HF Dust Collector With Home Built Separator; Will This Work?

[Aleks Hunter]

I just cannot wrap my mind why people think it is better to err on the side of risk than on the side of caution. Especially when caution costs less than $10 more than risk. References to a "typical" are or as Dan put it above "Hobby" shops are meaningless. Hobby shop could mean two saw horses and hand tools in the garage at one extreme to my shop where I can fill a full ton dumptruck with sawdust in a day. When someone is asking advice, and you have no idea of their experience level, no idea of the equipment they have, and no idea of how it is installed, and no idea of the kinds of wood and other combustibles may be present (are they spraying volatiles without ventilation in the same enclosed space? (please do not try to argue that no one ever does)
I've seen too many people suffer lacerations, contusions, concussions, amputations and burns because the ignored simple, cheap safety precautions.

[Michael W. Clark]

So measure your grain loading and look up the MEC for what you are collecting and see if you are at risk. I said bonding plastic duct was a good idea. Typical industrial dust collection systems do not approach the MEC in the duct. If they do, most industrial fabric collectors would not handle the loading.

The loading generated in a hobby shop would be a cake walk for a pulse jet collector.

[Dan Hintz]

I just cannot wrap my mind why people think it is better to err on the side of risk than on the side of caution. Especially when caution costs less than $10 more than risk. References to a "typical" are or as Dan put it above "Hobby" shops are meaningless. Hobby shop could mean two saw horses and hand tools in the garage at one extreme to my shop where I can fill a full ton dumptruck with sawdust in a day. When someone is asking advice, and you have no idea of their experience level, no idea of the equipment they have, and no idea of how it is installed, and no idea of the kinds of wood and other combustibles may be present (are they spraying volatiles without ventilation in the same enclosed space? (please do not try to argue that no one ever does)
I've seen too many people suffer lacerations, contusions, concussions, amputations and burns because the ignored simple, cheap safety precautions.

I could wear those magnetic bracelets to "improve my bloodflow and general health", because why not err on the side of caution, right? Because I carefully considered the possibility of what those things do for someone's physiology and determined them to be of no practical use. If I can prevent them from sticking to a ferrous object by placing 2-3 sheets of paper between the magnets and the object, how on Earth is any appreciable magnetic field going to get through a few layers of epidermis and affect my bloodlfow? It's called common sense based upon obvious facts at hand.

There is a known ratio of air/dust particles that causes an explosion... it was determined in a lab using scientific principles. The range of air/dust ratios that can cause an explosion are not in question. It's fact. To create such a ratio, the quantity of wood removed per second is also, therefore, a known quantity for a specified CFM of air. For even a 1 HP dust collector, the amount of dust created by a typical home machine comes nowhere near the minimum ratio. If memory serves, a sander would have to remove something insane like 1/4" depth of wood per second over a 12" x 12" board at 500 CFM to approach the proper ratio (these are not the actual values, I just remember them being something entirely insane that I knew could never be reached in nearly anything but a near-industrial setting). Those are the facts, and I based my decision upon them, not upon scare tactics. I'm not erring on the side of risk, I'm seeing zero risk possibilities, and therefore not doing any further mitigation. If you feel you reach that industrial level setting and need to do something about it, fine... but I can't see someone who install a 3-5HP DC creating that much dust, and if they were, they would be chasing down why their system is not removing dust fast enough and realize 3-5HP is not nearly enough.

[Alan Gan]

Seems there are different views on the safety from Dust Explosion.

Just my 2 cents but I believe humidity could also be factored in, correct? My take on Grounding the Flex tubing that I am using would be very simple and very efficient. I would just connect into the spiral wound steel that is already running throughout the entire length of the Run.

I could tap in at either end or as far as it goes anywhere along the Run by connecting a piece of copper wire and attaching the other end to a ground source. I think if I do it, I would tap right in at the separator and run the copper into the drum and connect to the drum, then I would connect another piece of wire to the exterior of the Drum and run that to a ground source (just sand to bare metal for good conductivity).

Why even fool around with running a separate piece of copper wire (when using this type of tubing)? Thoughts?

[phil harold]

I am with Dan on this one!

Let's not go down this road again... this has been discussed time and again.

[Art Mann]

There are those who believe the world behaves according to well understood principles of physics and chemistry. There are others who believe such information is only "book learning" and the "real" world operates in some other unpredictable way. It isn't really possible for a useful conversation to take place between the two groups of individuals.

[Greg Peterson]

There are those who believe the world behaves according to well understood principles of physics and chemistry. There are others who believe such information is only "book learning" and the "real" world operates in some other unpredictable way. It isn't really possible for a useful conversation to take place between the two groups of individuals.

Bingo.

I've noticed there are two things not brought up in this thread.

The purpose of the separator. This is not a matter of performance. To be clear, it simply reduces the frequency with which you need to clean the DC filter.

How much of that flex hose are you using? The pictures seem to show a lot of it in use. This would be more a concern to me than trying to implement a means of separating dust particles from chips.

I have the HF DC unit, with the Thein baffle and Wynn Environmental cartridge filter. The inlet on the DC is 5". I run an 8' length of 5" flex hose, reduced down to 4" at the machine. I do not attempt to run a DC network with this unit. I think it works fairly well in my shop, one machine at a time.

I often times use supplemental DC via my shop vac. On my TS, I use the shop vac on the blade guard. I also have a cross cut sled that encloses the cutting area and uses the shop vac on the top of this sled to help capture chips and dust from the top side of the cutting action. Between the DC and the shop vac on top, and the shrouds, virtually no dust escapes.

Sled with Guard.jpgIMG_0851.JPG

My Dylos particle counter indicates that despite my best efforts, there remain instances when my best DC practices are inadequate. Having had to fabricate DC solutions for all my power tools (drill press and jointer were the biggest offenders), any short comings in my efforts is due to the lack of capacity of the HF. I think I am getting about as close to the HF maximal capacity as is possible. Even at that, the idea of running a network, while certainly convenient, just seems to be a less than ideal application of this unit.

[Jim Neeley]

As mentioned above, sealing the separator is key.

A stick of incense is a great leak detector; if there's a leak it will be obvious as it draws the smoke in.

Jim in Alaska

[Michael W. Clark]

I have a small hobby shop and similar collector (do industrial DC in my day job). For me, it was better to leave the collector stationary and have the tools located near it. I currently have short runs of 4" S&D with minimal flex at each tool. A copper wire is wrapped around the outside of the pipe and attached to the machine at the hood end, then to the collector at the other end and finally a support pole in the basement.

My thought process is that I have similar length of run with the pipe so I have less overall losses by using it instead of the hose. I am planning to change it out to metal HVAC duct and upgrade the machine ports too. So much more flexibility with metal. I'll probably do a short copper jumper across any short flex pieces.

My tools are basically stationary or used roughly in same spot all the time.

Mike