Thread: Mens Shed Dust Collection

One of the dustiest machines in the Mens shed is the 600 mm twin drum sander.

There are 3 issues that stand out as to why dust cannot be adequately extracted from this machine.

The first one is the 2 x 100 mm ducts each have a wire grille which were easily removed with a pair of pliers.
The second is that 2 x 100 mm ducting still does not provide enough air flow (<800 CFM ) although I don't plan to address that just yet because it's pointless increasing the number or size of the extraction ports on that machine unless enough air can get into the machine to drag the dust away.

It's not so much of a problem if the workpiece cross section being sanded permits a decent gap between the feed belt and drums but mostly the drum sander is used for thin wide objects like chessboards and cutting boards so the gap is quite narrow.

DSoriginal.jpg

Our solution is to replace the front panel immediately above the workpiece with a stiff mesh like this

IMG_1916.jpg

The 3 x 20 mm SS strap has T-pieces TIG welded on the ends and the stiff galv mesh is held onto the strap by machine screws and washers.

We also plan to do the same to the similar panel on the back of the sander
IMG_1917.jpg

Eventually the entire top and the 2 x 100 mm ports will be replaced with a top incorporating a tapered 150 mm BMH.

More progress on the Mens shed system,

There are 2 bandsaws, a 14" 3/4HP and a 16" 1HP 3Phase unit.
They are located in the same area and are on wheels so can be moved out into an alley way to ease usage.

These Bss are rarely used at the same time so share a single 6" duct and only 2 x 100 mm ports go to each machine while we decide to add a 3rd one or not.

Blast gates will need to be added to the Y junction direct the suck to an individual machine but we just want to get as many machines connected as possible
BothBSs.jpg

The 14" unit has its under table collection located at the front of the cabinet.
It won't be quite as effective as having the extraction from the side but the there is no hinge on the lower cabinet door and the whole lower door comes away when the two lower tap like handles are undone.
The rightmost tap handle gets in the way of mounting a BMH on the side and VV.

The other port is attached to the cabinet door as shown
IMG_1926.jpg

Her is the other side of the 14" under table extraction
14inchside.jpg

The 16" BS is setup like mine at how with both ports attached to the cabinet door and the swing aside and stay on the door when the cabinet door needs to be opened.

16inchfront.jpg

Even with both connected to the same 6" duct they seem to work reasonably well.

Today I fitted the next 4 blast gates to the system and apart from connecting a 6" jointer and a 10" TS up to the system, all the machines in the main workshop are are now connected.
Not are all in their ideal collection state but at least they are connected.

We have finally filled our first 200L wheelie bin full of dust and I was surprised that it was not that heavy. I could pick it up with not that much effort so it cannot have been more than about 50kg.

The next phase is to do a Sydney Harbour bridge exercise and go around to every machine and optimise each machine's collection setup.
The worts machine is the new TS is just woeful with its single 4" port that gets clogged every few days with slivers of wood that get down the gaps in the throat plate.
The thing is still under warranty so I am reluctant to take to it with the angle grinder.

The stage after that will be to extend the ducting into the room where we store the 4 lathes.
They get very little use at the moment because . Maybe one lathe gets used once a week for a couple of hours.

By then the expansion plans for the shed may be advanced enough that we have to start all over again!

Getting towards the end of the ducting with the installation of a relief valve on the end of the 9" trunk.

This has been included in case all the gate valves are closed.
This means no air flow though the system including the enclosure which could overheat the impeller motor.

If all the gate valves are closed the hinged 6" hatch in the middle of the relief valve starts to be sucked open allowing some air in.
The cantilevered SS arm has a couple of 250g lead weights on the end of it to hold the hatch closed, unless all gates are close.
It still partially swings open with one gate open and is almost closed when two gates are opened.
I will add some more weights to see how it goes.

I was worried that it might whistle but it's only barely audible above general shed noise whether its fully or partially opened.
IMG_1947p.jpg

While I was up there installing the relief valve I too oa general photo so you could seed how its looking.
8 of the 12 Bgates are installed but not all the cords are installed.
Shed is definitely getting cleaner than it has been.

IMG_1949p.jpg

Originally Posted by BobL

Getting towards the end of the ducting with the installation of a relief valve on the end of the 9" trunk.

This has been included in case all the gate valves are closed.
This means no air flow though the system including the enclosure which could overheat the impeller motor.

Huh?? No air = minimal load and the VFD controls the rpm. It never seems to worry mine.

Originally Posted by Chris Parks

Huh?? No air = minimal load and the VFD controls the rpm. It never seems to worry mine.

No VFD on this one. Also theres a 7.5HP compressor in the same enclosure.

Originally Posted by BobL

No VFD on this one. Also theres a 7.5HP compressor in the same enclosure.

You are running it at 2850? If it is going to overheat it is with all gates open not closed.

Originally Posted by Chris Parks

You are running it at 2850? If it is going to overheat it is with all gates open not closed.

A motor running at full speed still needs air to be cooled irrespective of what load it has on at - even at minimal load if the fan is disconnected and it's inside an insulated box the motor will eventually overheat.

The shed has a fair size evap air con unit on it so at full DC motor load (3kW) there must be close to 2000 CFM of air-conditioned air from the shed t going through the DC enclosure that the motor can push past itself with its fan.

I've tested a few 3P 3kW motors and at full speed and zero load (i.e. nothing attached to the shaft) they still draw around 500W which needs to be removed in some way.
An impeller on a motor running at full speed might have no air moving through it but the frictional forces are still high. FWIW my 3HP DC motor still draws around 1000W with the inlet blocked.

If the DC motor is left running without any air going through the insulated enclosure all afternoon on a hot day when the enclosure reaches 60+ºC that DC motor will eventually have a problem.

You might find it hard to believe a men's shed would turn on but not use a DC for a whole afternoon but that's how they are.
If only a couple of blokes come in for a session and someone turns on the DC for a short job and leaves the DC on but closes all the gates, supervisor gets distracted, then we have a problem.
They might even leave it running all night with the gates closed.

What I'm really guarding against is if someone also decides to run the 7.5 HP compressor in the enclosure (e.g. spray paint).
Then instead of just 500W to deal with the enclosure has 5+kW of heat to deal now the DC, and compressor motors and pump, will definitely not be able to cool themselves.
Even if the DC motor had a VFD the compressor would still not like it

There are many solutions to the problem such as, automatic gates, or additional forced air cooling for the enclosure.
There's now a plan to expand the shed which looks like moving the enclosure so I am reluctant to do anything else to the enclosure until that gets sorted and was just looking for a simple solution to our problem.
All the materials were already in the shed and one of the TIG welding members was looking for something to do.

Why run it at 2850, the whole ethos of using a VFD was to get the impeller speed back to what it was designed to run at. As for overheating, if it is a concern then the design for the enclosure lacks allowance for the heat load being encountered.

Corrimal Men's Shed has a compressor in the same enclosure which is only just big enough for the cyclone and the compressor and the compressor runs a lot of the time supplying air for the blast gate control system. There has never been an issue with heat soak and build up with their system.

Originally Posted by Chris Parks

Why run it at 2850, the whole ethos of using a VFD was to get the impeller speed back to what it was designed to run at.

I agree its not ideal but that's all that was left in the budget so I recommended to the committee we get the Clearvue without the VFD and fit it later.
This may or may not happen as I am no longer a committee member or supervisor and only attend the shed on an irregular basis to attend to finish attaching machines to the ducting

Corrimal Men's Shed has a compressor in the same enclosure which is only just big enough for the cyclone and the compressor and the compressor runs a lot of the time supplying air for the blast gate control system. There has never been an issue with heat soak and build up with their system.

There's a few differences that need to be considered.
The Corrimal Men's Shed enclosure looks like it's located inside their shed (blue doored cupboard)
4388256_orig.jpg
Our's is outside the shed and clad in dark olive Colorbond which was a requirement from the council to match the rest of the shed so on a hot day the structure soaks up heat.
We insulated it for heat and noise but that also prevents the heat getting out when there's no air flow..
EncOpen.jpg

The Corrimal compressor also looks like a 2.5 to 3HP unit compared to the 7.5HP unit in our enclosure.
Unless there's a leak in the system the pneumatics should not be using much air flow.
Do they use their compressor for anything else?

What this highlights is the benefits of automated gates and a VFD so other sheds take note, but not all sheds have ready access to funds to do the former.

Hi Bob,
When you were commenting on the two bandsaws pictured above you stated:

"The 14" unit has its under table collection located at the front of the cabinet.
It won't be quite as effective as having the extraction from the side but the there is no hinge on the lower cabinet door and the whole lower door comes away when the two lower tap like handles are undone".

It looks like its the other way around... I am currently fitting one of the BMH you made for me to this position, and just want to confirm that the best position is at the front of the machine.
Thanks.

Originally Posted by mase

Hi Bob,
When you were commenting on the two bandsaws pictured above you stated:

"The 14" unit has its under table collection located at the front of the cabinet.
It won't be quite as effective as having the extraction from the side but the there is no hinge on the lower cabinet door and the whole lower door comes away when the two lower tap like handles are undone".

It looks like its the other way around... I am currently fitting one of the BMH you made for me to this position, and just want to confirm that the best position is at the front of the machine.
Thanks.

There may be a confusion between what I mean by "front" and "side" of cabinet but its just terminology
This is the 14" BS and I call this under table collection as being "from the front of the cabinet".
The machine behind is the 16" BS and I call its under table collection from the "side of the cabinet"



For my BS at home, the better of the two is from the side like the 16" BS.
This is probably because the cross section of the Band itself , in relation to the air flow, is narrower when the air is collected from the side.

righto , thanks mate.

Not my men's shed. but Bunbury.

I helped them design their ducting system.
As you can see it's a big shed and they are likely to have multiple users.
They have 3 x 9" trunk lines feeding into a short run of 12" to their DC located outside
I coud not talk them into a ClearVue and they have gone for a used 4 bag 5HP conventional DC with some sort of automated filter shaker .

Ducting1.jpg

Ducting2.jpg