Thread: Farewell, shop vac ... soon

Pictures? That way us novices can get ideas.

OK ...

Here is the pick-up point I use for the floor vacuum, the one usually connected to the drop saw.
IMAG0217.jpg

Here is the same flexy, disconnected from the saw and with a metal transition and either 3 or 6 M of 100 mm flexy attached.
IMAG0215.jpg

Here is the floor unit. I thermo-moulded a 90 mm PVC pipe to the black floor unit and fastened it with self tappers.
IMAG0216.jpg

Finally, here is a shortvideo showing how it devours everything that will fit into the floor unit.
Floor Vac Video - YouTube

Well ... bugger ...

Using the cyclone to extract dust from sanders etc does not work as well as I had hoped.

The Festool belt sander is hopeless. The internal fan is great, but the dust pickup is on top of the belt and much dust is thrown behind the belt. This also happens with the shop vac hooked up. Just a poor design so far as dust collection is concerned ... nothing new.

The shop vac works far better with my RO Sanders and with the drill press and the morticer. To be expected, I suppose. The cyclone works with most of these tools ... kind of. But if the ROS pad is partially off the edge of the job, I get dust blown around ... not so with the shop vac hooked up. My guess is that the shop vac is moving at least three times as much air as the cyclone when hooked up to hand tools.

And the Festool router is an unmitigated disaster. I bought the plastic dust extraction hood and tried it out. It might work to some reasonable extent in plunge mode, where the dust and chips can only move up, but in any other mode its almost a waste of time bothering with dust extraction.

The 100mm line and the floor sweep work, but once I choke the pipe diameter down for smaller tools I am in trouble.

If I am missing something, please tell me.

I don't think you are missing anything other than these machines are designed and work best with the vac due to airspeed needing to be better than volume. Routers are the same, airspeed trumps volume and always will in certain circumstances, especially high speed cutters where it is difficult to slow the debris and dust down enough for the volume flow of the cyclone to be effective. Use the vac, put it into a semi enclosed box and ventilate the enclosure with the cyclone.

Originally Posted by John Samuel

Well ... bugger ... Using the cyclone to extract dust from sanders etc does not work as well as I had hoped.

Chris has pretty well summed up why this happens - but read on

The Festool belt sander is hopeless. The internal fan is great, but the dust pickup is on top of the belt and much dust is thrown behind the belt. This also happens with the shop vac hooked up. Just a poor design so far as dust collection is concerned ... nothing new..

Using my DC works fine on my Makita belt sander, Festool and Ozito ROS but I use at least a 50 mm hose and for the BS a 100 mm hose. I have only compared air flows against a small shop vac - I can't bring myself to buy a larger shop vac but I might see if I can borrow one sometime.

The shop vac works far better with my RO Sanders and with the drill press and the morticer. To be expected, I suppose. The cyclone works with most of these tools ... kind of. But if the ROS pad is partially off the edge of the job, I get dust blown around ... not so with the shop vac hooked up. My guess is that the shop vac is moving at least three times as much air as the cyclone when hooked up to hand tools.

Your observation is purely to the visual dust which the sheer airspeed generated by a shop vac has a hope of catching. However what you don't see is the fine dust which needs volume not speed extraction. But you wont get volume extraction though small orifii. What you should do is place a 6" opening connected to your cyclone in the vicinity of your work since it will do a far better job of collecting the fine dust from the general area than the shop vac. Most people get hung up on chips but I don't worry about chips - a good example of that is using a lathe. I use a DC with a bell mouth hood on my lathe but when roughing things down the big chips fly all over the place but the fine dust levels where I'm standing are the same as shed background so I know I'm not breathing in fine sawdust. When I finish roughing I vacuum up the chips with the DC and leave the DC running for 10 minutes - at all times the dust stays at shed background levels.

And the Festool router is an unmitigated disaster. I bought the plastic dust extraction hood and tried it out. It might work to some reasonable extent in plunge mode, where the dust and chips can only move up, but in any other mode its almost a waste of time bothering with dust extraction.

Freehand routers are very awkward as they will spray stuff around over a wide area. My tests have shown that even using a shop vac that using a router free hand router exceed the OHS dust levels by more than 20 times in less than 2 minutes. If you want dust control with a router I suggest reorganizing your work to use a router table and enclosing the router from underneath and venting that and the back of the fence with a DC. I haven't tested a router table as I am still in the middle of dust extraction set up for it.

The 100mm line and the floor sweep work, but once I choke the pipe diameter down for smaller tools I am in trouble.

What size hose are you using? If you use anything less than 50mm you will definitely have problems. AT 50 mm a big shop vac should be able to draw more air through it than any DC, at less than this the Shop vac will be even more successful.

I've been using a 100 mm flexy on my Makita belt sander for years I have 2 or 3 occky strap loops to the celing to take the flexy weight - it works great

This graph shows the difference between DCs and VCs

The shaded area show the region where DCs operate, VCs operation on the the far right of the graph 50-90" of pressure, but the small motor/impellers cannot move more than about 100 CFM so that is their upper limit.

This graph shows the 4" duct on a DC can move at most about 400 CFM, while for a 2" duct it should be about 70 cfm but for some reason when I measure it I get 120 CFM. Whatever it is, for 1.5" or 1" you can see that DCs will move bugger all air. VC's on the other hand thru a 1.5" hose can move about 70 cfm at 50" and just over 100 cfm at 90" Adding a bigger hose to a VC makes no difference to their CFM as the motor/impeller is already maxed out at 100 cfm.

Bob and Chris,

Thanks for the feedback. Because the orifii are so small, I doubt the size of the duct from the cyclone makes a lot of difference. Was using a 100 mm hose, which dropped down to a 50 mm hose which dropped down to 32 mm for a few inches before hooking up to the machines.

BELT SANDER. I think the Festool bet sander is a lost cause. The internal fan is a beaut, but even with the shop vac hooked up dust is left behind the belt of the workpiece. The machine picks up dust on the top of the returning belt, but a lot of dust does not make it there. The dust collection orifice is only 23 X 10 mm. The internal fan sure pushes out a bunch of air, which helps, but with an orifice this small the size of the hose from the cyclone is immaterial. A 100 mm line still chokes down to a 23 X 10 mm orifice. I think the only solution is to use the shop vac and then to scavenge dust with the cyclone ... unless you guys have any other bright ideas. I was thinking of making up a shroud (fastened to the rear of the sander) that allowed me to use a 100 mm line running up to the base of the machine and to connect a short piece of 32 mm line from the small dust port to that. If I can make that work I might have excellent dust collection. More thinking time required ...

Here is a pic of the dust left behind the sander after a short sanding session on a piece of scrap ply. This is terrible engineering ... woeful ... even I could design a better dust pick-up for this sander.
IMAG0218.jpg

RO SANDERS. I have two Festool sanders; round and triangular. Both have 22 mm orifices. With the shop vac hooked up, it is sometimes difficult to overcome the suction to move the sander across the workpiece, so I may cut some channels from the holes to the outside edge. These tools need the shop vac. The cyclone does not move enough air through that small orifice. Again, with an orifice this small, the size of the hose from the cyclone seems immaterial.

BISCUIT CUTTER. The orifice on this is only 16 mm, but the shop vac leaves no visible dust behind. Even the cyclone works pretty well in terms of visible dust, but I'll continue to use the shop vac to move more air faster and grab more of the fine material.

ROUTER. Another lost cause. I use a spindle moulder for the most part and dust collection there is good; but sometimes a portable machine is needed, for instance, to rout a rebate in the back of a cabinet. In this circumstance dust collection is so bad it is not worth hooking up the vac. I think the best option here is to put the job on my spray table (which is on wheels), and drag it outside for router work ... bugger!

Back to Plan A, which was to enclose the top half of the vac and to duct this to the cyclone. That way I can still pull the bottom off to empty the canister and clean the filters without worrying about the enclosure. I'll do a bit of thinking first ... see if any other brainwaves toss up alternate solutions because it annoys me to be running both the shop vac and the cyclone when using hand tools.

John, I assume that you are not using a Festool vac as these are speed adjustable to allow for the tool sticking to the work.

Chris,

You assume correctly. It is a reasonably powerful wall mounted Hoover garage vac (with a funny looking cyclone). Cannot bring myself to part with half the cost of a 4HP Clear Vue cyclone for a vac ... a very nice vac, but still a vac.

That router is a horror. The shop vac is powerful, but the chips are coming off the cutter so fast that they spray out of the bottom. I reckon the dust extraction might work pretty well in plunge mode, but I have never done that.

The orifii sizes may have less significance than the usual interpretations because the internal fans in these tools also "push" air out of themselves. So it's a matter of making sure that you at least match the air being pushed with sufficient pull (volume flow) by the DC. If all your cyclone suck is being directed to the power tool the clearvue could simply be cavitating and not sucking much air - did you at least try to open another duct in the same line at the same time as you use the power tool?

It's a pity you are not a bit closer or Id offer to come over check you setups for flow rates and fine dust.

Bob,

Yes, I did try opening another duct ... couldn't see any real difference, but that does not prove it was not there.

The internal fans do help. The internal fan on the BS is a beaut ... pity it is in the wrong place.

Perth is a long way away ... but feel free to drop in for a cuppa or a beer any time the urge takes you ... and bring your instruments.

Building a cabinet for my old contractor saw. Will take pics once finished.

The air flow meter and particle counter fit in a small briefcase but bring the test pipes would be a bit tricky. We could make up from some leftover 6" and 4" duct but I'd need a 9" piece to test the cyclone. Well you never know!