Thread: Clearing the air

Originally Posted by arniew

My shed has venting built into the eaves but I can't put in extra venting or even get a cross breeze as it is a rental with doors that open at one end and no other openings. I can have 3.5m x 2.4m open towards the south (half my southerly wall) but I'm concerned about venting if the breeze is from that direction (as it probably is half the time).

I was wondering if large fan (or breeze from the south) and a room filter in the eaves at the north end would be a good solution?

Most important is to vent the DC outside - is that still possible?

If so that will act as a ventilator to get dust out and unforced air can come in through the doorway.

But you cannot let air in from near or around the DC outlet to the outside. Any eaves or air pathway near the outlet will have to be blocked off.

Maybe posting a diagram showing your setup/labout and limitations will help to better arrive at a solution?

Originally Posted by BobL

Most important is to vent the DC outside - is that still possible?

If so that will act as a ventilator to get dust out and unforced air can come in through the doorway.

But you cannot let air in from near or around the DC outlet to the outside. Any eaves or air pathway near the outlet will have to be blocked off.

Maybe posting a diagram showing your setup/labout and limitations will help to better arrive at a solution?

Thanks for your interest Bob.

I can cut a hole in the Northern wall for the DE duct providing I repair at end of lease. I'm reluctant to pursue too many mods, but that seemed the most important.

I've used SketchUp to figure out machine layout and have attached that. The doors (showing the open area in the south wall) are overlapping sliding doors, so the opening could be to left or right. The wall to the west is internal and the doors shown give access to a couple of rooms that are not part of my workshop area. I can ensure any ventilation on the northern wall is blocked to keep the dust outside. I recall your advice from some years ago re DE placement away from air that comes into the shed.

The pipe disappearing through the wall at the north gives a rough location of air out to the DE

shed layout-dust.jpg

OK - that makes sense.
If you are cutting a hole in a wall for the DC outlet then doubling the size of that hole and putting a vent fan driving air out in the extra hole would be the way to go. Even a decent size bathroom type fan is better than nothing.
I would block up any eaves along that wall with the hole in it.

Originally Posted by arniew

I can cut a hole in the Northern wall for the DE duct providing I repair at end of lease. I'm reluctant to pursue too many mods, but that seemed the most important.

I have the same constraint, and made a 6 inch hole just under the eaves for the duct to go out to the DC, and am planning to fit a cheapish bathroom extractor fan into the hole when I leave, rather than try to brick it back up. I reckon no matter what the new tenant uses the garage for, an extractor fan will not be a negative, and may well prove to be useful.

I found some time last week to build a few 150mm blast gates. Next up is the BMH jig. I will post photos on that soon.


Sent from my iPhone using Tapatalk

A number of online ducting installers recommend taping joints with aluminium tape. Anyone got sensible advice on this?


Sent from my iPhone using Tapatalk

Originally Posted by arniew

A number of online ducting installers recommend taping joints with aluminium tape. Anyone got sensible advice on this?

Leave it for a few months before you do that as invariable you will want to mess with it!

Originally Posted by BobL

Leave it for a few months before you do that as invariable you will want to mess with it!

[emoji106]


Sent from my iPhone using Tapatalk

I have some 6" flexible hose from carbatec but I'm not sure 'flexible' is a great descriptor. Does anyone know a good flexible hose I can buy?

I have a Jet jointer/thicknesser that needs flexy hose so I can change modes. I might also look at a long hose for vacuuming.


Sent from my iPhone using Tapatalk

Originally Posted by arniew

I have some 6" flexible hose from carbatec but I'm not sure 'flexible' is a great descriptor. Does anyone know a good flexible hose I can buy?

I have a Jet jointer/thicknesser that needs flexy hose so I can change modes. I might also look at a long hose for vacuuming.


Sent from my iPhone using Tapatalk

Lappa has a good lead to good quality flexy.

I am using larger diam. hoses from a couple of sources.

The first is grey in colour and is very flexible - I have it in 5" and 50mm
IMG_0664.jpgIMG_0665.jpg

My only concern is the very thin wall section which can be fairly easily punctured so I wouldn't be dragging it over the floor or obstacles. It actually got punctured when tightening a hose clamp.
I've bought it from Hare and Forbes and Timbecon.

https://www.timbecon.com.au/extracti...ible-dust-hose

The second is thicker walled 160mm PVC Flex Medium hose from Advanced Duct Systems. It's listed as extremely flexible and small bend radius in the produce sheet.
I know I'm comparing two different size hoses (125mm vs 160mm) but in my opinion, its probably not as flexible as the grey pipe, its heavier, but it's good re non damage where it is attached to machinery and dragging on the floor due to it's wall thickness.

IMG_0668.jpgIMG_0669.jpg

http://www.ductsystems.com.au/PDFSpe...r%20Medium.pdf

Cheers.

I agree here with most. Venting outdoors is a great idea - but you still probably want to catch your dust so you can deposit it where you want it rather than it simply blowing all over the place. That stuff can make people itch and really cause serious allergy problems.... Better to bag it and then pour it out back in the woods or in your flower beds than simply blowing it into the wind.

Next thing.... What is your average wind direction? This should be taken into account for the choice of where to put the collector.... You would prefer the dust to generally blow away from your shop and house rather than into it...

Another thing to think about... How will you replace all this air that is being pumped out of your shed? If 500 SCFM is going out - you have to let another 500 SCFM in somewhere.... I would figure out some sort of filter inlet (if nothing more than an AC filter you could stick over an open window somewhere) so you don't fill up the shop with bugs, leaves, and sawdust exhaust....

Another thing.. Do you currently have any sort of climate/humidity control in the shop? If so - is your system designed to handle all this new unconditioned air coming in? Maybe not a problem, but my shop has an AC unit and a dehumidifier....

Hi truckjohn, I agree about the need to contain the dust outside. That is the plan- to use an old water tank. Thanks for your thoughts.


Sent from my iPhone using Tapatalk

Originally Posted by truckjohn

I agree here with most. Venting outdoors is a great idea - but you still probably want to catch your dust so you can deposit it where you want it rather than it simply blowing all over the place. That stuff can make people itch and really cause serious allergy problems.... Better to bag it and then pour it out back in the woods or in your flower beds than simply blowing it into the wind.

I think you misunderstand what sort of dust that is being vented outside. We don't advocate blowing all the saw dust outside so Folks still need to collect the saw dust using filter bags or cyclones. Thus 99% or thereabouts of the dust is collected and disposed of in an appropriate manner. The dust that is vented outside is largely invisible with most of it riding on air that has been warmed by machinery including the dust extraction process so it rises and is quickly diluted into the atmosphere.

Next thing.... What is your average wind direction? This should be taken into account for the choice of where to put the collector.... You would prefer the dust to generally blow away from your shop and house rather than into it...

This is a good point. More importantly than just blowing backing a shop is it being sucked back into a workshop which is why just venting a DC outside a door does not work so well. I said above this is super fine invisible dust that is warmed and rises fast even when vented slide to the ground. How do I know this? Because I have access to the testing gear and have done extensive testing in this area.

Another thing to think about... How will you replace all this air that is being pumped out of your shed? If 500 SCFM is going out - you have to let another 500 SCFM in somewhere.... I would figure out some sort of filter inlet (if nothing more than an AC filter you could stick over an open window somewhere) so you don't fill up the shop with bugs, leaves, and sawdust exhaust....

A standard AC filter will not prevent the sort of fine dust that is exhausted getting back into the shed. This fine dust will straight through these types of filters. However my testing has shown that provided the major air inlet (e.g. door or window) that allows air into a shop is on the wall opposite the wall where the fine dust is being vented, very little fine dust gets back into the shop.

Another thing.. Do you currently have any sort of climate/humidity control in the shop? If so - is your system designed to handle all this new unconditioned air coming in? Maybe not a problem, but my shop has an AC unit and a dehumidifier....

In Australia very few folks would have any sort of AC. If they have AC, it may be Evaporative AC which pumps huge volumes of air though a shop anyway and with the air inlet usually being above the shed may lead to problems pumping fine dust back into a shed so judicious placement of the AC inlet and the DC outlet is needed.

Some folks (like me) have refrigerated AC and I cannot continuously run my AC and DC and achieve any sort of reasonable climate control. This means on really hot days I try to do the dustier stuff in the cooler mornings and then by around 10:30 am I stop using the DC and switch on the AC and undertake fewer tasks that need a DC. The AC eventually cools not just the air but the stuff inside the shop. This means I can use the DC in short (minute) bursts if required and while it does remove a significant amount of cool air, the AC recovers the room temperature quickly because all it has to re-cool is the air and not the whole shop.