Dust collection question

[JeffSmith]

I'm building a new shop - actually, the building is up, waiting for final electrical and a little bit of interior finish work before starting to setup shop. The shop is relatively small - 26 x 22. Because it's sitting on a side hill, there's a decently deep crawlspace available with about 5 feet of headroom on the lower end of the foundation. I've been toying with the idea of putting my compressor and dust collector (2hp HF with Wynn Env nano filter and cyclone separator) down there and eliminating the noise both produce from the working area. Also, eliminates exposed ductwork through the shop. Plenty of room to run ducting and piping for air where it will be needed.

Doing some homework, there seems to be a difference of opinion on whether or not the slightly negative air pressure that would be produced is going to be a problem. The shop is heated initially by electric radiators - a small woodstove will be added eventually, though. The DC is only used when using stationery tools - table saw, bandsaw, planer, jointer, etc (I rarely do any flatwork any longer, but new cabinets, shelving and work benches will be on the menu soon), when sanding on the lathe (probably the most frequent use) or cleaning up after turning.

I really wanted the compressor out of the shop, but in thinking it through, decided to move the DC as well.

Any one have thoughts on why it may not be a good idea? Other concerns I may be missing?

 

[Steve Worcester]

Well, if your DC is pulling 1000CFM out of your shop, where is it going to get it from to replace it in the shop? In a heated shop, it's worse because you are them pulling in cold air from the attic, leaks in windows/doors. For the compressor, if you have a problem with frost and freezing in your area, you could end up with ise in the lines. Additionally, if you plan to shoot lacquers and film finishes, you generally want to keep the air at a relatively close to shooting environment in temp and humidity.
I thought about these exact problems and bought a quiet enough Oneida cyclone and a Bel-Aire quiet compressor. But my choice was the attic and I had a decent budget.

 

[JeffSmith]

Steve - I was toying with the idea of building an insulated box for both DC and compressor. I could put in a return air plenum at the same time. Seems like it wouldn't need to be much more than 6 or 8".
Would that suffice? I seldom spray finishes...and we only rarely get below freezing.

 

[Gerald Lawrence]

Jeff the points Steve made may not be insurmountable if you do what you have suggested of sealing a room for them and return air. My DC is in the attic and I have return. The DC room is insulated but the air does get very warm there. Also to consider is that the compressor will have to be blown (to clear moisture ) periodically. Also intake air for compressor will be dusty if in the same room as compressor leading to clogs and dirt filling compressor filter. This is not to say you cannot do this just that there are things to consider.

 

[RichColvin]

I have a basement shop which is a walled off area of the basement. I recently moved my dust collector to be just outside the shop. The noise reduction is significant, and makes it much more comfortable when using the down draft bench I built for power carving. In fact, if is so nice that I am now in the process of moving the air compressor outside the shop area also !!

One consideration for Jeff is this : Consider putting your collection piping below the floor as you mentioned, but dump it into a dust separator (either a cyclone or Thien baffle). The discharge from the dust separator would then be fed into the dust collector.

As the majority of the dust will end up in the separator, putting that beneath the floor would make it easy to access for dumping.

 

[robo hippy]

Putting it down under might be a good idea. On any temperate day, no problem with venting to the outside. On any cooler day, you want to vent back into the shop. 1000 ft./minute out of an 8 inch hole will be a lot of wind.. 2 ft. sq. vent would be better, but still windy.

robo hippy

 

[JeffSmith]

I've got a cyclone separator in the system now. With the Wynn Env. Nano filter getting 99.999% of everything 0.5 microns and larger, not much escapes the system now. I'll make the return air plenum 2 ft2 to cut down the velocity, but I'd guess it's going to need to be baffled to keep the noise isolated. Otherwise, what's the point. The compressor is the real noisemaker. Maybe I'll need to isolate it in its own 'room'. There's a valve to drain the tank already in place, I'll run it to the outside.
Think I'll need to filter the return air? Might help keep the noise isolated.

I really don't want to vent directly outside. The shop is at the top of a ravine with a creek that runs to the Sound - it took a year to get approval from Natural Resources to get the shop built in the first place. I really don't want to have to go through that process again if I can avoid it.

 

[Mike Johnson]

A grated floor under the lathe with a plastic barrel to catch your shavings under the floor of the shop.
A side door outside the building to open and pull the plastic catch barrel from your basement.
Sweep your shavings into the grating and your floor is clean.
Let gravity do the heavy lifting!

 

[Bill Boehme]

Steve - I was toying with the idea of building an insulated box for both DC and compressor. I could put in a return air plenum at the same time. Seems like it wouldn't need to be much more than 6 or 8".
Would that suffice? I seldom spray finishes...and we only rarely get below freezing.

That's way too small unless you want a really strong wind coming through the return air duct. What's the reason for the box around the DC?

 

[Gerald Lawrence]

That's way too small unless you want a really strong wind coming through the return air duct. What's the reason for the box around the DC?

Bill I have a 20 X12 filter opening from my DC to shop and if the return is located away from work areas you will never notice it. As for the box probably not needed on DC with pleated filter, but possibly good for compressor if noise is bad. I would suggest maybe relocate to new area and then test for noise with the return filter installed.Sounds like he has a good DC setup.

 

[Steve Worcester]

Steve - I was toying with the idea of building an insulated box for both DC and compressor. I could put in a return air plenum at the same time. Seems like it wouldn't need to be much more than 6 or 8".
Would that suffice? I seldom spray finishes...and we only rarely get below freezing.

On my Oneida, it has a noise (exhaust) muffler and I think a 5" exhaust but does not have the bag on the exhaust end. So you could diffuse that by going larger, but it is still alot of air coming out regardless. At 1000 CFM, it would completely turn over my 9' ceiling 25x25 shop in 5 minutes. But it doesn't seem to be as disturbing in air movement as the number suggest.
What DC are you using?
As far as it being to big or small, don't recuse the outlet size, but increasing it I don't think is going to be of much value. If it is a bag dust collector, not a cyclone, the numbers get thrown off because the exhaust is though the bag.
As for the compressor, put an auto drain trap on it and as it starts up, it spits out the water in the trap. I would also look at a remote switch so it doesn't go on and off all the time. I would also recommend running Rapid Air . I ran the home garage setup and it is pretty good and easy to use.

 

[Steve Worcester]

A grated floor under the lathe with a plastic barrel to catch your shavings under the floor of the shop.
A side door outside the building to open and pull the plastic catch barrel from your basement.
Sweep your shavings into the grating and your floor is clean.
Let gravity do the heavy lifting!

We don't have basements, but three observations.
How do you find all the screws and stuff you drop on the floor, that go into the grate area?
And can a grated floor support multi-hundred pound lathe?
How do yu get the trashcan, that now weights a hundred pounds with wet shavings, out of the basement?

 

[Bill Boehme]

More importantly, how do you get 24" long wet streamers of wood to go through a grate? Shaving pile up knee deep around the lathe ... actually more around me than around the lathe. I use big push brooms and snow shovels to move the shavings. I can just imagine how much fun it would be down on my hands and knees unclogging a grate. But, as Steve said, we don't mess with basements in Texas.

 

[Michael Mendelsohn]

CAUTION ! ! !
In your original post you mentioned that you were adding a wood stove for heating. You then mentioned creating negative pressure by extracting air from the shop with the DC.

The negative pressure will suck the smoke and carbon monoxide from the wood stove back into the shop instead of out the chimney. If you are worried about dust in your lungs, you might consider the damage done by the exhaust of the wood stove.

 

[Steve Worcester]

CAUTION ! ! !
In your original post you mentioned that you were adding a wood stove for heating. You then mentioned creating negative pressure by extracting air from the shop with the DC.

The negative pressure will suck the smoke and carbon monoxide from the wood stove back into the shop instead of out the chimney. If you are worried about dust in your lungs, you might consider the damage done by the exhaust of the wood stove.

Good point, I would also highly recommend EVERYONE put a smoke detector/CO2 alarm in their shop

 

[hockenbery]

Good point, I would also highly recommend EVERYONE put a smoke detector/CO2 alarm in their shop

And a fire extinguisher class ABC

 

[Mike Johnson]

The 1st post mentioned having a 5 foot tall crawl space under the main level.
Years ago, I attended an auction at an old multi-level belt driven wood milling operation.
The milling operation was on several floors and some of the machines on each level had
large chutes that dropped shavings and wood scraps from the upper floors to the basement where
they would burn the shavings in a boiler system which would heat the facility and turn the main belt drive.
They let gravity do most of the heavy lifting for them. Located next to a river they also had water power
and the timber came from up river and finished goods would ship out on various river boats.

 

[JeffSmith]

Thanks for all the comments. I assume that as long as the return air mostly equals the air removed the negative pressure aspect is rendered null. That said, the suggestion to put CO and smoke detector is heard loud and clear - I hadn't thought of that. I do already keep extinguishers at hand.

Bill - the box has two functions - keep noise down and provide a little protection from the elements in the winter months. As for the grated floor, I had considered a slightly different arrangement with a trap door in the floor that would allow me to sweep everything into it. Close the door and it's all gone. But the most logical place to put it is close to the lathe, and that's directly over the smallest part of the crawl space (building is on a side slope - 5 foot crawl space area is on the 'down hill' side.

I'm thinking the return air can be directed under part of the work bench/cabinets that are on the immediate horizon to keep the return airflow under a little control.

 

[Bill Boehme]

The 1st post mentioned having a 5 foot tall crawl space under the main level.
Years ago, I attended an auction at an old multi-level belt driven wood milling operation.
The milling operation was on several floors and some of the machines on each level had
large chutes that dropped shavings and wood scraps from the upper floors to the basement where
they would burn the shavings in a boiler system which would heat the facility and turn the main belt drive.
They let gravity do most of the heavy lifting for them. Located next to a river they also had water power
and the timber came from up river and finished goods would ship out on various river boats.

That is probably the consummate example of trickle down economics.

Thanks for all the comments. I assume that as long as the return air mostly equals the air removed the negative pressure aspect is rendered null. That said, the suggestion to put CO and smoke detector is heard loud and clear - I hadn't thought of that. I do already keep extinguishers at hand....

Even an almost imperceptible negative pressure on the inside will lead to back-flow and your shop filling with smoke. Belching woodburning heaters aren't any fun. Simple things like chimney height, slope of roof, and wind speed can lead to a persistent problem. If your DC is exposed to outside air pressure that can create a big problem with using a woodburning heater. One of our gas water heaters is located in the garage, but building code required that it be enclosed in a closet with inflow air and ventilation from the attic and vented through a stack through the roof. One might think that isn't a problem, but the almost imperceptible pressure difference led to enough downdraft to persistently blow out the pilot light. Newer model gas water heaters are available with an igniter that helps to mitigate the problem as long as the downdraft doesn't blow out the main burner.

... Bill - the box has two functions - keep noise down and provide a little protection from the elements in the winter months. As for the grated floor, I had considered a slightly different arrangement with a trap door in the floor that would allow me to sweep everything into it. Close the door and it's all gone. But the most logical place to put it is close to the lathe, and that's directly over the smallest part of the crawl space (building is on a side slope - 5 foot crawl space area is on the 'down hill' side.

I'm thinking the return air can be directed under part of the work bench/cabinets that are on the immediate horizon to keep the return airflow under a little control.

Do as Gerald suggested and have a very large return duct. If your DC is exposed to outside air pressure even through a small leak in the enclosure then there will be a pressure differential that is going to present a potential backflow problem for a vented heater. Consider getting getting a better quieter DC that can be located in the shop.

 

[Steve Worcester]

Do as Gerald suggested and have a very large return duct. If your DC is exposed to outside air pressure even through a small leak in the enclosure then there will be a pressure differential that is going to present a potential backflow problem for a vented heater. Consider getting getting a better quieter DC that can be located in the shop.

Or a different heating method. DC might be cheaper.

 

[Raul McCai]

Put a fire alarm in there. That's all I'm going to say. I like those Fire alarms that are bluetoothed to each other. So if one goes off, they all lose their minds and start howliing. I would like to see an iteration of this where the alarms all know which one is the one that started it and tell you.