Thread: Dust extraction cupboard - ideas?

Originally Posted by Dave32

Hi all,
I recently purchased a new 12" table saw and finally ditched the old Triton workbench which had been in use for about 15 years. I always used the Triton out on the patio or the lawn so dust was not so much of an issue. The new table saw is set up in a double garage and due to its weight, obviously has to remain there. Being fairly inexperienced with this equipment, I very quickly discovered the huge problem of dust that is created, particularly from MDF. I have worn a dust respirator mask, but I found the dust got into everything - in my hair, my clothes, and absolutely everywhere in the garage.

This is what you can see - with MDF its the stuff you can't see that is more of a problem.

I have not bought my DE unit yet but plan to get one of the commonly available 2HP 2 bag systems. That's about the largest I can run (power wise) as well as fit into the garage.

1. I was planning on using two fixed 4" PVC plumbing pipes to vent it to the back of the garage to extract any dust smaller than 4 microns. Would I need to include a fan to help this or would the DE unit provide enough oomph to discharge this dust itself? I'd rather try and discharge it than have a cupboard build up a large quantity of fine dust.

Why muck about with two x 4" hoses - this is still very restrictive and will limit flow to 800 cfm for the entire system.
BTW airflow through 1 x 6" flex is = 3 x 4" flex.
Better still (since the system on that side is under pressure) why not get some large diam (eg 9" or 12") foil covered aircon ducting. This will have such a low resistance that you will not constrict the flow.

2. Should this vent be at the top of the cupboard or on the side, or doesn't it matter?

It doesn't matter

3. I'm concerned about the motor overheating as it will be enclosed with no air intake from outside the cupboard. Would it be okay or would I need to build some type of air intake port around the motor? Perhaps a short length of 4" pipe going between the cabinet wall and the motor? I'm also concerned about dust escaping from here too. Would the motor provide enough negative pressure?

Hang on you are going to be pushing at least 400 cfm through the box which is more than enough to remove the motor heat. The one place you may run into difficulty is hooking up to a power tool. Then you might be down to 10's of cfm which will overheat the motor - one way around this is to leave another port open to generate enough air flow.

3. How easy is it to remotely switch the power of these units? Once mounted inside the box the switch becomes out of reach.

Dead easy - you just need some multi strand cable of the right gauge that will handle the connections

4. What about noise? Could I use a rubber mat to sit the DE unit on to reduce any noise or am I wasting my time here? How noisy are they?

That didn't seem to do much for my system but you will really need to insulate the walls of the cupboard. - have you seen my thread on how I insulated my dust extractor?

Hi Dave,

As usual, Bob has not left much for the rest of us to answer as far as dust collection goes.

I just wanted to congratulate you on looking at available power supply in your planning. Many do not and buy a big dusty then struggle to find a way to run it when the circuit breakers start popping. Just be careful to check whether any circuits you are using in the workshop are also shared with any power points in the house. Not many garages are wired up with sufficient capacity to run what most woodies want to run. Upgrades can be costly.

Doug

Originally Posted by doug3030

. . . . I just wanted to congratulate you on looking at available power supply in your planning.

Good point.

RE: OP
Exactly where outside do you intend venting to?

Thanks Bob and Doug for your thoughts.

I had the idea of running 2x 4" vents from another post I read here on the forum but I guess it makes sense to increase the vent size if the intake is 2x 4" as well. The aircon ducting sounds a great idea and I'll investigate getting some of that.

The double garage is about 15 metres from the house and has a dedicated 30 amp circuit to it. I would have liked to have built Bill Penn's cyclone dusty but I would not have the power available to run a 4HP motor, and although I couldn't find info on the current required for a 3HP motor I would think it would possibly come too close to the limit. I'm on a rural property here and also have a 1kW water pump in the garage that supplies the house so I have to consider that too. Space is somewhat of an issue too so the best option looks like one of the 2HP units.

The proposed vent will be at the back of the garage and will be well away from the house with only sheep paddocks out there so the dust shouldn't be a problem. I did take a look at your thread on insulating your dust extractor Bob and you've done a great job. I'll get the DE first and see just how noisy it is before deciding on insulation.

Dave

Originally Posted by Dave32

Thanks Bob and Doug for your thoughts.

I had the idea of running 2x 4" vents from another post I read here on the forum but I guess it makes sense to increase the vent size if the intake is 2x 4" as well. The aircon ducting sounds a great idea and I'll investigate getting some of that.

The double garage is about 15 metres from the house and has a dedicated 30 amp circuit to it. I would have liked to have built Bill Penn's cyclone dusty but I would not have the power available to run a 4HP motor, and although I couldn't find info on the current required for a 3HP motor I would think it would possibly come too close to the limit.

The HP ratings on electric motors are nominal. The current and hence the power developed varies quite a bit. On start up the current might be 30 - 40 A for a second or so (don't worry the breakers are designed to handle this) then when it settles down it might only draw 7A (at 240V that's ~2 HP), under a light load it might draw 9A (2.6 HP) under a medium load it might be 11A (3.2HP) and under a heavy load it might be 13A (3.8 HP). A 30 A line should be able to handle 2 x 15A lines plus some lighting so you could use a 3HP DC and a 3HP TS.

My nominally rated 3HP DC draws 9.2 A when its running (at local 240V, thats 2.93HP)

The proposed vent will be at the back of the garage and will be well away from the house with only sheep paddocks out there so the dust shouldn't be a problem.

Sounds fine - as long as the vent is as far as possible from any shed opening otherwise the dust will head straight back into the shed.

Dave,

BobL knows his stuff. It sounds like good advice. I am easily running a 4HP cyclone from a dedicated 15 Amp circuit. Until summer, it ran on a 10 Amp circuit. The remainder of my shed is all 10 Amp outlets (on I think a 20 Amp circuit). I have no problems running any of my machines (my biggest woodworking machine motors are 1.5 HP, but your 12 inch saw will have a bigger motor) as well as all the lights and still have no problems when the compressor kicks in unexpectedly.

As Bob indicated, if you have a 30 Amp circuit you should have no problems with a 3 HP dusty as well as the machine it is servicing. Depending on the HP of your larger machines (table saw, compressor, linisher etc), you may very well be able to run a 4 HP cyclone. According to the readout on the keypad, my (nominally rated) 4HP cyclone motor draws about 9 Amp on start up (the VFD gives it a soft start) and only about 7 Amps when it is running with one blast gate open.

I am no electrician, but it would surprise me if you were not in pretty good shape so far as power is concerned. Because I am no sparky I got an electrician to do a survey of my shop to ensure I had enough power, and told him I needed to run the cyclone and the table saw and have the compressor start up while I was using these machines. He was happy with the arrangement I now have, and I have had no problems. Having a sparky do that survey gave me a lot of peace of mind.

Hi Dave,

I do not say ignore Bob and John. They may well be right, but don't forget the John is hedging his bets by saying that a qualified electrician approved his setup. I say also seek professional advice, because every setup is different.

From what you say it may well be possible to run a 3hp dusty, and an electrician may well approve it, BUT it might not run all that well.

I will concede that your 30 amp circuit may well be capable of handling more load than that, and that once your machines are running that the higher start-up energy requirements are met, the circuit may possibly be pulling less than 30 amps. However, teh lead from the house to the shed may be rated at 30 amps, but what is the rating of the wires from that point on? what is the power rating of the circuit breaker? How many 15 amp power points are in the shed? You will need at least one to run a 3hp machine, such as a 3hp dusty. What is the rating of the circuit that you intend to plug in the dusty to and what is the rating of your 12" table-saw? even if it is 10 amps the 10 plus 15 is 25 amps and the lights will account for the other 5 amps easily.

I can manage the power in my shed to run that much and more, but I will cite the example of the circuit that runs through our kitchen.

If our oven thermostat kicks in or another appliance such as an electric frypan or a deep fryer is put into use, the exhaust fan in the range hood comes to a virtual stop. You can clearly hear a drop in speed and performance to the stage that the kitchen fills up with smoke.

The same scenario in your garage/workshop is going to result in a significant drop in dust collection capability as the speed of your impeller drops when you start up the tablesaw, bandsaw, sander or any other machine which requires maximum dust collection effort.

In am not saying that it will not work but at least give it some thought before you go above 2hp for your dusty.

Doug

Originally Posted by doug3030

Hi Dave,

I do not say ignore Bob and John. They may well be right, but don't forget the John is hedging his bets by saying that a qualified electrician approved his setup. I say also seek professional advice, because every setup is different ...

... In am not saying that it will not work but at least give it some thought before you go above 2hp for your dusty.

Doug

Doug is, of course, quite correct.

Actually, I would say that unless you are a sparky, or at least have years of experience with such issues, that not getting a survey done by an electrician is a mistake. In a like manner those of us who are not doctors should probably not try to diagnose or treat potentially serious illness in ourselves; those of us who are not lawyers are not advised to defend ourselves in court.

I'd be surprised if Dave could not run a 3 HP dusty with his saw, but nevertheless, were it my shop, I agree with Doug. I'd get a sparky to do the survey, if only for the peace of mind. I went one step further and found a sparky who had years of experience wiring up all sorts of motors in maintenance workshops. He reckoned I might be borderline ... might be OK with nothing more than my original 10 Amp outlets, so we made no changes when he wired up my cyclone motor and VFD to a 10 Amp outlet.

All went well for about 3 months, until summer kicked in. A slight drop in current to the house caused by thousands of air-conditioners running as well as a hot ceiling space that dropped the current the cables in the ceiling could carry occasionally caused the VFD to cut off the cyclone motor when I started a large woodworking machine. Bugger!

So, I had the dedicated 15 Amp circuit installed to the cyclone, and the cabling to the 10 Amp outlets in the shed upgraded (all up cost of about $630.00). No more problems, but in this case we knew from the outset that upgrading my power was not going to be difficult or expensive, if it became necessary.

Originally Posted by doug3030

Hi Dave,
I do not say ignore Bob and John. They may well be right, but don't forget the John is hedging his bets by saying that a qualified electrician approved his setup. I say also seek professional advice, because every setup is different.

I know a fair bit about electrical stuff having worked on up to 8kV stuff at work and having to tell the sparkys that used to come and wire our labs up how to install motors and fans etc, but like others I would also preface any of my my remarks by saying one should get a final approval from a qualified electrician.

From what you say it may well be possible to run a 3hp dusty, and an electrician may well approve it, BUT it might not run all that well.
I will concede that your 30 amp circuit may well be capable of handling more load than that, and that once your machines are running that the higher start-up energy requirements are met, the circuit may possibly be pulling less than 30 amps. However, teh lead from the house to the shed may be rated at 30 amps, but what is the rating of the wires from that point on? what is the power rating of the circuit breaker? How many 15 amp power points are in the shed? You will need at least one to run a 3hp machine, such as a 3hp dusty. What is the rating of the circuit that you intend to plug in the dusty to and what is the rating of your 12" table-saw? even if it is 10 amps the 10 plus 15 is 25 amps and the lights will account for the other 5 amps easily

If the 30A line is independent of the house appliances, a 3HP DC and a 3HP TS will run fine in your shed.
A 3 HP DC will be fully loaded less than 10 A- the reason they put them on 15A lines is usually because of the starting currents.
A 3HP TS will be free running about 7A and only go over 10A while you are actually cutting, however most breakers are designed to cope with small periods of over current load.
5A of lighting is ~1.2 kw of lighting (that's ~12., 100W old-school incandescent lamps or 30 od fluoro tubes)- I doubt you have that.
However, if the devices say requires 15A line/plug then you should get 15A sockets and lines installed.

If our oven thermostat kicks in or another appliance such as an electric frypan or a deep fryer is put into use, the exhaust fan in the range hood comes to a virtual stop. You can clearly hear a drop in speed and performance to the stage that the kitchen fills up with smoke.

In the case of the oven this is clearly incorrect wiring as electric ovens should be located on a separate circuit.

Originally Posted by BobL

In the case of the oven this is clearly incorrect wiring as electric ovens should be located on a separate circuit.

I believe you are correct there Bob. But the previous owner of this house was an electrician, as they say mechanics have the worst cars...etc

There are plenty of examples of corners being cut with electrical installation around this house, usually just not finished off nicely, nothing unsafe. The biggest bonus from having an electrician's old house is the power sub-board in the garage with a 15 amp and a 10 amp circuits. He had a 15 amp welder.

Doug

Originally Posted by BobL

If our oven thermostat kicks in or another appliance such as an electric frypan or a deep fryer is put into use, the exhaust fan in the range hood comes to a virtual stop. You can clearly hear a drop in speed and performance to the stage that the kitchen fills up with smoke.

In the case of the oven this is clearly incorrect wiring as electric ovens should be located on a separate circuit.

I'd go so far as to say that the wiring is faulty as well as incorrect.

If the fan is dropping speed to that extent, but you are not drawing enough current to trip the breaker, that there is voltage drop in the wiring, which will either be as a result of a bad connection or possibly because the wire isn't specced high enough.

In either case, voltage drop equates to heat being produced, and I would get that circuit checked as soon as possible, because you don't need it starting a fire.

It's possible that I may have the capacity for running a larger HP dusty, but I think the largest problem I face at the moment would be space in the garage for setting up a larger DC. I don't have a huge amount of woodworking gear, and right now it's just the table saw, small drill press, compound saw and a small Ryobi bandsaw. After you fit in the workbench, two walls full of shelving and then gardening gear including a large ride-on mower and a mulcher there's not a lot of space left in there. Add to this a pile of scrap timber I've collected over time and I'm having trouble fitting in the 2 bag dusty as it is... so I think I'm going to have to stick with the 2HP unit (for the time being anyway).

I'm working on improving the space usage with overhead storage racks planned later on as well as moving the mower but that's another story...

Bob mentioned lighting earlier... At the moment there is no lighting and it is a daytime only hobby but I recently picked up a dozen second-hand double fluoros to put in there, although I probably won't use all of them. The power board has a maximum capacity of 3 circuit breakers. At the moment one is allocated for lights, one 15A circuit for the 1kW water pump and anything else I want to run (radios, drills, sander etc), and the third being on a 20A circuit just for the saw.

Do you think it would be possible to run the 2HP dust collector on the same 20A circuit as the saw? The manual for the saw says it is a 2.2kW 3HP motor.

Dave

A significant benefit of a 4 HP Clear Vue cyclone is its very small footprint. At $2,250 it is more expensive than a 2 or 3 HP dusty, but it is more powerful and it vents outside ... no bags to clean and no invisible dust returns to the shop once it is in the system. The cyclone is circled in red in the pic, because it almost disappears in the clutter.
170A.jpg

I'll leave any detailed comment on power circuits to those better qualified to answer them.

Hi John
The Clear Vue cyclone is by far the best choice for maintaining clean air in the workshop and I would just love one of those, but I'm going to have to put that on my wish list at this time. I think that is the same design as Bill Penn's cyclone that I had thought about building. According to Bill's site I believe they are pretty noisy in operation too!

I had a quick look at 4HP motors to see what they cost here a few weeks ago but wasn't sure if you can get them in single phase or not. Anyway that's going to have to be a project further down the track and I'm going to have to make a compromise at the moment with a 2HP dusty looking like the potential purchase. I'm rather anxious to get the table saw back into operation!

Another question for the knowledgeable people out there... now as I haven't bought one of these 2 bag dust collectors yet I am not exactly sure how these operate. Obviously you have the motor driving the impeller which then drives the sawdust up the flexible tube towards the 2 bags. When it gets there I'm wondering how it separates the sawdust and the air?
Basically I am wondering if it is possible to do away with the air filtration bag at the top, and put some form of (plastic?) cylinder in place with a vent that directs the fine stuff straight outside? Rather than sit the dusty in an enclosed cupboard with a vent, can I vent the DC directly? Or does it need to have the bag on top to complete the process of separation? These are probably questions already asked elsewhere and I did have a look but couldn't see anything. It wouldn't be a problem if some of the sawdust was pushed out the vent as well, as long as the majority stayed in the lower bag. This would avoid the problem of continual fine dust build up inside the enclosed cupboard (as well as the need to construct a cupboard). I assume it's not possible... or is it?