CFMs your blower is capable of?

[Rush Paul]

In terms of the outlet for the blower - so I want to avoid venting smaller than incoming to the blower then?

Yes. And if using any type of flex, go larger.

[John T Allen]

"Reading a little more around, it doesn't seem to make sense for a single tool user to drop to 4" for the drops as with this blowers CFM that would be the limiting factor."

I'm not sure I understand. If the pickup on the machine is 4", what are you reading that leads you to believe the lateral should be larger?

"In terms of the outlet for the blower - so I want to avoid venting smaller than incoming to the blower then?"

You should avoid a discharge that is smaller than 2x Diameter.

Do you know the Static Pressure and CFMs your blower is capable of?

This is based off reading the following page more than a few times. This isn't the only place I've read this (including elsewhere here see https://sawmillcreek.org/showthread.php?78081-6-quot-vs-4-quot-dust-collection-duct), but perhaps I am misreading.
http://billpentz.com/woodworking/cyc....php#pipe_size

'Unlike big industrial sites, most hobbyists should run the same sized ducting, fittings and hose right up to their machines. Don't do like many and run a 6" or 8" main trunk line then come off with smaller duct...'

Now while I'm reluctant to custom make fittings at the 6" size at this stage or alternatively by adding ports, I'm contemplating doing so. In which case the 4" branch would also make less sense I think, but I could be wrong.

Blower is rated to 2300 CFM (probably overstated compared to expected operation) and 16.7 Static Pressure (a blower similar to this: https://www.grizzly.com/products/gri...eller/g1030z2p).

[Stan Coryell]

Unless you change the 4" pickups to 6" I doubt it matters. If your blower can pull -16" and move 2300 CFM (or 20% less) you should have no problem pulling the CFMs required by the manufacturer of the equipment through 4" pipe. Whether or not using 6" will give you the best dust collection at a particular machine I can't answer. We don't size duct that way. If a woodworking machine has a 4" pickup, it tells me I need 350 CFM's. 5"= 550. 6"= 800. I would build the system from these numbers.

As far as your provided links: I only skimmed them, but I didn't see any recommendations based on facts.

[John T Allen]

Appreciate all the suggestions. For anyone reading this after the fact and wondering on approach - in addition to the guidance from Bill Pentz, I spoke to the folks at Blastgateco and their recommendation was to continue 6" to as close to the tool as possible. The only reason they stated that a 4 inch pickup might be more appropriate was if the blower CFM was lower/lower SP and hence in order to maintain full flow you dropped the duct size at further distances. For my case with short runs, 6" to the tool is the best usage (even if the tool has a 4" pickup - or in the case of the 17" bandsaw 2x4" pickups). Order is placed now, so will be working on the install next week.