Replies

1. 
   AntzyClancy | Feb 16, 2006 07:05pm | #1

   
   http://billpentz.com//woodworking/cyclone/Links.cfm

   Have you read this?  If you are serious about dust collection, you can educate yourself.

   Here is an excerpt on duct size:

   Always use the largest diameter duct that your blower can use with the least number of restrictions. If your ducting is too small, then it instead of your blower defines the CFM that your system can provide at your machines to pick up the dust. If your ducting is too large you might not maintain the airspeed needed to keep sawdust and chips from building up and blocking your ducting. You need about 3000 feet per minute (FPM) airspeed to keep light sawdust moving horizontally and about 3700 FPM to move it vertically. Air engineers target their designs to maintain about 4000 FPM to keep the dust entrained (moving). FPM is simply CFM divided by the area of the duct in square feet instead of inches (144/sq. in.).

   Here is an excerpt on shop vacs:

   Most small shop woodworkers start their dust collection with a shop vacuum. A vacuum moves a small volume of air at a relatively high pressure. Vacuums do an excellent job for cleaning up small areas. Vacuums do not move enough air volume to be good for capturing dust from machines that emit dust over a larger area. Most vacuum filters are too small and too open, so spray the finest unhealthiest dust throughout our shops. Unless you replace the stock filter on your vacuum with a top quality fine filter, almost all vacuum filters freely pass up to 50-micron sized particles making them ?dust pumps? that keep the most dangerous fine dust circulating.

   It is likely that your shop vac does not really move enough air now, so going to a larger duct size would only make it worse.

   Good luck,

   Todd

    

1. 
   Jim McDonald | Feb 16, 2006 11:01pm | #2

   Thanks Todd, I'll be sure to check the recommended site. I don't have room in my existing "shop" a 10 x 16 shed, (see retirement shop 2/15) but a complete dust system is on the drawing boards for the new shop. I'll hopefully get started on in the spring. I had thought tht if it would be benificial to the existing shop vac system, I'd change the ducting size now rather than later, but I'll hold off for now...spend the cash on some new tool that I'll hve to figure out  how to make room for. 

   Thanks again for the direction!

   Jim

   Edited 2/16/2006 3:22 pm ET by Jim McDonald

   Edited 2/16/2006 5:55 pm ET by Jim McDonald