Workshop Extraction

[user22161]

When I first kitted out, I got a Karcher shop vac for LVHP and one of these for the PT and bandsaw https://www.poolewood.co.uk/product/cha ... ctor-w685/ which is pretty quiet and worked well with one tool at a time and a short hose but no fine filter option. When I decided to add ducting (not yet got around to that), I sold that and bought one of these https://www.poolewood.co.uk/product/cha ... ctor-w691/ Obviously a lot more powerful, quite noisy and has a large footprint in a small workshop, can be supplied with a fine filter as well at about £90 extra. Also have Record AC400 air filter. In an ideal world, the dust extractor should be in shed outside the workshop, would avoid the need for fine filter but sucks heated air out.

 

[J_Ashley]

Thanks all for the advice. This has really helped me established what type of equipment I am after and how I should prioritise it, and has also given me some good ideas regarding which models to go for.

As I said, I am planning the extraction system for a upcoming new workshop, and so I am not in a position where I have to go out and buy today. With that in mind, regarding what models I ultimately purchase I might see if there are any good offers over the coming months.

Likewise, what are people's thoughts are buying extraction equipment second hand? I'd be looking at equipment in good condition, but is there still a chance that it could be past its best to the point of being less functional? Is extraction one of those things best bought new?

 

[Brandlin]

Likewise, what are people's thoughts are buying extraction equipment second hand? I'd be looking at equipment in good condition, but is there still a chance that it could be past its best to the point of being less functional? Is extraction one of those things best bought new?

There is very little to an extractor of any kind that can go wrong. Basically its just an impeller on a motor. Bearings can go - but are relatively easy to replace. Other than that as long as the motor is OK and the impeller is undamaged (spins without vibration) then you're ok.

 

[MikeJhn]

If you go second hand, do be aware that some of the cheaper units have plastic impellers, they will break eventually, look for a unit with a metal impeller.

Mike

 

[J_Ashley]

I’m looking at running a cyclone (e.g. Dust Commander DLX) with a collection bin in front the workshop vac. With that in mind, do I need to take any additional considerations when buying the vac (i.e. does a cyclone hamper power/airflow or filtration level) - in which case I might want to get a vac with a bit of additional performance knowing the cyclone will reduce it? Or is it simply a matter of putting it on the front and reaping the rewards?

 

[Sideways]

Yes, the cyclones do act as a restriction in the flow of air. Noticeably so, but the benefit of having a nice big collection device in front of the shop vac is quite a benefit when weighing up pros and cons.
I have not found a rigorous comparison of small cyclones vs the Thien baffle design but what I've read suggests that there isn't a great deal in it and the cyclone design creates marginally less loss of airflow / pressure (and I think it suggested the cyclones are comparatively better as systems get larger).
Take this with a pinch of salt but you might lose 30% if you put a cyclone separator in line.

Cyclones and baffles allow heavier particles to drop into the bucket. My small dust commander (the black anti static one) is great at separating out chips and shavings and catches plenty of fine dust from my 8" tablesaw. I don't expect it to catch all the dust from sanding so I keep a bag in the vac that I use it with. Because the cyclone catches all the bulky stuff the bags last for ages and this allows me to use a quiet, commercial vacuum with it instead of a larger, noisier shop vac.

 

[basssound]

Which vacuum have you got?
I've just bought a cyclone to use with a filter bag vacuum but I've not got the vacuum yet.

 

[Sideways]

Which vacuum have you got?
I've just bought a cyclone to use with a filter bag vacuum but I've not got the vacuum yet.

I bought a karcher T-201 used. They no longer make them. Liked it enough that I bought another. They are low and round, aimed at hospitals and hotels where cleaning has to be a constand background activity. The dust bag is long and wraps around the motor helping to reduce the noise. There's a nilfisk gd930 or some such that looks very similar but with a steel body.
My take-away is to buy something that has as low as possible dB noise rating. Very few machines are below 62 so i've never heard anything quieter than mine though they are out there. Some variable speed extractors quote good numbers but this is with suction dialled down. They are much louder at full power.

 

[J_Ashley]

A slightly different extraction topic - is it worth getting some form of bathroom style extractor fitted when having the workshop built? I realise it’s not going to be particularly powerful, but it might provide a extra option for refreshing the airflow.

I need to keep a watchful eye on humidity, so it won't be ideal to have to rely on leaving doors/windows open for long periods.

 

[MattRoberts]

You need to be careful when moving air around the shop. If the air isn't being forced directly through an appropriate filter, you're at risk of just moving around a lot of fine particles that would otherwise normally settle. That's why proper air filter systems have a huge filter on them - they move a lot of air, but they filter whatever air is moved

 

[J_Ashley]

Good thought - I didn’t consider that disturbing fine particles without suitable filtration would be a bad idea.

One thing I’ve not quite got my head around is the comparison of the ‘workshop’ air filter (e.g. Jet AFS 500/1000, Record AC400) vs the more ‘domestic' orientated ones.

The Jet AFS 500 is claiming filtration performance of 98% 5 microns in size and 85% 1 micron in size. Yet I see that there are domestic units claiming to be TrueHEPA which means 99.97% of particles 0.3 microns. However, the Jet model shifts between 360-600 m³/hr of air an hour, whereas these smaller domestic filters are much lower power are only perhaps only filtering around 70 m³/hr.

So, for an air filter which is the better trade off - high turn over of air but only filtering down to 98% 5 microns / 85% 1 micron in size, or a lower turn over of air but at (apparently) TrueHEPA levels?

I’m aiming to have a chip extractor and workshop vac that have filters to the 1 micron level (although I appreciate not 100% of dust will be captured at source), so I’m thinking it would be nice if the air filter pulled in these smaller particles that are slipping through the other extraction systems.

 

[user22161]

Record AC400 quotes 1 micron and will shift a lot more air than a domestic unit and I have a hard time believing claims made for a lot of "domestic" items. I was surprised just how much fine dust my AC400 collects.

 

[MattRoberts]

Good thought - I didn’t consider that disturbing fine particles without suitable filtration would be a bad idea.

One thing I’ve not quite got my head around is the comparison of the ‘workshop’ air filter (e.g. Jet AFS 500/1000, Record AC400) vs the more ‘domestic' orientated ones.

The Jet AFS 500 is claiming filtration performance of 98% 5 microns in size and 85% 1 micron in size. Yet I see that there are domestic units claiming to be TrueHEPA which means 99.97% of particles 0.3 microns. However, the Jet model shifts between 360-600 m³/hr of air an hour, whereas these smaller domestic filters are much lower power are only perhaps only filtering around 70 m³/hr.

So, for an air filter which is the better trade off - high turn over of air but only filtering down to 98% 5 microns / 85% 1 micron in size, or a lower turn over of air but at (apparently) TrueHEPA levels?

I’m aiming to have a chip extractor and workshop vac that have filters to the 1 micron level (although I appreciate not 100% of dust will be captured at source), so I’m thinking it would be nice if the air filter pulled in these smaller particles that are slipping through the other extraction systems.

Those domestic ones might claim very high filtration, but if they're so weak that they only 'capture' 10% of the air in the shop, that's 90% of the air with 0 filtration.

Personally, I'd rather have 75% of the air filtered to 1-5 microns than 10% of the air filtered to 0.3.

 

[Sideways]

Somewhere or other I read about the idea of 7 or was it 10 air changes an hour being a good thing to aim for when sizing these air filters. It always sounded sensible to me.

 

[MikeJhn]

Sorry wrong post

 

[J_Ashley]

Ok, it certainly sounds like air turnover is the measurement to prioritise.

One further question - why wouldn't Record/Jet simply offer a HEPA filter as an accessory to their existing units?

Is it simply that very few particles that size are produced, and therefore such a fine filter isn't really necessary? Or do finer filters significantly reduce that airflow of the machine?

 

[user22161]

Which HEPA rating? There's quite a range from H10 to H14 - 85% - 99.999% https://www.google.co.uk/search?biw=136 ... s_l=&pbx=1

 

[MattRoberts]

Proper HEPA filters are expensive and restrict the air flow more due to their density. Most vacs that advertise HEPA filters are probably bending the truth about their HEPA rating and efficiency for marketing purposes

 

[J_Ashley]

I guess I was thinking of something that would collect the majority of particles less than 0.5 microns, i.e. below what the filters on the shop vac and chip collector can do. I'm not sure what HEPA rating that would be specifically.

 

[PAC1]

I guess I was thinking of something that would collect the majority of particles less than 0.5 microns, i.e. below what the filters on the shop vac and chip collector can do. I'm not sure what HEPA rating that would be specifically.

That is a very hard ask. First the motor has to be capable of the air changes through a very fine and very big filter. Then you need to think about air flow in your shop. Just because you have a motor recirculating air does not mean all the air gets to go through the filter. It is quite possible that it will create its own little air flow system whereby 60% of the air gets recirculated 7 times an hour and the rest stays pretty static but still contains those particles. It is far better to maximise the extraction at source. Relying on an air cleaner is not a good plan unless you are a mechanical engineer and can design baffles into the room to ensure all the air is changed several times per hour.