When aluminium is the right call
Aluminium is a specialist choice, not a default. It earns its place where weight matters — long rooftop runs, suspended duct, and semi-rigid flexible aluminium duct — where corrosion resistance is needed but stainless would be over-specification, and in some marine and architectural work. Against the alternatives: galvanized is cheaper and stronger for ordinary air; stainless wins for harsh chloride or hygienic environments; aluminium wins on weight. See galvanized vs stainless vs aluminium for the full trade-off.
The 3003 alloy
Almost all HVAC aluminium duct is 3003-H14 — a manganese alloy chosen for its balance of formability and corrosion resistance. It spiral-winds and folds cleanly, takes a lock seam, and is the alloy behind both rigid spiral aluminium duct and the semi-rigid flexible aluminium duct used for connections. It is about one-third the weight of steel for the same volume, which is the whole point: lighter duct means lighter supports and easier handling on long runs.
Forming aluminium: what changes on the machine
Aluminium is fast to cut but softer to form: spring-back is noticeable and the TDF flange tolerance is tighter, so tooling clearances need adjusting. A machine rated for aluminium accounts for this; running it on a steel-only setup gives loose seams and out-of-tolerance flanges.
This is where Taokron machines differentiate. The SBTF-1602 and SBTF-2020 spiral tubeformers roll aluminium across their full galvanized range: 0.4–1.3 mm on the 1602 and 0.4–2.0 mm on the 2020. Many spiral machines cannot form aluminium this heavy. The lighter SBTF-1500 and 1500C are not rated for aluminium. So if you make heavy-gauge aluminium round duct, the machine choice narrows to the 1602 or 2020.
Gauge and weight in perspective
Aluminium uses its own gauge scale (Brown & Sharpe), but for duct it is simplest to specify in millimetres — 0.4–2.0 mm covers what Taokron spiral machines form (2.0 mm on the SBTF-2020 only). Per square metre, aluminium costs roughly 1.2× galvanized, but because it is so much lighter the installed weight (and the structure to carry it) drops. For the steel gauge-to-millimetre reference, see the gauge & thickness chart; for how aluminium duct is formed end to end, see how HVAC duct is made.
Rolling aluminium duct? Ask which SBTF model fits your gauge →
FAQ
When is aluminium used for HVAC duct?
Where weight matters (long/suspended runs, flexible duct), for mild corrosion where stainless is overkill, and some marine/architectural work. About 1/3 the weight of steel, naturally corrosion-resistant, but softer and dearer than galvanized.
How thick can aluminium duct be formed?
On Taokron machines, up to 2.0 mm — the SBTF-2020 forms aluminium 0.4–2.0 mm and the SBTF-1602 forms 0.4–1.3 mm, each matching its galvanized range. The SBTF-1500/1500C do not roll aluminium.
What aluminium alloy is used for ductwork?
3003-H14 is the standard HVAC duct aluminium — a manganese alloy with good formability and corrosion resistance. It spiral-winds and folds cleanly, takes a lock seam, and is the alloy most spiral aluminium duct and semi-rigid flexible aluminium duct is made from.
Is aluminium duct harder to form than steel?
It is fast to cut, but forming is softer: spring-back is noticeable and the TDF profile tolerance is tighter, so tooling clearances need adjustment. A machine rated for aluminium handles this; running aluminium on a machine set up only for steel gives loose seams and out-of-tolerance flanges.
