Dust Collection Setup Questions

[james reinke]

I have a 2HP Harbor Freight dust collection and have some questions about whether or not to vent outside instead of purchasing a canister filter. Heres my situation and setup. I have a 1 car unheated detached garage that I'm using for my part time hobby diy wood shop. At the back end of the garage is where I would like to vent outside if I choose to go that route. My blower is mounted to the back wall of the garage and would like to vent out there. The exhaust opening on the blower is facing torwards the front of the garage so I would have to use flexible hose and would have to be turned quite a bit to get the hose to the back wall again. By my garage door (at the opposite end), I have a service door that the bottom part of the door was installed a doggy door with a single flap so I know that air can get in, or escape through this not well sealed opening. The garage has no windows so if I go the route of venting outside, I would have to cut a hole in the back wall of the garage and I was thinking possibly using a dryer flap opening that only opens when the DC is on. I also have to note that my garage is not insulated at all, just drywall up around the garage. During the winter months I use a kerosene forced air heater that is by the garage door (front part of the garage), and blows torwards the back. My DC system I am setting up is with 4" pvc sewer pipe .
I have done some reading on the forums but dont seem to come up with any answers to my specific questions. With my setup and situation, do I have to worry about backdrafts, or the possibility of a fire, explosion with using my kerosene forced air heater? My setup before I was using a shopvac with 1 1/2" pvc that worked ok at best but am looking for setting up a little better system. With my previous system, I could run the heater and the shopvac with no issues. Also, if I decide to vent outside, if I understand correctly, I wouldn't need a filter or bag with this type of setup. Just trying to find out what the advantages and disadvantages to venting outside would be with my current situation and setup.
Thanks in advance for all feedback and opinions.

[Brice Rogers]

I too have a 2 HP Harbor Fright dust collector. I mounted it on an outside wall up high. I also made a Thien baffle. That helps about 98 or 99% of the dust/chips/chunks to be captured in a 50 gallon metal trash can. I vent the rest outside. I oriented the DC such that it blows DIRECTLY outside. So, I don't understand your comment that the output is oriented facing forwards. Why can't you rotate it 180 degrees? I too use a dryer vent flapper valve (5" IIRC). It works great.

I would strongly suggest that you employ some sort of separator though. You don't want strings of shavings or chunks getting to the inlet to the DC and getting stuck. It'll jam up in a "New York minute".

But I can't really address your concern about negative pressure or back drafts. I strongly suspect that you won't have a problem. This is based on my perception that it is similar to a torpedo heater and/or it draws its air from inside the garage and exhausts inside the garage. If your heater is taking in outside air, then my opinion is wrong. If your kerosene heater is exhausting directly outside, then there is a chance of a backdraft. But if it is a torpedo type of heater, when you're running the dust collector, the pressure on the inlet and outlet of your kerosene heater will be the same pressure, so it should NOT cause a problem. If you are exhausting the kerosene heater outside through a pipe, you could have a backdraft issue. It could be corrected by supplying a make-up air vent from the outside to the heater. In any case, I'd suggest that you prove that to yourself by turning on the kerosene heater and then turn on the dust collector and see if there is any effect.

[Alex Zeller]

What ever you blow out of the garage it'll need to be replaced with air sucked in. Obviously in the winter it'll be cold air being sucked in and it could be dirty air, how cold really depends on where you live. Then you'll have to deal with the dust you blow out of your garage. If you don't mind it being blown on your lawn or the back of your garage getting a coating of dust. Adding a dust separator will help. My neighbor has a large four 55 gallon can collector that's too tall for his shop. In the winter he hates to use it because of all the heat he looses so he broke down and got a smaller one that with a filter to avoid loosing all that heat. Temperatures in San Diego are much more favorable to just blowing it outside than in the frigid north.

[William C Rogers]

I exhaust outside. If you only heat your shop when working it could be a heat problem exhausting outside. I heat my shop 24/7 with in floor hot water. Therefore everything is to temperature. My make up air is from the ceiling gable vents. This is a mix of rising heated air and outside air. I also have a drop ceiling below the gable vents with openings for air intake. I can run my 3hp DC 8 hours with a max temp drop of 2 degrees even in the coldest temperature. It really depends on your shop if outside exhaust significantly affects your temperature. With a filter you need to clean and what the filter doesn’t catch is in the shop.

[Brice Rogers]

What ever you blow out of the garage it'll need to be replaced with air sucked in. Obviously in the winter it'll be cold air being sucked in and it could be dirty air, how cold really depends on where you live. Then you'll have to deal with the dust you blow out of your garage. If you don't mind it being blown on your lawn or the back of your garage getting a coating of dust. Adding a dust separator will help. My neighbor has a large four 55 gallon can collector that's too tall for his shop. In the winter he hates to use it because of all the heat he looses so he broke down and got a smaller one that with a filter to avoid loosing all that heat. Temperatures in San Diego are much more favorable to just blowing it outside than in the frigid north.

You're right that San Diego temperatures are very mild. In fact, during the winter I don't heat my workspace. Occasionally, I'll use a radiant electric heat pointed towards me.

But if I'm roughing a bowl (almost always green wood) and throwing wet chips 5 to 10 feet away, I don't bother running the dust collector. But I wear a mask.
If I'm turning a bowl with a bowl gouge and tossing chips 2 or 3 feet away, I don't bother running the dust collector. But I wear a mask
If I'm finish turning (e.g., using a negative rake scraper) or sanding, then I turn on the dust collector (and wear a mask).
If I'm vacuuming up the floor, then I turn on the dust collector and wear a mask.
I spend more time roughing and turning than I do sanding or vacuuming.

I'm wondering if others, in cold climates are running their dust collectors when they rough or turn? I find that the majority of the chips and particles are going 180 degrees away from the suction head.

[Ricc Havens]

Hey James, I can't provide any answers from personal experience but you may want to also ask your question in the forum on the main page called "Workshops". they do a lot od discussions on dust collector set ups as it's a more general workshops forum than specifically turning. But, maybe those guys can provide some more input about your concerns on negative pressure and other questions. That's the forum I got a lot of help from when wanting to make a homemade remote switch for my dust collector that was less expensive than buying the Long Ranger brand of remote.

Good luck
Ricc

[Randy Heinemann]

I have always chosen dust collectors that filter and recycle the air back to the shop. I have a basement workshop so that is part of the reason this makes sense. If you do that, however, you need to make sure that your filter is a high quality HEPA filter so that you aren't returning the finest particle to the air in your shop; namely the size particles that are potentially the most harmful to your lungs. I have a cyclone with a HEPA filter with a hood over my lathe. In addition, I have an air cleaner and wear a powered mask while turning and using other other powered tools, whether they are connected to a dust collector or not. I realize that HEPA filters are expensive and some will say this is excessive, but feel my lungs are more important. At this point, while I'm sure some dust does escape, there is very little on the floor or work table tops, so most of it must be collected. So, collection inside is not a problem as long as you are willing to spend the money on HEPA filters for your dust collector.

[Alex Zeller]

You're right that San Diego temperatures are very mild. In fact, during the winter I don't heat my workspace. Occasionally, I'll use a radiant electric heat pointed towards me.

But if I'm roughing a bowl (almost always green wood) and throwing wet chips 5 to 10 feet away, I don't bother running the dust collector. But I wear a mask.
If I'm turning a bowl with a bowl gouge and tossing chips 2 or 3 feet away, I don't bother running the dust collector. But I wear a mask
If I'm finish turning (e.g., using a negative rake scraper) or sanding, then I turn on the dust collector (and wear a mask).
If I'm vacuuming up the floor, then I turn on the dust collector and wear a mask.
I spend more time roughing and turning than I do sanding or vacuuming.

I'm wondering if others, in cold climates are running their dust collectors when they rough or turn? I find that the majority of the chips and particles are going 180 degrees away from the suction head.

I get the impression that your temps don't drop down to -40 in the dead of winter, lol.

I only run the DC when sanding and I try to do as little as possible, I try not to apply finishes in my shop so I don't do much finishing in the winter months.