Precision tubing for caravans: interior structure, opening and ventilation
The technical challenge of the caravan
Every kilo travels
The caravan and the motorhome penalise weight twice over: in fuel consumption and in available payload. The interior structure has to be light without ceasing to be strong. Saving weight by reducing wall thickness only works if the tubing keeps the formability to bend without cracking and the strength to withstand real use.
Vibration works everything loose
Unlike a home, the caravan travels: hours of continuous vibration that punish every joint, every mechanism, every bit of play. Tubing with a poorly calibrated diameter or a pronounced internal weld bead generates play, and that play, with vibration, turns into noise, wear and loosening.
Mechanisms used daily, far from the workshop
Doors, tailgates, windows, hatches, fold-down beds: mechanisms the user operates every day on holiday, where there is no service centre nearby. They have to work every time and not fail at the worst moment.
Interior on show and lived-in
The interior of a caravan is a living space: much of the tubing is on show and forms part of the finish of the cabin.
Applications where you will find us
Interior structure
- Lightness with strength Thin walls with the formability needed to bend the subframe without cracking or ovalisation, to lighten the assembly without compromising the structure.
- Surface ready for finishing When the tubing is on show in the cabin, the PREMIUM range provides the bright outer surface for direct chrome, zinc, brass plating or painting, with no prior polishing.
- Batch-to-batch consistency The diameter calibrated to a hundredth of a millimetre ensures every structure fits the same on the assembly line.
Opening mechanisms
- Shafts, pivots and guides without play With the OPTIM range we control outer diameter, bore and wall thickness simultaneously, with an internal weld bead ≤ 0.15 mm: the mechanism opens smoothly, without play and without the rattle that road vibration would amplify.
- Assisted-opening gas springs Tailgates and hatches held open by a gas strut: the PRECISE range provides the mirror bore to EN 10305-2 so the piston slides without leaks, as an alternative to seamless at 40% to 80% lower cost.
- Telescopic sections When two tubes slide one inside the other (support legs, extending elements), the fit between bore and outer diameter is everything.
Ventilation systems
- Low-pressure air conduction Tubing with a clean bore for the passage of air, in the small-diameter range where Delmàs works.
- Diameter and wall thickness made to measure, adjusted to the flow rate of each system.
- Non-circular profiles Square, oval or flat oval section to EN 10305-5, when the duct or the grille calls for it.
The right range for Caravans
OPTIMOpening mechanisms, shafts, pivots, guides and telescopic sections. Simultaneous control of bore and outer diameter, weld bead ≤ 0.15 mm
PREMIUMExposed interior structure and parts with a finish. Bright outer surface for electroplating or direct painting
PRECISEOpening gas springs and fluid/air conduction that demand a finished bore. Mirror bore. An alternative to seamless at 40% to 80% lower cost
Supply and service
- Coil supply or cut-to-lengthContinuous coil feed eliminates stoppages for bar changes and end-of-bar scrap on automated lines. Cut-to-length delivers the tubing at exactly the length specified in the drawing.
- Homologation and traceability with every deliveryCertificate EN 10204-2.2 (declaration of conformity with non-specific inspection results) or EN 10204-3.1 (inspection certificate with specific results for the batch supplied), conformity with EN 10305 / ASTM 513 / SAE, depending on what the manufacturer's quality system requires. In-house laboratory at the plant.
- Tubing transformed into a component ready to assembleWhen the customer needs it, we deliver the finished part —cut, bent, punched, end formed, machined— ready for the assembly line.
Why caravan manufacturers trust Delmàs
A family-owned business in La Roca del Vallès, specialising exclusively in small-diameter welded and calibrated steel tubing (⌀ 3–25 mm).
Thin walls with the formability needed for tight bends: the central technical trade-off of a structure that has to weigh little and withstand the road.
The diameter calibrated to a hundredth of a millimetre is what stops a mechanism from developing play and noise over the kilometres.
Manufacturing powered 100% by renewable energy since 2006, with two photovoltaic self-consumption installations at the plant.
Questions we hear every week
How do you lighten the interior structure of a caravan without losing strength?
With thin walls and the right formability to bend without cracking or ovalising. Reducing wall thickness without controlling the behaviour of the material is what causes cracking during bending. That balance is decided when the tubing is manufactured.
Why does an opening mechanism rattle over the kilometres?
Because of play amplified by vibration. If the tubing acting as shaft or guide retains a pronounced internal weld bead, or the diameter is not calibrated, play appears. The OPTIM range keeps the internal weld bead at ≤ 0.15 mm and calibrates the diameter to a hundredth of a millimetre.
Can you replace seamless tubing in a tailgate gas spring?
Yes. The PRECISE range offers a mirror-finish bore to EN 10305-2 and replaces seamless tubing in gas struts, at 40% to 80% lower cost and with predictable lead times.
Does the exposed interior tubing arrive ready for chrome plating or painting?
Yes. The PREMIUM range is manufactured with a bright, non-porous outer surface, suitable for direct chrome, zinc, brass plating or painting, with no prior polishing stage.
Do you manufacture non-standard sizes?
Yes, that is our speciality. If your mechanism needs 6.2 mm or 8.25 mm, we manufacture that size, controlled to a hundredth of a millimetre.
More subsectors in Automotive
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