Maintaining most of the machines in your shop - table saws, planers, band saws - means keeping them running at peak performance, so they'll do precise work. A well-maintained dust collector won't make your cuts more accurate, but it will help keep your shop cleaner and safer and, more importantly, help prevent damage to your respiratory system. Whether you own a portable chip collector or have a full central system, most collector maintenance is very straightforward: Empty the unit's bins/bags regularly and keep the unit's filters reasonably clean, and you're halfway there. Other regular maintenance steps, including checking the fan, vacuuming the electrical boxes and making sure hose and ductwork connections are tight, will assure that your collector will operate at peak performance for years to come.
Empty the Bag or Bin
By far the simplest yet best thing you can do to keep your dust collector running right is to empty its bag or bin regularly. Most portable collectors accumulate chips in either a fabric bag (or bags) or a disposable plastic bag . The latter are particularly handy, as you don't have to transfer chips before disposing of them. Unfortunately, it's all too easy to let sawdust pile up to the point where the entire collector is clogged up and suction drops to near nothing. Case in point: A local woodworker once asked me to check his dust collector, which he said had "simply stopped working." When I pulled off the lower fabric chip bag, I discovered
that it was completely full, and sawdust was densely packed all the way back to the unit's fan! Emptying and cleaning the unit's bags quickly restored the collector to full performance.
Before emptying your collector (or shop vacuum for that matter), always be sure and don a proper dust mask, to protect your lungs from fine dust that inevitably escapes. If your collector employs a drum as a dust bin, you can minimize raising a dust cloud by securing a plastic trash bag to the outer rim of the bin with a car-rack-type tie-down strap (let the bag fill with a bit of air before you attach it). Once the bag is strapped securely on, tip the bin over carefully, then slowly invert it to transfer its contents to the bag. Tap the sides and bottom of the drum, to dislodge any sawdust that's stuck inside. Let the bin sit for a minute or two, to let the dust settle, then unstrap the bag, lift the bin off and seal up the top of the bag.
Clean the Filter(s)
There's a very basic dust collection principle that's often forgotten: The air sucked into a collector also has to exit it for collection to take place. No matter how powerful a collector's fan and motor are, if the unit's filters are clogged, airflow will diminish significantly and sawdust collecting performance will suffer. Cleaning reduces the amount of fine dust built up on the inside surface of a filter, hence allowing greater airflow through the filter media. Cleaning procedures vary depending on the kind of filters on your unit. Bag type filters are the easiest to keep clean: A regular light shaking will knock enough sawdust off the inside of the bag to keep the fabric from "blinding," an air-handling term for being clogged by fine dust. You can also reduce dust cake by blowing on the outside of the bag with compressed air. Before shaking or blowing bags that reside inside your shop, vacuum their outside surfaces to remove dust that's settled on them or has been attracted by static electricity. Vacuuming prevents bag shaking from raising an obnoxious dust cloud.
Most shop vacuums and many contemporary collectors are fitted with canister filters that employ a pleated paper-like filter media. Portable models that use one or two large-diameter canisters, such as the JET DC1100VX-CK, typically include a built-in cleaning mechanism. This usually consists of two or more brushes or rubber flaps inside the cylindrical filter, driven by a hand crank on top. Turning the handles causes the brushes/flaps to rub against the inside pleats, thus dislodging dust caked on the filter media. The flaps also release a certain amount of sawdust and chips that have built up between the pleats. In lieu of a built-in mechanism, you can also clean these filters with compressed air; just don't use too much pressure, or hold the blowgun nozzle too close to the pleats, lest you blow a hole through the filter media. It's very important to clean pleated filters regularly, say, once every other day that you work in the shop. If you wait too long between cleanings, sawdust tends to get packed between the pleats to the point that the mechanisms or compressed air can't clear them out. If this happens, you'll have to remove the filter canister from the collector and extract the trapped sawdust with a shop vacuum. A brush accessory fitted to the end of the hose can really help work the dust out of the pleats as you vacuum.
Filter cleaning is also a good time to check for rips or tears. Small rips or runs in fabric bags can be sewn up or patched. Larger tears in thin fabric bags can often be mended with an iron-on patch, the kind sold at fabric stores for repairing holes in jeans. Smaller torn areas of pleated filters can be fixed by gluing the paper-like material together with white or yellow glue. To fix a hole or larger tear (at least temporarily), clean the surface around the damaged area on the inside of the canister, then cover it with duct tape. Use a popsicle stick (or other short, smooth stick) to help press the tape down into the pleat.
If the bag(s) or canister(s) on your dust collector have been in service for several years or more, and you notice that sawdust collection from your machines just isn't as good as it used to be and doesn't improve after a thorough bag/canister cleaning, it's likely that your only recourse is to replace the filters. It's worth considering retrofitting plain woven fabric filter bags with either industrially rated felted material bags or canister filters, as these offer better fine-dust-trapping performance.
Check the Fan
If you have a single-stage dust collector where dust and chips pass directly through the fan before being deposited in a bin or bag, it's important to check the fan occasionally for damage. Early portable collectors and "economy" models were often fitted with plastic-bladed fans that are very prone to damage from impact with larger chips, screws and nails or small cutoffs. Even the metal-bladed fans found on better qualitycollectors may be damaged from contact with larger debris that's occasionally sucked up accidentally.
To check out your collector's fan, unplug the collector, then remove any ductwork or fittings that are attached to the flange on the intake side of the fan.There's usually a large enough opening to allow viewing the bladed fan inside; if it's not, unscrew and remove the fan's intake shroud. Use a flashlight, if necessary, and carefully inspect the entire surface of the fan. Make sure that none of the fan's blades have been cracked or broken. Metal blades fabricated from sheet steel that are bent can usually be straightened out, but a damaged fan made from cast plastic or aluminum will need to be replaced.
Clean out Switches and Electrical Boxes
Fine dust, by its nature, seems to creep into everything in a woodshop, and electrical junction and/or switch boxes on a dust collector are especially vulnerable. It's important to occasionally clean these receptacles out, as dust can not only foul switch and fuse contacts and relays, but could even cause a fire. Remove the box's and/or switches cover plate and use your shop vacuum to suck the inside clean. Fitting a crevice tool to the end of your vac's hose can help in concentrating suction to get dust from inside deep recesses.You can also use the vacuum to remove dust buildup from the outside and vented area of the collector's motor.
If you've experienced any switching problems with your dust collector-the switch doesn't always work, or power comes on intermittently-try spraying electrical components with a spray contact cleaner. These cleaners come in pressurized cans fitted with a narrow nozzle tube that makes it easier to direct the spray into the small openings of sealed switches and relays. Many contact cleaners do contain noxious, flammable solvents, so make sure to work in a safe, well-ventilated area and let the spray evaporate fully before closing the electrical box back up or operating the collector.
Check for Leaks
If you've ever used a shop vacuum that has a hole in its hose, you know that an air leak can compromise suction power. It pays to occasionally check your dust system's hoses, ducts, and fittings to make sure they're not letting in air. On portable collectors, start by examining the hose that connects between the fan and the collection housing. Even just the friction of the copious amounts of sawdust and debris moving through this hose can eventually wear it through. Inspect all your machine hookup hoses, and patch or replace them if you find holes or tears. Also check to make sure that the hose clamps that secure hoses to fittings
are snug and tight.If your system has installed ductwork, eyeball each metal (or plastic) pipe connection, looking for breaks or areas where the tape or caulk seal has cracked, dried or fallen away. Patch and reseal these areas as necessary, or re-wrap them with duct tape. Finally, inspect any gaskets or seals installed between the various collector components: The fan and intake shroud, the cyclone and fan assembly, the dust bin and its top cover, etc. Replace any gaskets that are cracked or missing sections. In lieu of factory replacement parts, adhesive-backed rubber weatherstripping (available in home centers and hardware stores in a variety of different widths and thicknesses) can serve as an effective gasket replacement material.
Sandor Nagyszalanczy is a furniture designer/craftsman, writer/photographer and contributing editor to Woodworker's Journal. His books are available at: Amazon.com