Thread: Wall mounted dust collector vs small dust extractor

Originally Posted by BobL

... Comparisons with vacuum cleaners are not that useful.
...

Agreed, Bob, but I have obviously not made the point that I was trying to make. Another go:

The 1 HP vacuums that Jekkil is considering will not collect the fine, dangerous dust and will do quite a poor job at collecting the visible dust. The OP will be disappointed and will have highly visible sawdust on floor, benches and elsewhere in his workshop. His options will then be to sweep it up manually or to get a portable vacuum. In my view, the 1 HP ducted vacuum is doomed to failure.

Jekkil seems committed to wearing a mask and minimising risks, but he will still want to remove visible sawdust from his shop. Will he sweep or get a portable shopvac?

My suggestion is that, for him, the most bang for the buck will be from a good shop vac with a cyclone.

He does not have the space or the available $$$'s to tackle the dangerous invisible dust. He knows this and has repeatedly referenced masking up.

Originally Posted by BobL

Neither of those DCs will cope with even the visible sawdust dust from a table saw or thicknesser, let alone the invisible dust.
Remember for a TS you need 2 collection points cabinet and OH guard.
Even a stock 2HP DC will struggle and they need to be modified to grab more fine dust - See sticky at top of the dust forum on how to do this.

Can you locate the DC outside and duct back into your shed?

If you do end up with either of the two in your OP then you will need some forced ventilation to cope with the fine dust.

Hey Bob, I'm resuming this topic as I convinced myself to buy a 2hp dust extractor from carbatec. However, I now have a doubt.
I'll be using it essentially with a router table, a thicknesser and a table saw.
The table saw has a 63mm port. Won't the airflow be dramatically reduced if I pass from a 100mm flex to the 63mm port? Isn't there the risk to starve the impeller?

Originally Posted by Jekkil

Hey Bob, I'm resuming this topic as I convinced myself to buy a 2hp dust extractor from carbatec. However, I now have a doubt.
I'll be using it essentially with a router table, a thicknesser and a table saw.
The table saw has a 63mm port. Won't the airflow be dramatically reduced if I pass from a 100mm flex to the 63mm port? Isn't there the risk to starve the impeller?

Correct.
A stock 2HP is a substandard performer b ut can be improved substantially - see the sticky at the tope of the dust forum on modifying the 2HP to fully utilise 150 mm ducting.


You have a couple of options.

Best option is to open up the port in the TS. If the port is part of a blade shroud then form an enclosure under cabinet and fit it with a 150 mm floor drain flange.
Dont forget you will need OH dust extraction from the blade guard as well

Second would be to locate a 150mm bellmouth hood above the TS - could even be a prt of the blade guard. to scavenge fine "floaty" but up from round the saw.

Plenty of examples in the dust forum of how to do these.

Thanks Bob!
These make sense and are pretty clear. However, I won't be able to make any of them at the moment.
What would be better between:
1. Using the 2hp DC as it is, connected to the 63mm port and the smaller port on the blade guard
2. Using the 1hp DC in the same way
3. Using a different solution...but which one?

Just keep in mind that I'm working in a single car garage (6.5x3.5m) and this is just a weekend hobby - therefore I prefer to spend my time making things more than improving tools.

Thanks again!!

Originally Posted by Jekkil

Thanks Bob!
These make sense and are pretty clear. ...

As they used to say at Bathurst - "No substitute for cubic inches".

A 63 mm port only has 17.6% of the sectional area of a 150 mm port. It is a constipation point!

Duct Diameters.jpgComparison of Duct Sectional Areas.

so, basically what will happen if I connect a 100mm hose from a 2hp dust extractor to my table saw (63mm port + blade guard port which I believe is 35mm)?
Isn't the dust extractor going to pull just the right amount of air needed to collect sawdust? (sorry...I'm a bit confused )

Jekkil. I think what you have is a job site saw that are light and portable. They were never meant for hobby use but because of the small size and being inexpensive have been enthusiactically adopted by people like yourself. On a construction site they are not often used in a fully enclosed room so the dust collection needs are minimal and focused on getting the visible dust and complying loosely with regulations. To that end they are made to use a shop vac since most construction sites would not have a HVLP collector because of size, portability and power requirements. So unless you are willing and able to modify the base for 4"/100mm duct and replacing the overhead with the same you are better off using a shop vac with the table saw at least until you are in a position to get a better saw that has the bigger ports. Getting the 2hp DC and using the 6"/150mm bellmouth above the blade as Bob mentioned, in addition to the shop vac will get the floaters coming off the top of the saw that the little hose won't. I understand turning both on and off will be a royal pain in the where you have been but it will be the best for now. The DC will work better on your other machines and the ones you get down the road.

Pete

Thanks Pete! Yes, correct, my saw is a portable saw. I agree with what you said about using a shopvac. However, sawstop recommends a shopvac capable of moving at least 170CFM and so far I couldn't find one with this performance. At least at a reasonable price.

Ok...another thought. I understand I cannot hook a 100mm port to a 63mm port. Fair enough.
What if I split the 100mm port into 3? One 63mm port connected to the base of the saw, one 32mm port connected to the guard and a 70-75mm port left open? Will I have the right flow of air since I'm not restricting anything? Or am I being delirious?

You haven't factored in the 4" hose from the dust collector will only have a few inches suction compared to the 60"+ that a shop vac has. HVLP (High Volume Low Pressure) verses HPLV (High Pressure Low Volume. The DCs low pressure won't draw much through the small ports where the shop vac can overcome the resistance in the small hoses. SawStop is unrealistic thinking there are Shop vacs moving 170CFM. My cheap 6hp is claimed to be 135CFM and a Mirka is 160CFM. Don't get me wrong, I have a SawStop ICS and they are great machines but they should be more clear about what they want. DC or a Shop Vac? If it is going to be a shop vac then they should specify which ones.

Pete

eeez...confusion is definitely growing!
I think I will simply keep covering my garage in dust...

Originally Posted by Jekkil

eeez...confusion is definitely growing!
...

You are not the first to say that!

The problem is exacerbated by manufacturers and salesmen who peddle a lot of BS - most published performance figures are "exagerated". Most commercial dust systems underperform. If you want to do more research, the best accessible sources that I know are BobL on this Forum and (American) Bill Pentz:
Home Page, Bill's

All right...I'm almost there with my decision. Hopefully it will come before I decide to give up on woodworking

I found a 2HP unit with the pleated filter and I'm really considering it. At least I will save some money in case I find that it is not what I need.

The last questions:
1. It is the old carbatec FM300. The white one with the rigid squared duct between the motor and the ring (similar to this: OLTRE Dust Extractor 1ph 2hp | Woodwork Machinery..). Does it make any difference in terms of performance? Can it be considered as one of the improvements in Bob's sticky thread?
2. What should I be looking for when buying a used unit?
3. Are we really sure that this unit (with the modifications suggested in Bob's sticky thread) is going to be better than something like a Camvac?

Originally Posted by Jekkil

All right...I'm almost there with my decision. Hopefully it will come before I decide to give up on woodworking

I found a 2HP unit with the pleated filter and I'm really considering it. At least I will save some money in case I find that it is not what I need.

The last questions:
1. It is the old carbatec FM300. The white one with the rigid squared duct between the motor and the ring (similar to this: OLTRE Dust Extractor 1ph 2hp | Woodwork Machinery..). Does it make any difference in terms of performance? Can it be considered as one of the improvements in Bob's sticky thread?
2. What should I be looking for when buying a used unit?
3. Are we really sure that this unit (with the modifications suggested in Bob's sticky thread) is going to be better than something like a Camvac?

I actually think a camvac would perform better. The 2hp is likely to only pull 100cfm through the 65mm port. Going by the manufactures specs the 2 motor is 240cfm and 3 motor is 340cfm. With the high static pressure of these units that number wont go down much. Keep in mid the 3 motor unit is 4hp.

Originally Posted by Davidmr

I actually think a camvac would perform better. The 2hp is likely to only pull 100cfm through the 65mm port. Going by the manufactures specs the 2 motor is 240cfm and 3 motor is 340cfm. With the high static pressure of these units that number wont go down much. Keep in mid the 3 motor unit is 4hp.

Yeah, exactly! I'm not sure I will be able to run the 4hp unit together with other tools.
Without considering the difference in price...I found the 3-motor unit here in Australia for a bit more than $1000.