Connecting 6" PVC to Dust Collector's 8" Inlet

[Cooper Anderson]

I just bought a 3HP JDS Cyclone with an 8" inlet. I am planning to use 6" S&D PVC for my main line. How do I connect the 8" inlet on the dust collector to the 6" PVC?

[John Lanciani]

Either a plywood donut or a tapered duct adaptor (sheetmetal) will work. The adaptor may require some minor fiddling to get it to mate up to the PVC.

[Brian Williamson]

http://bestmaterials.com/detail.aspx?ID=19310

The above type of connector gives a good seal, OK flow properties, a little wiggle room, and some vibration dampening all in one.

Be sure to take measurements of you fittings prior to ordering. There are a lot of combinations available. The one shown in the link may not be exactly what you need.

[Art Mann]

I hope you are aware that the performance of your system is going to be seriously compromised by using the smaller pipe.

[Cooper Anderson]

Art - are you suggesting that I need an 8" main? My shop is in my garage and I'll never use more than one machine at a time. Don't you think it will still be effective with a 6" main and limited use of flex hoses?

[Cooper Anderson]

That looks promising. Thanks for the link.

[Wade Lippman]

I had a 3hp JDS and ran 15' of 5" flex to the machines. It worked fine. Certainly I lost a lot of the suction, but enough remained.

OTOH on my current 3hp Grizzly, I ran 8" to the ceiling and then split to 2 6" lines. I would recommend that over just reducing to 6" immediately.

[David Wong]

I have a 2-1/2hp Oneida super gorilla, with a 7" inlet. I use a 20ft 6 inch flex to one machine at a time in my small 2 car garage. Using one machine at a time (bandsaw or 12" j/p), I seem to have plenty of suction. I should cut the flex down since it gets in the way, but I have just been procrastinating. The suction from the cyclone is overkill for my usage.

The problem with laying out permanent ducting in a residential garage is the overhead door gets in the way.

[Chris Parks]

I hope you are aware that the performance of your system is going to be seriously compromised by using the smaller pipe.

That is not so for the average user. The standard recipe for good dust collection is 6"/15", if you want more use a bigger impeller and then a bigger main duct and leave one overhead 150mm duct open at all times if only using a single machine. This has been found to work very well for a hobby workshop, the open duct continually scrubs the air.

[Cooper Anderson]

Do they even sell 8" S&D PVC? I've never seen it.

[Jim Andrew]

Those fernco connectors are great! they keep your pipe from vibrating with the dust collector.

[Mike Heidrick]

Maybe go 8" to two 6" Wye?

[Art Mann]

Art - are you suggesting that I need an 8" main? My shop is in my garage and I'll never use more than one machine at a time. Don't you think it will still be effective with a 6" main and limited use of flex hoses?

Good enough is good enough. I am sure it will do the job for you. If I were choosing a new dust collector for such circumstances, I would have selected a smaller unit as that one will not be used near it's full capacity.

[Cooper Anderson]

Good enough is good enough. I am sure it will do the job for you. If I were choosing a new dust collector for such circumstances, I would have selected a smaller unit as that one will not be used near it's full capacity.

That makes sense. This certainly isn't the first time I've been accused of over engineering a solution. :D Thanks for the comments.

[Cooper Anderson]

Maybe go 8" to two 6" Wye?

That would be the best answer, but where would I buy a 8" to two 6" wye?

[Brian Hale]

Use a piece of 8" galvanized hvac duct, roll one end to match the 6" duct and the other to match the 8" duct, drill and pop rivet and apply silicon caulk or aluminum hvac tape to seal it. Fernco couplings on each end and you've a smooth transition that won't transmit vibrations.

[Wade Lippman]

That would be the best answer, but where would I buy a 8" to two 6" wye?

I've got two of them. I have a 8-8 wye, and from there two 8-6 wyes. Just check with a HVAC shop. How you get from that to plastic, I have no idea; I went metal all the way.

[Jim Andrew]

Cooper, don't take too much from this thread. You need to go to Bill Pentz website and do some reading. Google Bill Pentz. Last time I did some reading, he was saying a 6" system with the 5hp 16" impeller cv would be strong enough to keep your shop healthy for you. So just use the 8 to 6 fernco and 6" pipe, you will have a good system.

[Brian Hale]

Bills site is a massive source of information and a worthwhile read.

It is suggested that, if at all possible, you ahould use a minimum of 4' of straight pipe leading into the cyclone inlet. Making an abrupt change from 6" - 8" right at the inlet will cause a lot of turblance going into the impller which will have significant impact on it's performance. The smother the transition the better.

[Mike Heidrick]

Make your own

Found this site a long tima ago. This was the comment from a lumberjocks member.

Here’s a cool app that lets you print out a template that you can wrap around each pipe and cut out the exact holes needed to join the 2 pipes together.
http://www.harderwoods.com/pipedocs.html