What's inside
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For a small workshop dust-collection system, metal duct is usually the better choice for permanent trunk lines, while PVC can be a workable budget option for a carefully planned, grounded installation. Neither material fixes an undersized collector or poor layout. Start by matching the duct diameter to the collector and the tools you’ll run; then weigh cost, static control, fittings, and installation effort.
Start with airflow, not pipe material
A dust collector needs enough air moving at the tool, and every foot of duct and every bend adds resistance. A 4-inch branch, for example, has much less cross-sectional area than a 6-inch line. Reducing a collector’s 6-inch inlet to 4 inches at the start can sharply restrict airflow, even if the pipe is smooth.
Check the collector’s manual for its recommended duct size and airflow requirements. Plan the main run with the fewest practical bends, use gradual changes in direction, and keep flex hose short. A long, corrugated hose can impose more resistance than a similar length of smooth pipe. If you have several machines, use blast gates to close branches you aren’t using; open gates on idle branches waste airflow.
Before buying fittings, sketch the route and count the wyes, elbows, reducers, and gates. For common workshop branches, 4- and 5-inch connections are typical, but the collector and tool ports—not a generic rule—should determine the sizes.
Metal duct vs. PVC at a glance
| Factor | Metal duct | PVC pipe |
|---|---|---|
| Upfront cost | Usually higher, especially for fittings | Often cheaper and widely available |
| Static control | Conductive when properly bonded and grounded | Insulating; grounding the pipe itself does not reliably remove static charge |
| Fittings and layout | Dust-collection fittings are available, but sizes and stock vary | Plumbing elbows and tees are easy to find but may have poor shapes for airflow |
| Durability | Resists impact and heat better; can dent | Can crack if struck and may soften or deform with heat |
| Best fit | Permanent trunk lines and higher-use systems | Budget-conscious, smaller systems where installation risks are managed |
Where metal duct earns its cost
Metal duct is a sensible default for a permanent system, particularly a main trunk that will serve multiple machines. Properly installed metal can be electrically bonded and grounded, and it generally tolerates shop bumps and warm conditions better than plastic. Purpose-made dust-collection fittings also make it easier to build a layout with wyes and sweeping bends rather than sharp plumbing turns.
Its drawbacks are real: duct and fittings can cost more, thin-wall sections can dent, and joints need attention. Use compatible clamps or screws as appropriate for the system, seal leaks with suitable duct sealant, and bond sections electrically where needed. Don’t assume that a metal pipe is grounded just because it touches another metal pipe; paint, gaskets, and loose joints can interrupt continuity.
Look for a metal dust-collection duct and fitting assortment if you’re comparing parts for a permanent layout. Verify actual diameters before ordering: duct sizes and tool ports are not always interchangeable.
When PVC is a reasonable budget choice
PVC pipe is inexpensive, smooth inside, easy to cut, and familiar to install. For a one-person shop with a compact system, a short run, and a limited budget, it may be an acceptable compromise. Use large-radius fittings where possible, avoid a string of tight 90-degree elbows, and support horizontal runs so they don’t sag or pull apart.
The key concern is static. PVC is insulating, so wrapping a wire around the outside does not turn the pipe into reliably grounded metal duct. Dust moving through an insulating pipe can build charge; a discharge may startle you, and dust fires and explosions are serious hazards. Fine wood dust suspended in air is combustible, though the actual risk depends on concentration, ignition sources, and system design. Do not treat a wire in or on PVC as a guarantee of protection.
PVC also has failure modes that matter in a shop: it can split after an impact, deform near a heater, and use plumbing fittings that create abrupt turns or obstruct airflow. Keep it away from hot surfaces and physical strike zones. Do not use it for compressed air; that is a different, much more dangerous application.
If choosing plastic, compare pipe and fittings intended for dust collection rather than assuming every plumbing part is a good airflow fitting. A PVC dust-collection pipe and fitting kit can help you price a small layout, but check dimensions and fitting geometry before committing.
Build for airflow and service access
Use a main line sized to the collector’s inlet, then branch down only where a tool connection requires it. Prefer wyes over square tees, and long-sweep elbows over tight elbows. Keep the collector’s inlet unobstructed, and avoid unnecessary reducers. A blast gate should close off an unused branch without leaving a leak around its slide.
Seal joints so the collector pulls air through the tool hood rather than through gaps. Leave access to gates and cleanout points; a plug of chips at a low spot can be difficult to clear if the duct is buried behind storage. Support long runs at regular intervals according to the pipe manufacturer’s guidance, and check that vibration from the collector or machines does not loosen connections.
For either material, wear eye and respiratory protection while cutting and deburring pipe. Collectors are not substitutes for a suitable fine-dust filter, and a shop vacuum or collector may not capture all airborne dust. Use tool guards and hoods, clean filters as directed, and avoid blowing settled dust into the air with compressed air.
Make the choice around your shop
Choose metal when the system will be permanent, heavily used, close to impact hazards, or shared by several machines. It costs more, but its durability and more reliable path to bonding make it easier to live with. Choose PVC only when the savings matter, the run is modest, the pipe can be protected from heat and knocks, and you understand that grounding plastic does not eliminate static risk.
If the budget is tight, a practical middle ground is metal for the main trunk and the most exposed sections, with short flexible connections at machines. Avoid mixing materials casually: use purpose-made transitions, maintain mechanical support, and keep the whole route accessible for inspection. Spend first on correct sizing and a clean layout; a cheaper pipe cannot compensate for a restrictive system.