Frequently asked questions

A machine that joins overlapping thermoplastic liner sheets into a continuous watertight seam. The main type is an automatic hot wedge welder, where a heated wedge melts the facing surfaces and driven rollers fuse them under pressure while the machine self-propels along the overlap. Hand extrusion welders and hot air guns cover the detail work a wedge welder cannot reach.

Hot wedge, extrusion and hot air. Each does a job the others cannot, which is why a crew equipped to finish a project carries all three. Full comparison in types of plastic welding machines.

No. MIG, TIG and MMA are electric arc processes for joining metal and have no application to thermoplastic liner. Plastic welding works by softening the material with heat and pressing the surfaces together, with no arc, flux or shielding gas. The machines are unrelated.

A hot air welder. PVC coated fabric, banner material, truck curtains and single ply roofing all weld with hot air rather than a wedge, at lower temperatures. For production volumes an automatic hot air machine is the right tool rather than a hand gun.

No, and this is the most expensive misunderstanding in the trade. A wedge welder must roll in a straight line, so it cannot weld around a pipe penetration, into a corner or over a patch. Crews that arrive with only a wedge welder reach the first penetration and stop.

The specification usually names the process explicitly, requiring dual track hot wedge welding on primary seams tested to ASTM D5820, with extrusion welding permitted only for patches and penetrations tested to ASTM D5641. Send us the clauses and we will confirm what you need before you order.

Whatever your destination uses. Machines are configured before dispatch for the mains voltage and plug type of the destination country. If the site runs on generators, tell us the rating, because an underpowered supply produces cold seams rather than an obvious fault.

Yes, four of them: the WGW 300 wedge welder, the booster EX2 and EX3 extruders, and the HT1600 hot air gun. Weldy is the Leister group value line. We supply them as a stockist, not as an authorised distributor, beside our own IZ machines. The Weldy range page compares the two.

Yes, held in Dubai. Heating elements, rollers, weld shoes, nozzles, carbon brushes and PTFE. Same day dispatch within the UAE and air freight overseas. See spare parts and accessories.

For hot wedge welding, roughly 330°C to 430°C depending on thickness, but temperature alone is not the answer because travel speed determines how long the heat is applied. Establish the pairing with a trial weld in the day's actual conditions. Starting figures by gauge are in the settings guide.

Dual track wedge seams are air pressure tested through their sealed channel to ASTM D5820. Extrusion seams and patches are vacuum box tested to ASTM D5641. Both are supplemented by destructive peel and shear coupons to ASTM D6392. See seam testing methods.

Usually insufficient preheat, so the extrudate landed on cold plastic and bonded mechanically rather than fusing. Other causes are an unprepared surface, travelling faster than the output supports, and the wrong rod resin.

No. Polypropylene and polyethylene do not fuse. A PP bead on HDPE looks completely normal, holds its shape, and separates cleanly the first time it is peel tested.

It is set by the design engineer against hydraulic head, subgrade, loading and chemical exposure. Broadly, 0.75 mm and 1.00 mm for farm ponds and water pans, 1.50 mm for landfill and canals, 2.00 mm and above for mining. Full properties by gauge are in the specification.

Yes, referenced to the roll numbers in your consignment. A CQA consultant will ask for them before accepting material onto site.

Interface friction on slopes. Smooth liner has a low friction angle against soil and geotextile, so cover material can slide. Texturing raises it substantially. Note that core thickness is measured differently on textured sheet, which catches buyers out.

Yes, to all six GCC states and across Africa, by road, sea or air depending on destination and urgency. Transit times by country are on the export page.

Commercial invoice, packing list, certificate of origin, and bill of lading or air waybill. Raise any additional requirements such as pre-shipment inspection at quotation stage, because several cannot be issued after dispatch.

Yes, and it usually makes sense. Liner fills a container while machines are small by comparison, so consolidating saves a freight charge and gives one set of customs documents.

Machines of this type generally fall under HS heading 8477, with 8477.80 the usual subheading, though some authorities classify hand held hot air tools under 8515. Classification rests with the destination authority, so confirm with your clearing agent. We state the code we use on the commercial invoice.