Plastic welding and fabrication

Fabricated thermoplastic equipment for chemical service — tanks, scrubber bodies, ducting and bunds in PP, PVDF and PVC.

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This page covers fabricated thermoplastic equipment. If you are looking for polyethylene pipeline jointing, that is on the HDPE pipe welding page — different machines, different standards, different work.

Fabrication is where plastics earn their place. In chemical service, a polypropylene or PVDF vessel outlasts a lined steel one and costs less to maintain, provided the welds are made correctly. That proviso is the whole job.

Materials and where each belongs

Polypropylene (PP) — general chemical service, tanks, bunds, ducting. Good chemical resistance at moderate temperature, easy to weld, economic.
PVDF — aggressive service, high purity and elevated temperature. Expensive, and specified when nothing cheaper will survive.
PVC and CPVC — cold chemical service and drainage. Solvent cemented or hot-gas welded depending on the application.
HDPE sheet — bunds, linings, launders and containment, where the sheet is welded rather than the pipe.

Welding methods

Extrusion welding

Molten filler is extruded into a prepared groove while the parent material is pre-heated. The method of choice for sheet-to-sheet joints in tanks, bunds and linings, where joint volume is substantial and strength matters.

Hot-gas welding

Heated gas softens parent and filler rod simultaneously. Used for thinner sections, ducting, corner welds and detail work where an extrusion gun cannot reach.

What we fabricate

Storage and dosing tanks, vertical and horizontal
Scrubber bodies and gas washing equipment
Ducting, hoods and fume extraction
Chemical bunds and secondary containment
Launders, weirs and open channels
Covers, gratings and walkways in chemical areas

Workshop or site: where access allows, equipment is fabricated in the workshop and delivered complete. Where it does not — a bund inside an existing building, a tank too large to transport — fabrication is done in place.

Standards we work to

DVS 2207-3
DVS 2207-11
DVS 2205
DVS 2201
SKZ DVGW GW 331
EN 13067

Common questions

What clients ask before awarding

What is the difference between this and your HDPE pipe welding?

HDPE pipe welding joins polyethylene pipe end to end with fusion machines, for pipelines. Thermoplastic fabrication builds equipment — tanks, ducting, bunds — from sheet and profile in PP, PVDF, PVC and HDPE, using extrusion and hot-gas welding. Different machines, different standards and usually different projects.

Which material should I specify?

It depends on the chemical, the concentration and the temperature. Polypropylene covers most general service, PVDF handles aggressive and high-temperature duty at higher cost, and PVC suits cold service. Send us the process conditions and we will recommend, with the manufacturer’s chemical resistance data attached.

Are your plastic welders qualified?

Work is supervised under the SKZ DVGW GW 331 certified-supervisor standard. Individual welder certificates are provided upon request.

Can you fabricate in place inside an operating plant?

Yes. Site fabrication is routine for us, subject to permit, hot work control and ventilation. Where the item can be transported, workshop fabrication is usually faster and better controlled.

Send us the drawings. We will tell you what it takes.

BOQ, isometrics, specifications or a full tender package. Acknowledged within one working day, with the machine schedule and programme in the offer.

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