Dust Collector baffle question

[JimmyC]

I know, I know, I should know better than to ask a question about dust collection, but here it goes. This will be my set up so don't tell me that I need a cyclone, it's not in the stars at the moment.

I have a Grizzly 2hp DC, I will be using 6" HVAC pipe ( got it free ) and a Phil Thien seperator (also 6" inlet/outlet), but here's the catch, I want to blow it outside of my shop instead of using a bag/filter set up. The closest neighbor in the direction of the outlet will be about 1/4 mile away, but I still have people near me in the front so I am worried a little about the noise.

Here are my questions:

1) Is there a limitation on the length of the outlet pipe ? I would probably use 10' in length.

2) Is there any plans out there for baffles, and do they work well for knocking down the decibels, also would a baffle cause a back pressure problem ?

3) Has anyone here done anything like this with their set up, and how does it work ?

Thanks in advance.

[CarvedTones]

I was worried about my single hose A/C in the garage, as it pulls in outside air. It really hasn't been a problem. Your clothes dryer does it also. Not sure about the relative flow, though.

[JimmyC]

Originally Posted by AndyBarnhart

I was worried about my single hose A/C in the garage, as it pulls in outside air. It really hasn't been a problem. Your clothes dryer does it also. Not sure about the relative flow, though.

I agree Andy, with my shop almost 1300 sq/ft with a 12' ceiling I don't think that I would have a problem unless I was planing or jointing alot of wood, and for that I was thinking about putting a "Y" on the outlet so that I could switch of to an inside filter during extreme weather days.

On another note I was wondering about putting my DC outside. Does anybody have any idea how these motors and blowers would hold up outside under an overhang ?

Thanks,

[Alan in Little Washington]

Ok, Jimmy, just for you-

It will be easy, because almost all the correct answers have been posted here already! I will restate and expand on some.

1. Oulet pipe. No length limit, the shorter the better, no bends if possible, no flex, 6" minimum.

2. No baffle is needed, you want minimal restrictions. You can discharge into a dumpster, or like some folks into a tilt trailer box, so you can drive it away and easily dispose of it.

3. Muffler, likely not needed, but can be added at any time if you decide you need one. Motor and blower make most noise, sound exiting discharge pipe of 10' or so will attenuate quickly across lawn, through trees, etc. The filter shown by Tom should work well (again doubt you need it), I have seen those on airplane engines that had no regular muffler and minimal exhaust manifold- they do work well but can be a bit heavy.

4. I know of a couple of WWers who direct vent and use (1) no catchment into a swale (2) large bin/small dumpster (3) a trailer. All are happy, but all live in various shades of rural. If your have ever made it all the way through Mr. DC's website, Bill actually says the best DC system is one that direct vents with no cyclone, no filter, etc. Least resistance and best flow possible.

5. Unless you have an undersized HVAC or run the DC for long stretches, loss of heat and AC are not as much of a consideration as you might think. You'll have the "refrigerator effect*"- your shop walls, floor, ceiling, contents and machinery all have "thermal mass" that help maintain a constant temp. *When you open an upright fridge door, the cold air all falls out, but after you close the door, the fridge mass, walls and contents, rapidly cool the new air.

6. If your shop has a gas, fuel oil, or wood fired heater or water heater, and depending on how well your shop is sealed, discharging to the outside can cause reverse flu flow and draw exhaust gases including highly dangerous CO back into the shop. I had this problem in my VA shop and got a severe headache once when I forgot to open the window(s). I know, I know, that explains everything. Otherwise, unless your shop is extremely tightly sealed, providing a source for takeup air is not much of an issue for efficient DC operation.

7. I put my entire DC and cyclone outside in my VA shop since it was too small and the DC too noisy- I prefer keeping it outside to save my ears and shop space. You will need to protect the motor/blower from rain and rust, but that can be done easily with a little open sided (for cooling) shed. Except for a new coat of gray paint, I left the TFEC motor and cyclone at my old house totally unprotected. After almost 3 years the non-exterior grade ply top on the cyclone had started to deteriorate a little and there was some very minor rust on the motor / blower (see pic of old installation) which is still working great with my new cyclone in my new DC installation.

That's my story and I am sticking to it.

[JimmyC]

Alan thanks for the input, I see that even back in VA you had a thing for Delta Grey paint.

I still might go with the muffler, but I think that I may try it without first. I'm not rural enough to blow it to the ground but I may try to think of some sort of trailer set up. The heat loss idea seems to work out for me and I'm not too worried about a reverse of flue flow, yet. I guess the DC on the outside might work out well, except for maybe the sound.

once again thanks for the input.

[scsmith42]

Jimmy, there is a lot of great advice on this string; Alan's post in particular stands out.

Having planed a lot of wood, I've literally generated several dump truck loads of shavings, and this probably influences my thinking...

I would explore building a small "lean-to" against the outer wall of your shop, with a screened window between the lean-to and the shop. Make the lean-to long and wide enough to house your DC blower on one end, and to be able to back a small trailer that has sides all the way around (such as a garden trailer) and park it from the other end. Totally enclose and insulate the lean-to with doors on one end. Make it reasonably tall - say 8' or so at the ceiling.

Putting the DC in the lean-to should dampen all of the noise that you need to dampen. Skip the filters -probably not needed. Direct vent the outlet pipe to dump straight down into the trailer, with a screen between the pipe and the top of the trailer.

When you're running the DC, open the window between the shop and the lean-to. This allows the air to return.

I'm building a "large scale" version of this concept into my wood processing building, albeit with a larger blower and dump truck...

It's quiet, effective, no loss of conditioned air, and makes it easy to dispose of the shavings.

[JimmyC]

Scott,
I have a 10 x 20 lean-to on the side of the building and that's what I'm planning on setting the DC under, but I'd rather not close it in because I want to eventually use the area for air drying lumber. I like the idea of a window over there and I've got to figure a way tosound insulate. Thanks for the ideas.

I want to thank everyone for their comments so far it has really got me thinking.

[Bas]

Originally Posted by scsmith42

When you're running the DC, open the window between the shop and the lean-to. This allows the air to return.

Scott, it sounds like an excellent design. But, won't having an open window allow any fine dust to come back into the shop? Not a huge issue when planing, but table saw, drum sander etc. produce lots of fines.

A more sophisticated solution would be to vent into this lean-to, but use a heat exchanger to recover any heating/ cooling! But now we're getting a little too complicated.....

[CarvedTones]

I don't understand why you even need a DC for planing.

[JimmyC]

Originally Posted by AndyBarnhart

I don't understand why you even need a DC for planing.

Don't you have a YMCA thing to go to.

[CarvedTones]

Yeah, I got one eye on the clock - about 30 minutes until I head home and then out...

[golfdad]

Jimmy...........I have the same Dc would like to see yours when your done............Im in Clayton

[JimmyC]

Originally Posted by golfdad

Jimmy...........I have the same Dc would like to see yours when your done............Im in Clayton

Dirk,
I don't know when I'll get arouind to it, but I will definitely let you know.