Dust collection

From DIYWiki

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Different types of dust and the different ways tools disperse it call for differing dust collection methods. Note that dust collection is quite a deep and complex subject, and it can be surprisingly difficult to achieve good effective collection. There are also many long term health risks associated with dust that should not be under estimated. This pages is by no means a definitive collection of data, please see some of the many excellent sites shown in the various links for considerably more detail.


Types

Dust collection at the point of generation, basically comes down to providing enough suction such that the dust is carried away in an air flow, which can then be filtered out before being discharged back into the work area. Less effectively, dust collection can also be applied to an area, in the form of air filtration - but this is really a backup to cope with a failure of earlier collection efforts!

High suction, low volume

The type of suction typically produced by vacuum cleaners. A moderate flow of air with a fairly large pressure drop. Can work well through relatively thin and long collection hoses, and the filtration is often well suited to finer dusts. Typically used to collect dust from smaller hand held tools.

Note that there are two common ways in which vacuum cleaner motors are cooled. The simplest type require adequate airflow through the suction path to provide cooling. Hence one must take care to not restrict the airflow as a result of using a tool with a small dust port on the machine. Better designs (typically "tub" type wet & dry machines) have bypass motors with a separate fan to generate cooling air for the motor. These are much better suited to dust collection duties on hand tools than the others.

Low suction, high volume

The type of suction more usually created by dedicated chip collectors. These move very high volumes of air at high speed, but with limited pressure drop. These collectors perform well with large diameter hoses and ducts, and are better suited to high volumes of dust and shavings generated by some wood working machines.


Filtration

Paper bags

Vacuum cleaner bags offer good filtration of even the most dangerous sub micron dust particles. However they also clog quickly and obstruct airflow if presented with high volumes of fine dust. This can happen in minutes with some dusts. Hence they are often at their best when pre-filtered with a cyclone interceptor.

Cloth bags

Cloth bags, often seen on old vacs, are coarser than paper. They're a lot less liable to clog than paper, but let more of the very finest dust through. Emptying them is very messy.

Dust collector bags

Large workshop dust collector bags are typically relatively coarse. This allows a high airflow volume but is not effective at catching fine dust such as that produced by sanding or wall chasing. Some machines have the option of a "felt bag" type top filter. These can be used with plastic sack collection filters for better collection of fine dust, however used this way their efficiency is greatly reduced to the point where their airflow is inadequate for the actual collection of the dust in the first place. The standard bags are ideal for collecting coarser dusts such as those produced by planing, thicknessing, and circular sawing.

Pleated filter cartridges

Typically found in wet & dry vacs, these tend to perform as well as a paper bag type filter however are far more robust when exposed to water or other liquids and sharp debris. Note however they also suffer the same clogging problem on fine dust.

Cyclone separators

Cyclones can be used as small separators to pre-filter the input to another suction device, or they can be built up into larger fixed workshop collectors, or they're used as the main filter in vacs. There are a number of very detailed web sites dedicated to building large cyclones, and Bill Pentz's extensive cyclone design site contains lots of original research and information and is required reading.

Note that with enough power and airflow a cyclone can be designed to capture pretty much any type of dust you are likely to create. The smaller pre-filter ones will tend to extend the life or paper bag filters and cartridge filters by quite a significant margin, but they won't necessarily capture all the potentially harmful fine dust.

Standalone cyclone vacs behave quite well with fine building dust, but with 2 issues: the plastic container gets scratched and dulled very quickly, and some cyclone vacs use small post-cyclone filters that can clog on large amounts of very fine dust.

No filter

Unfiltered dumping of air outdoors is a final option sometimes used for workshops and wood working equipment. Cold outdoor air has to come in somewhere to replace it, and a mess results, but it works. A patch of weeds etc can absorb the mess and incorporate it into the soil.

Aperture size

The maximum debris size a vac can handle is smaller than the hose size.

  • Most domestic vacs are limited by hose size, but a minority have much smaller apertures elsewhere in the system, making them unsuitable for a lot of diy work.
  • largeish debris tends to clump together and clog domestic vacs with low suction, high suction machines suffer this less often
  • Wood debris and shavings is better handled by large aperture workshop air filtration machines.


Tools

Angle grinder

These produce large amounts of dust, much of it fine enough to stay suspended in the air and clog all known cloth & paper filters.

Cyclones are effective dust catchers, but be aware that some cyclone vacs have post-filters that clog on dust residue.

Forced ventilation of the workspace is sometimes necessary.

Drill

Most drill dust isn't thrown into the air, making it relatively easy to collect. An envelope taped under the hole works reasonably well. There is also a small amount of very fine dust created when drilling masonry - this is often as fine as smoke particles, and is difficult to collect. Commercial "drill through" envelopes such as the Dust Bubble claim to capture at least some of this.

See-through plastic bowls are sold for ceiling drilling to catch the debris.

Where a lot of holes will be drilled, taping a vacuum cleaner hose to the drill catches a lot of it. Drilling shrouds are also available to connect to a vacuum and place over a drill site, however these often require the assistance of a helper to use effectively.

Drills with built in vacuum nozzle have been seen. On uk.d-i-y we lack experience with these so far.

Saw

Circular bladed saws often have built in vacuum ports. These typically collect around 50% of the dust, and often clog quickly. When used passively with the supplied collecting bag they're too often useless.

Any vac filter type can deal with sawdust. A high airflow vac is best to minimise frequency of clogging, old vacs with lower pressure and flow are better avoided.

Wall chaser

Produces the same dust as an angle grinder, but the built in hood & vacuum port makes collection much better - this however makes the job of filtration for the collector even harder.

Sander

Sanders produce fine dust, so paper filters and pleated filters are not great options. The average small sanding job doesn't produce a large amount of dust though, so such vacs are usable for light use.

Paint that might be old or leaded should not be sanded at all. Decoration painted with artists paints is likely to contain more toxic elements, and should never be sanded.

Planer

Wood shavings can be caught by any type of vacuum filter. A lot is produced, but its mostly not fine enough to be hard to deal with.

SDS

Same as drill, though chiselling can disperse the dust further, and a lot of chiselling can create a lot of dust.

Taping a vacuum hose to the drill can eliminate the majority of dust. The same job was carried out in 2 rooms, one with a cyclone vac and one without. In the without room, nearly everything was covered with dust. In the with room most of the need for cleanup was eliminated, with the only dust being near the tool.


See Also