ondablade

Thanks for coming back Asa. I'm happy to agree that your piece took an important step in bridging the gap in DIY dust collection practices.

It's clear too that there is a reality (with it's origins in many years of practice) that has to be taken account of - people simply won't make the jump in a single step, and that anyway the suppliers are only starting to respond to effectively to more sophisticated needs.

The need (or not) for 5HP is quite highly dependent on the length of your ducting runs, and on how much cushion against motor overloading you want in case too many machines are connected at once. Chances are too that there's scope for machine hooding arrangements that will reduce the CFM (and hence the HP) required for effective fine dust collection.

Pardon my pushing the issue, I'm not in touch with the total picture anyway. I'm optimistic though about the prospects of getting the average woodworking punter up to speed on the technicalities of what constitutes a good system.

What gets people antsy I suspect is being faced with the need to bridge a technical performance, build time or cost gap that isn't feasible for them given what's available in the market.

The flip side I think however is the unfortunate reality that if there isn't some pressure of this sort maintained, that the industry will fall back into an unhealthy reliance on the status quo.

That if we don't keep some heat on that we'll all be congratulating each other on our state of the art dust systems in 15 years time, and wondering why we're wheezing while we're doing it....

ian

It's clear that my perspective may not be typical Asa, but the Tools and Shops issue no.223 was precisely what I had in mind when I commented about FWW's handling of the dust system issue.

It was a great step forward to see the fundamental need for HEPA filtration, and the consequent requirement for a cyclone (if you want to do this) nailed down in respectable print.

But was it a piece on the state of the art??? Cmon. It (a) wasn't representative in terms of what's out there in cyclones (it was remarkable photo opp for one manufacturer); (b) made no effort to separate the performance of the different solutions on fine fine dust retention; and (c) made no reference whatsoever that I could see to the other basic variable in achieving effective fine dust collection at a machine which is the CFM delivered by the system - which in turn is fundamental in sizing a cyclone and related parts of a dust system.

What for example determines the choice between the larger 5HP cyclone based systems you see about, and the more typical 2HP type? This is a huge issue - what's the point in fitting HEPA filters if your system is not capable of effectively capturing dust as it's produced, and is instead allowing the shop to fill with it? Both are pitched at similar small shop applications, which means that somebody is gilding the lily.

Here's more. While it in a basic way confirms that the cyclones do their job, what use is it to anybody to know that they can send 20lbs or whatever of dust through a given cyclone before the filter blinds when this is left unrelated to run time, distribution of particles sizes in the dust and CFM?

The CFM issue surfaces elsewhere too in the mag in the piece featuring a very lovely one man shop.

In what way does reducing the drop to a machine to 4in improve system efficiency? Without getting into the engineering my (basic) HVAC training suggests that a choke point anywhere in a low pressure (<25in WG) air system will due to incompressibility) act to significantly reduce the airflow.

I know it's common practice to see what looks like smaller branches to machines in industrial systems, but this is surely when multiple simultaneously running machines (each with properly sized drops) feed back into a common header - which is in turn enlarged to handle the combined flow?

Reducing to 4in dia may well get a low CFM or leaky system over the hump in terms of getting chips up the vertical, but overall it's going to substantially reduce system CFM and hence (with typical machine hooding) the effectiveness of fine dust collection.

I'm acutely aware that there's probably a gap between systems capable of delivering the sort of 1 - 5mcg/m3 (8hrs) air quality required in regulated industrial environments (in Europe anyway), and what the DIY guy often gets.

But surely it's time that this issue was called in public debate? There's a few pioneering manufacturers out there that have already shown that this gap can be bridged for us recreational guys too.

ian

I enjoy the consistently high production values, but quite honestly would prefer less gloss and more content - especially on high quality furniture making, and aspects of woodworking beyond traditional cabinet making.

The overlap into the business, industry and woodworking markets dimensions are left largely untouched which surely is a mistake - it's not a DIY home improvement mag.

Please concentrate on show and tell pieces in the context of specific projects which set the 'how to' in context - and which worry less about maintaining a short and snappy style than on effective communication of comprehensive information. Piecemeal 'how to'/'hints and tips' stuff is much harder to absorb or utilise too.

Please also get up to speed on topics like dust and chip collection. So far the magazine has consistently endorsed approaches that if not downright incorrect are certainly sub optimal in matters to do not just with the mechanics of dust collection, but also health and safety.

Finally. Please end the hard sell - the saturation bombing of those with or that had subscriptions etc. with sales material. It's become offensive and off-putting, and communications to this effect are ignored.

I took out a magazine sub a few years ago, but I won't do so again until it starts to feel like it's my choice as to whether or not to renew....

ian

I'd have to say that we talk a lot of ideologically driven hot air on the use of MDF, but when push comes to shove vote with our feet by using the stuff all over the place.

Like everything else in the world it's not bad, not inherently good. It just is. There's no one size fits all answer.

It's in the end a situation specific judgement call - there's arguments for and against it from almost every perspective.

The real game is surely to make good life and design choices - on the way to making beautiful and useful stuff while doing minimal harm.

The MDF issue will be sorted out along the way.

ian

Good going FWW for refocusing this piece - it caught my attention too in that it seemed to go against my limited understanding of the reality of the situation regarding safety and wood dust.

It's important, because it's not unusual to see people talk of these units as though they are a stand alone dust solution.

There are major issues with DIY/hobby level woodworking dust control practices anyway as a result of the gap between common perceptions/received wisdom, and the realities of wood dust safety.

This it would appear is in part the result of the sale for many years of low performing dust collection systems to the DIY and hobbyist market. Another factor is the fact that the truly dangerous sub 10 micron dust particles are invisible, and the consequences cumulative and usually medium to long term.

The result is that people struggle to understand why they should spend large amounts of money on high spec and high flow fine filter systems when they are not the norm.

'If THEY let it be sold/let us use it, then it must be OK....' - the classic disbelief that arises when realities conflict with perceived norms.

Following the uphill struggle waged by the likes of Bill Pentz http://billpentz.com/woodworking/cyclone/index.cfm (Bill's pages are a goldmine of information - but never a model of concise writing :-)) to bring these issues to consciousness and provide an alternative some manufacturers are responding - we're for example starting to see optional fine cartridge filters and the like offered as (sticking plaster?) options by some, and properly sized cyclone based systems by a few others.

There's also a sizable number of people out there who have taken control of their own situations and are running DIY and/or part purchased (http://www.clearvuecyclones.com/Order_Page.htm) installations based on Bill's data.

I'm part way through a DIY installation of a Pentz system, and chose this route as a result of the compelling safety argument, and excellent feedback.

I'd be much happier to see an end end to the fuzzy and qualitative 'gets the job done' style of magazine review of dust collection equipment - to be replaced with hard data based performance testing (in realistic situations) against TLVs.

In the case of the ducted dust systems that so far are the norm, and in keeping with the thrust of Bill's writing there are perhaps three basic questions that often get overlooked:

1. Presuming reasonable guarding and hooding arrangements - is enough airflow/depression generated around the point of work to prevent dust getting into circulation in the room? (the issue of duct and fan sizing)

2. Is the filter system fitted capable of preventing the recycling of the highly dangerous (and invisible) 10 micron and below dust particles into the room? (the issue of filtration capability)

3. Can the system hope to maintain this level of performance over a reasonable period of time in use? (the issue of the rapid filter blinding that seems to occur unless a cyclone or similar device is used to separate most of the dust and reduce the load on the filter)

The ability to test systems adequately does not come cheaply without considerable ingenuity and expertise, this must be a major consideration for the mags.

It seems to me though that this is pretty much a moral obligation for any publication that purports to serve its readership.

There's other reasons too. We're already all aware of the threat posed by heavy handed regulation to DIY and hobby woodworking. Wouldn't it be infinitely preferable to get the information out there on what comprises and adequate dust system so that market forces can sort this out in a much more finely nuanced way that leaves freedom of choice intact??

I'm not familiar with the programme, but looking around me here in Ireland these days where very few indeed have practical, technical or craft skills it's so obvious that there is a huge gap in our education.

Young couples all over the place, paying enormous prices to second rate 'craftsmen' for sloppy work that's actually a nothing. This on top of lots having got caught in the recession with enormous mortgages and so on.

It's really only those from some farm backgrounds, or who came from hands on families that are the exception.

Worst of all perhaps is the amount of psychological insecurity, technophobia and inability to see the role of technology in society - it's going i think to cost us dear....