Thread: Wet/Dry Vac for Dust Extraction

Originally Posted by Mooncabbage

. . . . ., my concern is whether it would be capable of dealing with fine dusts in the workshop.

Unless you pay the same amount for a vacuum cleaner (VC) as for a large dust extractor (DC) you simply won't be collecting fine dust from your shed. In fact you will be making things worse because most VCs make more fine dust than they collect. They do this because the high air speeds used minces coarse dust into fine dust and simply do not have the filtering capability to retain the fine dust. Even very expensive VCs eventually appear to become contaminated and become major fine fine dust generators. The only way I would consider using a VC inside my shed for wood dust collection is if it were inside an air tight box that was vented outside the shed.

In terms of shed space, if possible the best place for a DC is outside a shed on the wall opposite a major shed opening. Even a 1HP DC located outside a shed is better than most vacuum cleaners.

If you have a limited budget the best thing to do would be to have a large exhaust fan fitted to your shed and buy a quality dust pan and broom to deal with wood chips.

It's not actually a shed, it's a cellar/basement. 3 of the walls are underground and the other one has a door and a set of stairs down to it.

What about a "1HP Under Bench Economy Dust Extractor" from Carba-Tec? It's only very slightly more expensive than a shopvac from Bunnings anyway, and doesn't look enormous. Or alternatively the "1HP Economy Dust Extractor", which is the same price but works out taller, have to see if I can find space for it somewhere.

Originally Posted by Mooncabbage

It's not actually a shed, it's a cellar/basement. 3 of the walls are underground and the other one has a door and a set of stairs down to it.

OK - these are the worst situations for fine dust control as basements are serious dust traps that fill and retain fine dust.

What about a "1HP Under Bench Economy Dust Extractor" from Carba-Tec? It's only very slightly more expensive than a shopvac from Bunnings anyway, and doesn't look enormous. Or alternatively the "1HP Economy Dust Extractor", which is the same price but works out taller, have to see if I can find space for it somewhere.

I have only measured 3 of the under bench units for efficiency. Two were surprisingly efficient (better than a cheap vacuum cleaner) but the small bags result in very low flow (~120 cfm ie about the same as a vacuum cleaner). The other problem with the small bags is like cheap vacuum cleaner they block very quickly plus they are quite noisy. The 1HP economy unit has a bigger bag so is slightly better but I would only any DC if you can box it up and vent it outside the basement.

In terms of fine dust it sounds like you need ventilation far more than chip collection.

Is there any way you can provide air supply other than via the door? If you can then something like 2 x 12" bathroom exhaust fans located so that one fan forces air into the basement and on the opposite wall one fan draws air out. Better still would be two fans that exhaust air on the opposite wall to the door and let the door be the input air source. If there is no way to vent thru the 3 underground walls then the only remaining alternative is 5-6 m of 12" diam air con foil type ducting that you drag outside through the door and locate the end as far away from the door as possible.

If you cant locate your DC outside, then in terms of maximising the flow rate, a 1HP economy model inside an air tight box inside the shed and venting the box outside thru the door in the way I describe in the previous paragraph is a possibility.

There are no cheap out of the box solutions for fine dust - all low cost solutions require additional work and most expensive solutions usually require some work.

There really isn't much room for a dust collector immediately outside the workshop. Particularly the depth of the DC would be a problem, as the only place I could really put it would be immediately outside the door, up against the neighbouring fence. I could run a pipe up the outside wall to the roof for an intake/outtake.

I will take some photos later so it's easier to see what I have to work with. It's in total disarray atm as I am still sorting and organising it. Appreciate the advice so far (I didn't buy a shopvac :P).

Originally Posted by Mooncabbage

There really isn't much room for a dust collector immediately outside the workshop. Particularly the depth of the DC would be a problem, as the only place I could really put it would be immediately outside the door, up against the neighbouring fence. I could run a pipe up the outside wall to the roof for an intake/outtake.

You need about a 450 mm gap ( x 700 mm long x 1600 mm high to fit a 1HP.

I will take some photos later so it's easier to see what I have to work with. It's in total disarray atm as I am still sorting and organising it. Appreciate the advice so far (I didn't buy a shopvac :P).

Photos would be good.

Here are some photos of the workshop. Mind the mess, it's been used more or less as a store room for the past decade.

Basement 1.jpg
Stairs down to cellar

Basement 2.jpg
The longest wall, will have my workcentre in the centre, with benches along each side. French cleats on the wall above the benches will make for convenient, mobile storage. Also going to put some tube lights up under that beam, and take down all the axes and crap stored on it.

Basement 3.jpg
Once this wall is cleared, it'll have my lumber rack on it, along with a rack thing for sheet goods, and behind the door will be some masonite pegboard for storing fishing gear and the like.

Basement 4.jpg
On the right of the door here, I planned on having a bandsaw eventually. I'd put it on wheels so it could be moved around the shop. It'll be cleared off, regardless.

Basement 5.jpg
Opposite wall that I plan to have a low cabinet/worktop on, for drill presses, mini lathes, or anything else I get that doesn't require a huge expanse of wall.

Hi Mooncabbage,

That looks like a challenging, but worthwhile project.

Obviously you have considered that every piece of materials and equipment will have to go down those steps and every finished project will have to come out the same way. If that suits your chosen style of woodwork, then I am sure it will give you hours of pleasure.

You may want to consider something portable like a triton workcentre to cut larger pieces roughly to size outside the workshop before taking them in to finish them off. If you will be working with sheetgoods then an extension table would be good too.

Confined areas under houses tend to be real "dust collectors" anyway, even before someone sets up a workshop in them. BobL is right about it being a difficult area to set up effective dust collection. I cannot come up with anything better than his suggestion of a dusty in an airtight box vented out through the door with aircon ducting. As for using a 1hp dust extractor under these conditions; now that is a bigger compromise on his usual standards than I have ever sen BobL allow anyone else for their budget restrictions. I thought he would have been pushing for AT LEAST 2 hp. Can someone who lives near BobL can go around and see if he is alright, I am a bit worried about him .

Often those little basements areas do not have a real lot of access to electric power either and after you allow for the power used by the main tool there is not a lot left for the dust extractor to make it safe to use the main tool in the first place. In my own workshop I use a 2hp dusty instead of 3hp for that reason. I mention this because a lot of people do not take this into consideration when setting up shop and then incur unexpected costs of having extra power circuits installed to support the equipment they already have.

Hopefully at least some of my post is useful to you

Doug

Originally Posted by doug3030

. . . Can someone who lives near BobL can go around and see if he is alright, I am a bit worried about him .

As it happens I am not alright, I have a sinus and a chest infection with a nasty dry cough, and the antibiotics the doc has put me on make me nauseated.

I would not normally recommend a 1HP but if all one has to spend is a couple of hundred then 2 bathroom fans and a dust pan and broom will give the same airflow as a 1HP DC.

Mooncabbage, from your photos it is impossible to see if the 3 underground walls are anywhere near an external wall - my guess is they are not. This then restricts you to the air con foil ducting solution and bear in mind you will need as much distance as you can get between the intake and outlet. I recommend a 6 metre minimum.

Another problem you have near the door/stairs is that aircon. This means in summer it will generate hot air in the vicinity of the door so it means drawing in extra hot air into the shed. If you decide to use that area as a dust exit point the AC might get its heat transfer coils clogged with wood dust.

You may just have to wear a mask.

Originally Posted by BobL

As it happens I am not alright, I have a sinus and a chest infection with a nasty dry cough, and the antibiotics the doc has put me on make me nauseated.

I would not normally recommend a 1HP but if all one has to spend is a couple of hundred then 2 bathroom fans and a dust pan and broom will give the same airflow as a 1HP DC.

Hi BobL, Firstly commiserations on your current state of health. I wish you a speedy recovery. We all look forward to you getting back to your normal grumpy self and insisting on every shed having a dust extractor more closely resembling a nuclear powered ships turbine like the USS Enterprise and installing illegal nuclear fusion plants in our back yard to power them .

Seriously Bob, get well soon, I came home today with 6 metres of 150mm PVC pipe to upgrade my cyclone , main line and as many machine ports as possible, all because of your influence on the forum. Once again I am heading into a weekend of working on equipment rather than projects.but once it is all set up it will be great

Doug

Back!

The wall with the door DOES have access to the outside, via the stairs. The other walls are either definitely underground, or else are a split wall with the neighbour's property. I am however happy to pass a tube through the wall or the door, up the side of the house and up to the roof as an intake. However only one wall really has any kind of external access.

I realise my space is not ideal, unfortunately it's the ONLY space I have. It's this, or give it up, and tbh I'd rather not give it up :P

Power wise, there is a single double power point in the corner. However if I do need power, I don't think it would take the sparky a lot of work to run it out, as there is no true ceiling on the basement, just the floorboards for the room above.

At the very least, I want something I can use to handle the sawdust and maybe double to keep the shop clean. I'd consider putting one outside the door, but it'd need power, and I'm not sure about that. Also not sure if there is room, will have to measure it, but I doubt it.

Not really sure where I'd put the extractor fans. Are you suggesting just putting them on each end of a big bit of ducting?

PS. doug3030: I already have a triton workbench, but it's going to function as my tablesaw. It's an old MK3, and it's likely I'll eventually replace it with a WC2000, which I can upgrade to a router table etc (due to space requirements). I've calculated that the longest cut I can make is 1.8m. Large sheet goods will have to be ripped to size, probably with my handy dandy 7 1/4" Makita circular saw. I think that should be more than enough for what I plan to do, which is probably going to be to start with simple boxes and chests, and then maybe do some chairs or cabinets. I'm interested in older style furniture making. I want to try parquetry, marquetry, as well as using nice veneers, hopefully some I make myself, and also eventually I'd like to do some relief carving.

Originally Posted by Mooncabbage

Back!
The wall with the door DOES have access to the outside, via the stairs. The other walls are either definitely underground, or else are a split wall with the neighbour's property. I am however happy to pass a tube through the wall or the door, up the side of the house and up to the roof as an intake. However only one wall really has any kind of external access.

Using a chimney is a great idea but you should consider the following
- can you still get a ~5 m separation between intake and exhaust?.
- using a chimney as an intake means

* the air coming down the chimney will be fighting against rising warm dusty air generated inside the shed
* As any breeze passes by a chimney it produces a Bernoulli effect which produces a lower pressure inside the chimney which draws air out of the chimney
* the exhaust has to be at the door which means the door way and stairs will accumulate some fine dust as opposed to it being dispersed by a chimney.
* it will be under negative pressure so something cheap like air con foil ducting will not work as it will collapse on itself so something like PVC pipe will be needed but it should still be of large diameter or it will restrict flow. If the DC uses 4" ducting a chimney should be made of 6" ducting. and a 6m length of 6" ducting will cost about $50 and fittings cost about $20 each.

Whatever the case I admire your tenacity to solve this problem.

Well, I'm putting garden beds in the area opposite the door, above the stairs. Perhaps I could vent my exhaust into those? So long as the heat doesn't kill the plants, they'd probably be not half bad filters. I'm going to compost and feed them the bigger bits of sawdust anyway.

In which case, is there any point having an intake chimney, or should I just intake from the room? That in itself might provide sufficient airflow, if the room gets air in through the door, which is sucked into the DC, which is pumped away into the vegie garden.

Originally Posted by BobL

a 6m length of 6" ducting will cost about $50 and fittings cost about $20 each..

I bought a 6m length of 150mm pvc pipe yesterday. Prices in my area were actually between $71 and $90. Maybe they are cheaper in the west?

Originally Posted by doug3030

I bought a 6m length of 150mm pvc pipe yesterday. Prices in my area were actually between $71 and $90. Maybe they are cheaper in the west?

Yep it looks like it's gone up everywhere, I just checked my supplier and his best price is now $71 + GST. I can't believe I paid $49 inc GST just 12 months ago. Really glad I did mine when I did as I ended up using 2 lengths.