Welded Plastic Assemblies | PP, HDPE & PVC Fabrication

Plastic welding is the process of joining thermoplastic sheets, profiles, and fittings by applying heat to soften the material and fusing the parts together under pressure. The result is a permanent, leak-proof bond that retains the chemical resistance and mechanical properties of the parent material. It is the go-to joining method for fabricating tanks, ducting, bund linings, and custom enclosures from industrial-grade plastics.

Our plastic welding service covers the most commonly welded engineering plastics, including polypropylene (PP), high-density polyethylene (HDPE), and PVC. These materials are chosen for their chemical resistance, durability, and weldability, making them staples of the water treatment, mining, chemical processing, and food manufacturing industries across Australia.

Hot-air welding is the most versatile technique. A stream of heated air is directed at the joint area while a filler rod of the same material is fed into the seam. The heat softens both the base material and the filler, and they fuse together as they cool. Hot-air welding is well suited to thinner sheets (typically 2mm to 6mm), smaller assemblies, and repair work where access is limited.

Extrusion welding is the heavy-duty option. A handheld or bench-mounted extruder melts filler material through a heated screw and deposits a continuous bead of molten plastic directly into the joint. This produces a thicker, stronger weld in a single pass, making it far more efficient for long seams and thick sections (6mm and above). Extrusion welding is the standard method for fabricating large tanks, vessels, and structural ducting.

Both techniques require skilled operators and proper preparation. Joint surfaces must be cleaned, trimmed, and bevelled to ensure full penetration and a strong bond. Our fabricators follow established welding procedures and all joints are visually inspected for quality. Pressure testing and spark testing are available on request for critical containment applications.

Polypropylene is the workhorse of plastic welding. It offers outstanding chemical resistance to acids, alkalis, and solvents, welds cleanly, and is lightweight yet tough. PP is commonly used for chemical storage tanks, fume scrubbers, plating tanks, laboratory bench linings, and ducting for corrosive fume extraction. Our polypropylene sheet is available in natural (translucent white) and grey, in thicknesses from 2mm to 30mm.

HDPE (high-density polyethylene) is another excellent welding material. It is tougher than PP, has superior impact resistance, and performs well in outdoor environments without UV degradation. HDPE is the standard for water tanks, bund linings, chute liners, and playground equipment. HDPE sheet is stocked in black, natural, and other colours.

PVC (polyvinyl chloride) is widely used for ducting, pipe systems, and enclosures where rigidity, flame resistance, and chemical resistance are needed. PVC welds at a lower temperature than PP or HDPE and requires careful technique to avoid degradation, but in skilled hands it produces strong, reliable joints. We stock PVC sheet in grey and clear for fabrication projects.

Welded plastic fabrications are found across nearly every industrial sector in Australia. Chemical storage tanks and secondary containment bunds are among the most common applications. PP and HDPE tanks safely store aggressive chemicals that would corrode stainless steel, making them essential in chemical supply, water treatment, and mining operations.

Fume extraction ducting is another major application. Welded PP and PVC ducting systems transport corrosive fumes, vapours, and moist air away from process areas in laboratories, plating shops, and manufacturing plants. Plastic ducting is lighter than metal, will not rust, and resists attack from the very chemicals it carries.

Other common welded assemblies include drip trays, machine guards, wash-down troughs, aquaculture tanks, electroplating jigs, and custom enclosures for electrical and instrumentation equipment. Wherever you need a corrosion-proof, leak-proof fabrication that outlasts metal in harsh conditions, welded thermoplastic is worth considering.

Perspex Online fabricates welded PP, HDPE, and PVC assemblies at our Gold Coast workshop and ships Australia-wide. Whether you need a simple welded tray or a fully engineered tank system, our custom fabrication team can work from your drawings or help develop a solution to suit your requirements.

Get a quote for your welded fabrication project by contacting us with your drawings, material preferences, and quantities. If you need sheet material for your own welding work, browse our range of PP, HDPE, and PVC sheets with cut-to-size available on all orders. All prices are shown ex GST.