DC system complete....observations...and another recording

[Jameel Abraham]

Just finished up my DC system today. Well, I still have a few tools to hook up permanently, but all the main feeds are run and all blast gates in place. I followed Ed's recommendation not to caulk or glue the joints, but only to screw the joints together. And I only did that where necessary (a place where I thought there might be some weight or stress on a joint), just a handful (may 10) spots. I made sure the duct was shoved all the way into each fitting. That seals it up quite well. I only found about three places where I could hear air rushing (rubbing your finger around the joint will tell you where to caulk) so I caulked those places and the sound instantly abated. And not even all the way around the joint, maybe 18" total caulk for the whole system. Nothing that will cause any headache when I make changes. There was however one place that needed caulk all the way around. Where the duct entered my pivoting blast gates on the downstream side (the upstream is not affected since the gate removes that side from the equation). These were hissing quite a bit, but a quick caulk all around sealed them up perfect. The caulking here does not negate disassembly, since the whole gate is bolted together and taking them apart is quite easy. I still have to put the whole system to work on a project, so we'll see how it performs in the coming months.

About the recording. The system with all the ducting is quieter than with just the closet. Of course once you open a gate, it gets kinda loud with the rushing air sound, but it depends on which tool and the shape of the inlet. Some are very quite. Others like the planer are unbearable. I must get a new planer one of these days. A Shelix head would be fantastic right about now....

http://www.khalafoud.com/media/ClearVueSoundTest_Jameelpart2.mp3

 

[r j cedar]

.......
The system with all the ducting is quieter than with just the closet. Of course once you open a gate, it gets kinda loud with the rushing air sound, but it depends on which tool and the shape of the inlet. Some are very quite. Others like the planer are unbearable. I must get a new planer one of these days. A Shelix head would be fantastic right about now....quote]

If you get the machine quiet and now want the quiet the blast gate noise, what can you do? If you have excessive cfm, relative to what is needed to get the dust, what about opening another gate somewhere else to let more air into the system and decrease the cfm at the noisy tool? Does that work?

Basically I am wondering if one can adjust cfm to quiet noise? I am looking to make my shop as quiet as possible. Duct collector in closet, with return air baffeled yes, but what about the notion of excessive cfm and opening up a gate to bleed off the extra air and decrease noise in the shop at the tool?

 

[Matt]

Reducing Cfm

Reducing Cfm

I do that when i use my 4" lines because those are loud but not louder than the machine I am running and that's the only time it's open anyway...I mostly do it because i am using 2 of them and tired of opening them. Anyway it does reduce the noise.

Matt