Dust collection bags are the last thing many people consider when choosing a dust suppression strategy. They shouldn’t be: using efficient bags is very important. You can undermine your system by neglecting them.
Inefficient, overfilled or dirty bags will reintroduce dust back into the air or into parts of the extractor where it shouldn’t be. Filters are often the first thing to suffer, and that means you could soon be wasting money running an extraction system that isn’t extracting at all. Strain on the pump and motor also shortens their lifespan.
Do You Need a Bag?
If your bags sit inside a removable canister, you can sometimes collect dust directly into the canister without a bag. If you’re dealing with damp materials, that’s often the recommended method.
However, bagless canisters are inefficient at catching light, dry materials. You will soon find dust contaminating other areas or re-entering the air. You also have no means of containing the dust when you dispose of it, and that could breach Health & Safety regulations. Many extractors must comply with the Machinery Directive (2006/42/EC), especially IEC/EN 60335-2-69 Annex AA.
Whether relying on a static spiral duct extraction system from https://www.dustspares.co.uk/ductwork-parts/galvanised-ducting/galvanised-steel-spiral-duct.html or a portable extractor, not using appropriate bags could get you into hot water.
Plastic Dust Bags
Air doesn’t pass through plastic, so they have vent holes through which dust often escapes. They are great for heavier non-toxic materials such as woodchips, but if the dust is easily airborne or potentially toxic, these bags aren’t suitable.
Their advantages are that they’re cheap, tear-resistant and moisture tolerant.
Air passes through a fleece bag almost as easily as through the filter, so the bags assist the filtration process and save money on filters. Being porous, they can be closed snugly over the hose. That makes them excellent at containing all the dust in operation and when you dispose of them.
Although more expensive, they are the best solution for fine dry particles and also recommended if your extractor lacks an automatic filter cleaner.
Paper Dust Bags
Like fleece, paper is porous so provides similar advantages. They are not quite as efficient and can’t be washed, but they’re cheaper.
The main disadvantage of paper is that it can split or be punctured. Moisture makes them less porous and more likely to split.