Dust extraction: Trend T30AF and...

[matt]

I've been browsing and noticed a number of members own the Trend T30AF vac and a.n.other dust extraction machine too. Often the second extraction machine tends to be the 4" hose variety.

Whilst it's potential limitations are fairly plain to see, the Trend T30AF is particularly well rated as an extraction method and mine seems to do a reasonably good job.

I'm curious to know what benefits are derived in practice from the 4" machines. Chips from a planer/thicknesser seem like one area where the Trend would fail miserably (but I don't own a P/T so speculating).

Is there a significant difference in performance on, say, a bandsaw?

Cheers

 

[Rattie]

I use a T30AF for powertools and a HA3210 for machinery. The T30 was pretty useless on the bandsaw, because it didn't keep up enough mass airflow through the case to keep the dust "on the move". The Scheppach moves so much air that anything venturing down into the bottom case gets sucked out. Some bandsaws have an extraction point just under the table where a vac type extractor like the T30 might stand much more of a chance.

For routers and portable saws like jigsaws and the Festool guiderail saw, the T30 is ideal. I intend to make a catcher duct for the SCMS so that I can use the huge airflow of the scheppach to grab its output, which can get a bit fountainous!

 

[Steve Maskery]

Matt
Generally speaking, you need both types of DX in the workshop. They are referred to HVLP and HPLV.

The Trend-style is HPLV or High Pressure Low Volume. It has a good suck for fine dust like that from routers and sanders and the like, but it doesn't shift a lot of air.

A 4" machine is HVLP, or High Volume Low Pressure. It shifts a lot of air, but not at the searing speed of the Trend. This is more suitable for P/Ts, spindle moulders and such like, where you are trying to keep a large volume of waste material on the move.

It's not an Either/Or, I'm afraid, it's Horses for Courses.

Cheers
Steve

 

[Boz62]

Due to lack of planer, I've stayed with HPLV, a single motor Camvac in my case. On the bandsaw, this is useless on the port on the lower case, but it works really well when sucking from around the blade just under the table. Here was my solution to this. In this method, the aim is to use high speed air to strip dust from the blade before it goes anywhere near the guides or lower wheel.

So to answer your point Matt, I feel that for a bandsaw, HPLV is perfectly suitable, with a little improvisation, but I agree that for a P/T I'd want to go with a HVLP big beast due to the much higher volume of dust and chips.

Boz

 

[matt]

I do wonder how much benefit I would derive from a HVLP extractor. I have the bandsaw, tablesaw, table mounted router, and everything else is hand tools.

The tablesaw has no extraction ports - just a big hole underneath where the heavier stuff goes whilst the dust fills the workshop (I suspect after being fired downwards via the blade and billowing out from underneath). I'm guessing that if I block up all the holes and vacuum with the T30 via a port from underneath then I may create sufficient vacuum inside the cabinet to draw the dust in to the T30? Or is this where an HVLP would be useful for dust in the same way as it is good for chips for a P/T?

 

[Boz62]

My feeling Matt, as a non CS user, is that you'd be in the same position as using an HPLV on a bandsaw lower port - not very effective. With HPLV you really need to get a nozzle closer to where the dust is produced. If you suck on the whole cabinet there may be too much leakage around the blade to get the dust moving from the cutting edge with the HPLV? And with with the adjustable blade in a CS it's more difficult to improvise a nozzle close in?

Boz

 

[Rattie]

There are two main issues.

Firstly HPLV vacs can have trouble collecting large chips moving at speed, because a) they don't spend very long in the airstream and b) they can in extremis block the nozzle or hose.

Secondly if dust doesn't pass through the volume of air about 10 x 10 x 10cm in front of an HPLV nozzle it's gone. So if you have a large area sander, a 10" - 12" tablesaw or SCMS blade without super tight sheathing around it then a high pressure vac is not going to do a great deal.

 

[matt]

Possibly a stupid question but here goes... If an extractor has a 4" pipe does that automatically make it HVLP? I figure it would because the diameter of the hose would reduce the velocity etc.

However... the Camvac was described as HPLV but there is an option of hose diameters to I figure it could be both?

But... if I adapted my Trend (not that I have any intention of doing so) to 4" (including the port) I doubt it would automatically equate to HV.

And then the chip collected style have massive induction motors with large fan blades moving a lot of air - true HVLP.

The point being... Can you automatically assume a large hose = HV?

(Almost forgot... I've also seen it said that you should not obstruct a HV cleaner in any way but some have adapters to smaller hose diameters which is, essentially, obstructing the flow of air.)

Oh, and another thing... I may have the option to install the extractor outside the workshop. Anyone else done this? I presume it means it's not so important to worry about the filter performance (i.e. 0.5 micron) on the basis that the harmful dust will enter a moist atmosphere and be rendered harmless quite quickly?

 

[cutting42]

Possibly a stupid question but here goes... If an extractor has a 4" pipe does that automatically make it HVLP? I figure it would because the diameter of the hose would reduce the velocity etc.

Hiya

Not stupid at all. The defining factor for HVLP or HPLV is the design of the motor/fan. A high pressure motor/fan is like a domestic vacuum cleaner albeit larger and more robust. A HVLP uses an impeller which can move loads of air but the design precludes generating higher vacuum pressures.

I have a Record DX5000 with a 4" hose system but it is a HPLV system with 2 motors. It generates enough airflow to work with my PT and table saw (although not as much as a true HVLP system). Crucially it can cope with a hose reduction to 2 inch or 1 inch for power tool extraction as well. The best compromise for my situation. The Camvac twin and triple motor extractors also work well I am told.

 

[matt]

Thanks for the clarification. I'm guessing that getting down to 0.5 micron filtering performance requires HPLV to push the air through the filter. The "lazier" HVLP rely on massive paper filters to achieve the fine filtering capabilities.

Brings me back to the idea of putting a HVLP in a shedette outside the workshop so the hazardous dust ends up outside in the shedette.

 

[OPJ]

Another thing to remember is that HVLP extractos decrease in efficiency (airflow) once you start reducing the inlet or hose diameter. With a HPLV machine, this is less of an issue and you'll still get good performance in the right situations.

 

[matt]

Sounds to me as though there is no point in me replacing my Trend with anything less than a twin motor (e.g. DX5000). Alternatively keep the Trend and go for a chip extractor for volume with a fine filter add-on or put it outside. I guess the Trend is higher up the league than I thought.

 

[Boz62]

If you are going the outside route Matt, you could just use a cyclone with a large-ish blower and no filter - just blow it outside. Like HVLP, cyclones don't work well when throttled down, but they are ideal for large volume stuff like planers, and you still have the Trend for hand-powertool and "small" work anyway. The only downside, apart from space, is all the warm air you are sucking out of the workshop in the winter .

Boz

 

[matt]

Good point about the warm air in the winter although quite nice in the summer. I'd not be happy about blowing the dust straight out in to the atmosphere. I realise that the moisture will deal with it on some level but it's not going to be too nice going everywhere beforehand.

I've come to the conclusion that there are three types of workshop extraction:

1. High Volume Low Pressure (HVLP) - uses one big bladed impeller to physically move lots of air at a steady pace but cannot be throttled down for small tools.

2. High Pressure Low Volume (HPLV) single motor - Good for small tools or where you can get the extraction up close to the action.

3. High Pressure High Volume (HPHV) twin+ motors - Moves a lot of air because of the cumulative effect of the motors. Can be throttled down but can also run a 4" plumbed in system too.

Option 3 sounds like the best solution for the small workshop (as per earlier suggestions in this thread).

By contrast, single motor 4" vacs are, to some extent, a bit of a nonsense or useful in only limited applications (e.g. lathe work where you can get the mouth up close to the work). 4" inch ports on machinery are invariably designed for the bigger movers.

Whilst out of my price range, a twin of even triple motor Camvac 386 seems like a suitable monster to do the job :lol:

 

[matt]

This one from Axminster sounds like a good package except flow is surprisingly low for a twin 1200w motor machine - 83 l/sec. My Trend is 55 l/sec and both Record and Camvac >100 l/sec for their twin motor machines. Nevertheless, read the description of the machine and it sounds like you get a lot for your money, including an option to exhaust out of the workshop which I think is a really good option.

 

[RogerS]

The other thing to think about is how large the chip/dust collector bag is, how easy it is to change or remove and how quickly you think you're going to fill it up. That's one of the reasons why I didn't like the Camvac I bought - filled up too quickly and because it's in a tin, you don't know how full it's getting. And it was a faff to transfer the stuff from it into something else.

Oh yes..noise. Don't forget that. Anything with an induction motor is going to be a lot quieter than anything with a brush motor.