Looking for a RAS Ductseamer or DuctZipper? WNS does not manufacture new RAS machines — but with over 45 years' experience sourcing, reconditioning and servicing them, we are one of the most trusted names in the UK for used and reconditioned RAS duct seaming equipment. This guide walks through how RAS Ductseamers and DuctZippers work, the difference between V-form and L-form machines, and how to keep an existing machine running with quality parts, guide fences and AutoPilot Pilot Guide Carriages.
What is a RAS Ductseamer or DuctZipper?
A RAS Ductseamer or DuctZipper is a dedicated duct seaming machine that produces longitudinal seams along the edges of square or rectangular cross-section ducts. Traditional methods rollform a receiver lock, rollform a flange, then connect the two and close the seam — three separate steps. RAS technology takes all three down to one: insert the material, run it through, and the machine forms and closes the seam in a single smooth pass, giving a clean joint, extremely tight ducts and fast throughput.
Ductseamer is the name for RAS's standard duct seaming machine (models 22.81 & 22.82), while DuctZipper is RAS's automated line (models 20.10 & 20.12) built to work with the AutoPilot material handling system for higher throughput. Both use rows of seaming rollers — 15 roller shafts fitted with seaming rollers plus nine intermediate rollers in an overhead seaming bar — and are simple, reliable machines that can be operated by one person.
How a DuctZipper forms a duct seam
The in-line design moves through the machine along with the duct work, giving the operator the best access when inserting the sheet while the machine supports the duct as it forms and closes the seam.
The AutoPilot automates the duct seaming process with minimal operator involvement. Combined with the support arms of the material guidance system, it moves with the material in tandem through the machine — where previously two operators were needed, a single operator can now complete the work. To finish a duct with multiple seams, the operator simply puts the semi-finished duct cross-wise onto the guidance system and slides it back to the entry point.
The RAS SealJet injects an exact amount of Mez-Bluemastic gel sealant into the base of the seam just before the DuctZipper's forming rolls close it, sealing the joint without any sealant being squeezed out — leaving both the duct and the machine clean.
DuctZipper V-form vs L-form — what's the difference?
A V-form DuctZipper holds the duct edges in a V-shaped position so sheets slide by gravity to the connection point — a simple, workshop-friendly setup that suits small and medium-sized air ducts.
On the L-form DuctZipper the working position is rotated by 45 degrees: the horizontal flange of the duct rests on the table while the vertical flange points straight up, and gripping grooves in the vertical wall let the operator easily hold and guide the duct through the machine. This is specifically designed for large ducts — forming rolls stay easily accessible for maintenance, seaming accuracy is improved with less distortion of the duct cross-section, and with the AutoPilot clamping the next duct as soon as the first is removed, operating speed doubles. Even very large ducts can be produced with only two operators.
In the WNS range this shows up as the RAS Ductseamer 22.81 & 22.82 and DuctZipper 20.10 & 20.12 (V-form), and the DuctZipper 20.10-L & 20.12-L (L-form) for larger duct sizes.
The history of RAS duct seaming machines
Duct seams were traditionally formed and closed in separate rollforming and closing operations. RAS engineering combined these steps into dedicated Ductseamer and DuctZipper machines, then added AutoPilot material handling to automate the process further — technology WNS has spent over 45 years sourcing, reconditioning and keeping running in UK workshops.
What the manufacturers' literature said
Sales brochures from RAS and Firmac describe the same duct seaming process in their own words.
The RAS duct seaming range at WNS
From standard Ductseamers to automated DuctZippers and the accessories that keep them running, here's what WNS sources, reconditions and stocks. Each type below links straight into our live stock.
Used & reconditioned RAS machines
Applications & industries
Spare parts, service & machinery wanted
A RAS Ductseamer or DuctZipper is a serious investment, even second-hand. WNS has over 45 years' experience reconditioning, servicing and repairing RAS duct seaming machines, and stocks genuine forming rolls, roll shafts, replacement guide fences and AutoPilot Pilot Guide Carriages to keep an existing machine running.
Why choose W. Neal Services Ltd?
Buying a used machine is a long-term decision, so it pays to buy from a specialist who genuinely knows how to recondition and support it — not just resell it.
