Thread: Anybody got one of these vacuum heads?

I have and found them to be a major PITA.

Getting the hose to stay on is quite hard.

I just use the elephant truck by itself now, I tuck the main part under my arm.

It might be good to make a thing-on-a-stick to hold the end of the truck to wiggle it around better.

Got one, fully agree with woodPixel but it does work and it doesn't clog on big pieces like hand plane shavings but you have to look out for small offcuts.

Its a real wrestle using a 4" vac hose which doesn't like to rotate as you move around and as I don't have a long hose I need to drag my DC around.

Only use it when I have large lumps to pick up, the rest of the time I open both ends and use a leaf blower.

Ditto to above comments ... the hose from the DC is heavy and not all that flexible .. I use a broom and then the hose directly to suck up the dust ... if there any hand plane shavings then the shovel and brush are best ... the plane shavings clogs the screens on my DC.

The night before painting I use the shop vac blower to blow the floor (windows open) and then in the morning use the sho vac on the floor .. it can reach places the big hose cant get to.

Rob

Compressed air works very well too.... But seriously dusty! Open doors and time are mandatory.

Thanks for the replies guys. I'm thinking I might give it a miss for the moment and focus on eliminating the stuff in the first place when I rebuild the workshop.

Better go get sweeping.

Cheers!

Just a reminder that trying to push fine dust is like herding cats. All you can really hope to do with blowers/compressors.brooms is lift some fine dust off surfaces. Adding forced ventilation or if there is a good breeze blowing and lots of doors and windows open will make a difference in removing lifted dust. The question is how much>

The half residence time in air for fine dust is around 25 minutes. This means, provided there are no further disturbances, every 25 minutes the level of fine dust in the air will halve.
Depending how much dust there is on a floor, sweeping or blowing can raise the dust levels in a shed to over 100 times above recommended heath and safety levels. In the first 25 minutes the level will fall to 50x, second 25 minutes it falls to 25x, 3rd 25 m = 12.5X, 4th = 6.25, 5th = 3.125, 6th = 1.56,
Only after the 7th 25 minutes (~3 hours) will the level be nominally below recommended OHS levels.
Thus leaving doors and windows open overnight so that as much as possible can ventilate out of a shed is a good idea. However, this is not always possible for security reasons.

Calculations for venting a shed with a light breeze are complex.

A light breeze is defined as around 5-10 ft/s or 300 to 600 FPM but that is not what gets into and out of a shed in a typical suburban back yard which is often protected by fences, vegetation and other buildings.

Some other factors include, size of the openings, orientation of breeze direction with window and door openings, alignment of window and door openings to each other and location in a shed. The internal height of a shed and heights of windows and door openings are also important as fine dust will rise right up to the top of the ceiling and with most doors and windows no taller than about 2.1 m above the ground. Any breeze entering a shed will follow the line of least resistance and so may only travel along the volume directly between openings leaving the rest of the shed relatively unventilated. The net effect is that determining air speeds though buildings is complicated but what ever it is, it is always less than the external air speed.

Case 1: A personal door and a 1m x 1m window in an adjacent wall in 6 x 4 DIY shed surrounded by fences and vegetation, can achieve ~1/10th of the gentle breeze air speed i.e. 30-60FPM.
Case 2: A full width roller door and 2 , 1x1m window in an opposite wall of the same size shed free of surrounding obstructions can achieve ~1/2 of the air speed.

In both cases the smallest opening determines the actual air ventilation

Case 1: 1 x 10 sqft window, At 30 - 60 FPM lets call it 45 fpm x 10 sqft = 450 CFM (about the same as a small DC with clean filters) this is worth doing especially if it is constantly open. But remember it does rely on the breeze always blowing.
A 6 x 4 m x 2.7m shed has a nominal volume of 20x13x9 = 2340 CuFt.
In the first minute 450 CuFt of air is removed but 450 CuFt of dust ladened air is not removed because about half the clean air coming in also goes straight out so the effect is only 225 Cuft of dust ladened air is removed.
To completely vent the shed thus takes 2340/225 or ~ 10 minutes (this is actually quite good) but during that time about 1/4 of the dust would have settled back down onto surfaces before being removed.

Case 2: 20 sqft are of window At 150 - 300 FPM lets call it 225 fpm x 10 = 2250 CFM a bit more than a large DC with clean filters) this is REALLY worth doing especially if it is constantly open and the breeze is blowing.
As above, the shed is the same volume i.e. 2340 CuFt.
Using the same calculation as for case 1 this time in the first minute, 1125 CuFt of dust ladened air is removed.
To completely vent the shed thus takes 2340/1125 or ~ 2 minutes (this is much better) because during that time < 1/10 of the dust would have been able to settled back down onto surfaces before being removed.

These calculations are only approximate but it shows how effective ventilation can be, provided the breeze is actually blowing.

The above calculation does not take into account something called preferential flow between the openings especially in a tall shed. This is where a sort of tunnel or air current is established between openings.
This has the effect of rapidly cleaning the air in that tunnel but leaving dead zones in the shed contaminated. This is especially the case for dust driven high up near the roof by sweeping, blowers or compressed air.

Thus, door and window based ventilation can still leave the air volume above a height of ~2.4m contaminated, at least in the short term. The dust settling calculation described above indicates that the doors and windows would need to be left open for about 3 hours to allow the dust to settle into the breeze zone/tunnel so it can be swept out. If you just have the doors and windows open only while blowing dust around and then close them immediately afterwards, then you won't be venting much fine dust.

This points to the best position for ventilation to be at the highest point in the roof line. Whirlybird fans don't move a lot of air but at least they can be locate at the optimum dust removal point in the shed.
Apart from extraction at source, forced extraction at the roof line is really the best way to go. For a small shed a couple of bathroom type fans are low cost and unlike breezes always available.

Originally Posted by chode

Thanks for the replies guys. I'm thinking I might give it a miss for the moment and focus on eliminating the stuff in the first place when I rebuild the workshop.

Better go get sweeping.

Cheers!

Good idea.

Just a reminder that shop vacs that debt back inside a shed can seriously increased the amount of fine dust in workshop air.
Even HEPA filtered units unless well maintained and regularly checked can have problems.
If you use a shop vac, just like a DC it is really worth mounting it outside a shed.

Just a reminder that shop vacs that debt back inside a shed can seriously increased the amount of fine dust in workshop air.
Even HEPA filtered units unless well maintained and regularly checked can have problems.
If you use a shop vac, just like a DC it is really worth mounting it outside a shed.

Thanks Bob,

In my case the workshop is going to be in the house (soundproofing walls as best I can) but due to minimal boundary clearance between the workshop and fence (750mm and I'd rather keep it for access) I will be placing the DC inside the shop but my thought was to enclose it in it's own room or cupboard on the external wall and somehow vent it outside that way.

What are your thoughts on this? I'll attach a pic of the plan to illustrate. The dashed line on the right is the boundary.

workshop.png

Originally Posted by chode

Thanks Bob,

In my case the workshop is going to be in the house (soundproofing walls as best I can) but due to minimal boundary clearance between the workshop and fence (750mm and I'd rather keep it for access) I will be placing the DC inside the shop but my thought was to enclose it in it's own room or cupboard on the external wall and somehow vent it outside that way.

What are your thoughts on this?

I'll attach a pic of the plan to illustrate. The dashed line on the right is the boundary.

Can't see anything in the drawing other than a building plan. Was there something I missed?

Yeah sorry that was it ha. I was just wanting to illustrate where the workshop will be in relation to the boundary and the rest of the house. If I were to house the DC in it's own internal room within the workshop would it be best to have it up against the external wall would any corner be fine?

Not wanting to confuse your decision, but I have one of these and find it works well. I use the "Super Flex Dust Hose" from Carbatec and find it is flexible and does not inhibit movement. I use quick release thumbscrew clamps and have no issue with it coming off and it is quick to change to back to machine ports. I am in the process of changing over to 6in lines to machines and so will leave the wand connected and even easier to use once complete.

Bauldy