Replies

1. 
   zolton | May 18, 2009 02:31pm | #1

   Paul,

    That's news to me. I've got 30 gauge ducting throughout my dust collection system (powered by a Penn State cyclone, a smaller one).

   I've heard that more powerful systems can "collapse" thin ductwork. So far that has not happened to me, and I've made about every error there is to make in terms of not having a blast gate open when I fired up the cyclone.

   So, I'd have to say it works in my situation. Way, way less expensive too...

   Zolton

   If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon

2. 
   bd | May 18, 2009 02:34pm | #2

   A friend & I just bought all the equipment out of a cabinet shop that was closing down after about 30 years in the business. All of the duct work I got from them was 30 ga. Their dust collector, while being a large industrial type unit, was only 2 hp. 30 ga apparently worked fine with that for years. May make a difference if your dust collector has a lot of excess capacity over what you normally use. However, the 30 ga seems plenty rigid IMO.

3. 
   forestgirl | May 18, 2009 05:39pm | #3

   The main reason I see offered for heavier gauge is the possibility that if you accidentally have all your blast gates closed, the ducting could collapse.  I've always considered that, for my system, a highly unlikely event.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 
   
4. 
   Buster2000 | May 18, 2009 07:07pm | #4

   Paul,

   I went through this last fall. I upgraded to a 2HP cyclone in a new shop. There is a posting on another forum (Woodnet?) in which a guy shows his collapsed system. So it does happen. If memory serves me correctly his was a 5hp. I figured for the marginal cost why risk it?

   The straight pipe in my system cost me less than $100, which is 26 gauge. I purchased most of it at a local mechanical contractor, which was good as they were able to provide me with 4' lengths. The real cost was in the fittings, 6x6x6 t's were $20, blast gates were $15...

   Anyway, good luck.

   Buster

5. 
   Parke | May 18, 2009 07:33pm | #5

   The gauge of the steel depends on the vacuum created by your exhaust fan, the size of the duct & the distance to reinforcing (a connection counts as reinforcing).  Ductwork for an exhaust system typically needs to be heavier because exhaust systems create higher vacuums & pressures than HVAC systems.  One reason for this is that vacuum systems convey the air at higher velocities so the ducts will not clog with what you are conveying (i.e. saw dust).  More vacuum is needed for higher velocities.  I would certainly go with the recommended gauge; I've checked my resources and ducts up to 7" diameter and a vacuum of 4" to 7" WC require 24 gauge.  I would not recommend anything lighter than 26 gauge.

6. 
   Jamie_Buxton | May 19, 2009 03:45am | #6

   My cyclone ducting came from Home Depot, so I guess it is 30 guage.   It hasn't showed any signs of collapse.

1. 
   Buster2000 | May 19, 2009 03:57am | #7

   Home depot does carry higher gauge stuff. It's in 3' foot lengths.

1. 
   Jamie_Buxton | May 19, 2009 05:13pm | #8

   This is longer -- six or eight feet, IIRC.

7. 
   Y1RET | May 20, 2009 01:54am | #9

   I bought my straight ducts from a HVAC supplier. It came in 13 ft lengths, so I fewer joints, it is thicker gauge and cost less than what the big box sells.  

8. 
   gpssam | May 20, 2009 09:09pm | #10

   I have a 2hp Oneida Gorilla. My duct work is a mix of good, bad and ugly. I bought the good stuff with my collector. The bad and ugly came about when I moved and needed to re-configure my shop lay out. Some of the latter HVAC stuff is quite thin. I have sealed up all seams with metal tape, so I know that I have a good tight system. It uses less electricity with all gates closed, so I always close the gates when the system will not be used for brief periods of time. I have not had any problems with any of the duct work.