dust collection shed - any thoughts?

[Mike in Mystic]

Hi everyone,

I'm about decided on building a small enclosure behind my garage shop to house my dust collector and air compressor. I want to free up space and reduce noise and improve air quality, if possible.

I've never built any kind of construction like this and am not really sure the best way to approach it. If anyone here (and I'm sure there must be several) have built these types of structures, I would be very grateful to hear what you did and any tips/instructions you would offer to me before I start.

Some particular things I'm interested in are whether or not you returned the air back to the shop. My shop is insulated but not heated, so it get's really cold in the New England winter where I live. Also, is it acceptable to just build a secondary structure and then simply cut a hole through the garage wall and run a bit of duct in order to tie in to the dust collector vs. attaching the structure directly to the outside wall? Obviously, if it isn't a big deal, I would rather make this "shed" stand alone and not mess with the garage.

Thanks for your help!

Mike

[Andy Dingley]

My inclination would be to not do this.

- A return path for air is a return path for compressor noise.

- Returning the air also means sealing the shed, lest the draughts when not extracting make things colder than the heat saved by the returned air.

- You're usually pulling dust extractor air from near floor level, where it's coldest. This is the least valuable air to hang onto.

- I don't think you need it (although the most wintery I've been to Boston was in November, and when I went in April I got sunburn !)

Even if you do go this way, you're only going to _want_ to return the air for maybe 4 months of the year, the months you're least inclined to be out in the workshop. So make it configurable either way - put a shutter on the return duct and leave it blocked for much of the year.

[Mike Myers]

Mike, weather you attach the shed or not, you should return the air to the shop. The air your removing will have to be replaced somehow. If you don't return it thru duct work, it will replace its self thru loose windows, doors, cracks ect. You may want to heat the place some day. Put a filter on the return air duct to reduce dust. If you are concerned about noise, you can insulate the duct on the INSIDE. Duct insulation is available at HVAC suppliers or have a sheet metal shop do it for you. Make sure you size the duct so the insulation doesn't restrict the air. Making the duct oversized will slow the air down and serve to quiet the rushing sound as the air leaves the duct. Mike in LC PS By the way, My wife and I visited your seaport last Oct. Wonderful place. Of course we had to stop for pizza.

[Gregory N. Latiak]

Mike,

I have built things like this in industrial situations, so some of my experience may apply to your situation.

1. The compressor -- these things are usually in a corner away from everything else, although it is best to keep it above freezing due to water buildup in the compressed air. This may not be a problem if it gets plenty of use -- compression heats the air, so things stay warm of their own accord. Otherwise, no issues, just keep it dry.

1. Most of the dust reclaimation I have done has been with toxic or corrosive chemicals, so returning the air to the shop was not an option. With wood dust that is probably not a real issue (but there will be fine particles blowing through the bag...). The blower will probably not care if it gets cold, so where it lives should not be an issue. I expect that you will have ductwork inside the shop to collect the contaminated air, then shove it through a centrifugal seperator and into a bag house of some sort. Yes, this can get pretty noisy. Industrial applications just park all this stuff outside in a shed -- often on the roof for convenience. The suction line can just be punched through the wall. But you have to deal with the makeup air and/or the return. I would just have an intake grill of sufficient size with a washable filter to screen out the bugs and low flying birds -- letting air in from outside. I presume you are switching this system with your power tools. You could bring the bag house air back in through a big duct with insulation inside to dampen the noise -- it is tricky to get right but doable. But I wouldn't do that simply because of the real fine particles that just blow through the bags.

The sheds for this stuff are nothing fancy, just something to keep the snow and rain away. And no point making it air tight, may even need an exit grill.

Hope this helps.

greg

[Edwin Pawlowski]

Hi Mike, Any "news" yet?

My plan was to add a shed on the back of my garage, but other things came up and it will probably wait until spring.

In my case, adding on the back of the garage means building three walls instead of four. I'll use the same siding as the garage. My intent is to put the DC in there along with other accumulated non-wood related stuff. The DC will suck some air from the barely heated garage. I'm going to add in a vent with a filter. That will allow air to return, but keep out the unwanted dust particles. While it will make for more total heat loss than I have now, it will be better than the 100% loss of no return.

My shed will not be visible from the street. It is a detached garage and the addition will be 10 x 12. If all you are doing is putting the DC and AC in there, it can be pretty small keeping heat loss minimal. It can also be a "feature" if you decide to sell in a few years. The new buyers may like having a place for the trash cans. Ed [e-mail]

[Rico]

If the garage isn't insulated and the addition is, then you have effectively insulated part of one wall of your garage. A reduction of heat loss.

If you vent all the filtered air back into your shop, all the work the blower did on the air is returned in the form of heated air. Another small gain. The amount of heat added to the air is essentially the equivalent of the actual shaft horsepower of the motor as you are using it. If you have a 2 hp motor and your blower actually loads it to a 2 hp load, it's close to a 1500 Watt heater.

Rico

[Mike in Mystic]

Hi Ed,

Yes, there is news, indeed. His name is Charles (Charlie) Michael Logman and he was born on 8/21 at 5:01 PM, 9 lb. 0.4 oz. and 20.5" long (that's just under 1' 23/32" hehe). He's doing great (and I haven't been in the shop in a week and a half and am not sure when I will get back!).

I see what you mean about the heat loss as I'm in the exact same type of situation as you. Even with that 80,000 BTU propane heater I got this last winter, I don't know how much heat was being held in the shop. But, I guess if I start pulling 1200 cfm of hot air out of the room, it won't be any warmer.

My problem is that the garage has a dormer roof (I'm not really sure on the terminology, but I think that's what it is). Basically the front of the roof has a different pitch than the back adn the back slope comes very low to the ground (something like 5 feet or so at teh outside edge). So, I don't think I can really build anything attached to that wall without ending up with something pretty bizarre looking. I was really thinking of pouring some kind of concrete slab for the DC and AC to sit on and then building some kind of "temporary" enclosure so if/when we move it won't be tough to just take the thing down and bury the concrete slab hehe.

I'm not sure if the compressor will do too well in an uninsulated area, though, as some of the responders pointed out. The main thing for me is to get the DC outside so I have more room and then it should be easier to run some PVC and improve my dust collection. At present, after 2 or 3 weeks of working my shop is throughly covered with dust, even though I use the DC all the time.

Anyway, I don't think I'll get to this project until next spring either, unless something very miraculous occurs and SWMBO decides I can leave the baby's bodily function maintenance entirely up to her hehe.

Let us know how things go when you get to this project, maybe I can adapt some of what you learn or vice versa.

Mike

[Morgans]

Most ALL commercial users have the air compressor outside. Good reason. That is where they belong.

[Silvan]

Not much chance of that in this day and age. I just deleted my long post. I didn't want to scare you. :)

I have mixed feelings about the baby days. Good stuff, bad stuff... Sometimes I think having a third wouldn't be that bad, and other days I'm realllllly glad that's no longer supposed to be feasible, and that thing we had to sign about there being some out there chance of the sterilization procedure spontaneously reversing itself after 10 years has me a little edgy some nights.

Enjoy the baby. There's no other experience quite like it. That's for sure... :)