Andrew Duncan
03-19-2008, 1:23 PM
When I built my shop 10 years ago, I didn't know much about dust collection.
I put 4" D&S PVC pipes under the floor with outlets around the shop for the various tools. The 2 HP DC with standard bags was put in a closet sealed from the rest of the shop except for 2 20"x20" openings for filters (for return air to the shop) and a door to the outside. Thought I was a genius for figuring that out. It worked just OK. Not a genius.
A few years ago, I upgraded the top bag to one of those pleated filters as I could still see some very fine dust coming through the filters back into the shop. A bit better. As an interim measure, I started opening the outside door when using the DC and things again improved, but only incrementally. Then I added 2 of the small Jet air filtration units inside the shop; again an improvement, but not there yet. It seemed like I still needed to change the whole DC set up if I wanted to get where I wanted to be. New properly sized ducts, new cyclone based DC, etc. Big money.
Then I read what Keith Outten (and others like Steve Clardy) had to say about blowing the dust outside. Off with the pleated filter, off with the bag. 12 feet of stove pipe, some duct tape and a hole in the wall later, it's DC heaven. I just finished boxing in the outside 6 feet of pipe to protect it, supported by a pair of cedar trunks laddered together and put in some post holes. Without the back pressure on the system, the dust seems to just disappear. Some of the closed blast gates now hum with the improved suction. I'd guess a 3 or 4 or more times improvement in air flow. Cleaning up the bench, by mistake I sucked up a pencil about 6" from the hose end. I found some pieces of it about 15 feet from the shop!
So, Keith, my lungs and I both say thanks.
I put 4" D&S PVC pipes under the floor with outlets around the shop for the various tools. The 2 HP DC with standard bags was put in a closet sealed from the rest of the shop except for 2 20"x20" openings for filters (for return air to the shop) and a door to the outside. Thought I was a genius for figuring that out. It worked just OK. Not a genius.
A few years ago, I upgraded the top bag to one of those pleated filters as I could still see some very fine dust coming through the filters back into the shop. A bit better. As an interim measure, I started opening the outside door when using the DC and things again improved, but only incrementally. Then I added 2 of the small Jet air filtration units inside the shop; again an improvement, but not there yet. It seemed like I still needed to change the whole DC set up if I wanted to get where I wanted to be. New properly sized ducts, new cyclone based DC, etc. Big money.
Then I read what Keith Outten (and others like Steve Clardy) had to say about blowing the dust outside. Off with the pleated filter, off with the bag. 12 feet of stove pipe, some duct tape and a hole in the wall later, it's DC heaven. I just finished boxing in the outside 6 feet of pipe to protect it, supported by a pair of cedar trunks laddered together and put in some post holes. Without the back pressure on the system, the dust seems to just disappear. Some of the closed blast gates now hum with the improved suction. I'd guess a 3 or 4 or more times improvement in air flow. Cleaning up the bench, by mistake I sucked up a pencil about 6" from the hose end. I found some pieces of it about 15 feet from the shop!
So, Keith, my lungs and I both say thanks.