Generic and Custom Plastic Extrusions, Gaskets and Seals

PVC extruded plastic gasketThe G.James Glass and Aluminium Plastics department has been operating since 1995, and started out manufacturing just 2 products for in house use. Type and quantity of manufacturing has been growing steadily ever since. Commercial sale of products initiated 5 years ago, and now supports several industries.

G.James Extrusions

The industries that G.James manufactures PVC plastic extrusion for include – building and construction, automotive, commercial refrigeration, marine, shop front, internal fit outs and railways to name a few. They come in a range of colours and PVC types, from rigid, semi rigid and flexible, including nitrile or rubber modified and TPV (Thermo Plastic Vulcanite) or Santoprene equivalent (this has the same properties, characteristics and function, but without the Santoprene brand name) as well as Santoprene, if its specifically required. Co extrusions (extrusions made from two different materials) and bushfire (BAL) rated extruded gaskets are also available.

The G.James facilities are capable of large scale commercial production. The production lines can produce up to approximately 2000m of plastic extrusion an hour – depending on the size and shape of the profile. Products are designed up to 100mm in Circumscribing Circle Diameter (CCD). At peak times, it will use up to 40 ton of material a month – and that’s not at full capacity.

Extrusion design

After initial contact, the design process involves an in depth look at what is required – the use, appropriate material for the conditions – sun and weathering, heat and chemical exposure. Identifying potential issues and mitigating them, or troubleshooting issues that may have occurred previously. Assessing die design and making a more effective proposal are all looked at prior to signing off drawings for a die to be made. Die trials are run and the resulting profile measured up for quality assurance purposes before commercial runs begin.

This process can take up to a couple of months if there is a lot of design involved, but is usually less. Ordering plastic extrusion has a two week lead time, but standard runs or more urgent requests can be processed to cater to customer needs.


During the design process

Efforts are made to ensure the die design is as beneficial and cost effective to the customer as possible. For example, a recent job started out with a profile design from a customer that required considerably expensive tooling and production costs.  Working with the customer and making a few die modifications, these costs were brought down by 60% . No impact was had on the effectiveness of the extrusion.

As an initial saving, G.James can arrange to have the tooling price amortised into the production price per metre to offset the lump sum.

Use in situ

18 years of experience by the PVC extrusion manager, Jason Clarke, ensures personal service from someone who knows how to make it work. Trouble shooting feeding problems, stopping gaskets from “popping” out of position, gasket “wave” problems and better shape design are among other issues that are addressed.

Point of manufacture

A length from every roll of extruded plastic is tested to ensure a quality product. Measurements are taken and information is recorded and stored so it can be tracked back to when and how it was made. Materials that work into other G.James products are also trialled for a suitable fit on completion to ensure a whole of system customer service.

Back end quality control

G.James conduct investigations into existing scenarios that are having problems. Extrusion and glass checks, incorrect use and out dated design issues can be looked at to assess the cause of any issues. Advice is given on the findings, whether it is a change in plastics die design, or other members that are found to be out of tolerance.

Manufacturing Process

It’s a short but interesting manufacturing process. The material comes in pellet form that is control fed through a hopper into a spiralling screw or ram. The pellets are heated, mixed and compressed as they are fed through the spiralling screw, and finally forced through the die into its final shape. After the gasket is extruded, it is immediately cooled in chilled water, and then dried before being cut into designated lengths and boxed, or rolled onto a spool.

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All off cuts of plastic extrusion are recycled on site. They are shredded and prepared to go through the same hopper feed and production process. As a quality control issue, recycled material is only used on non-structural gaskets, such as fly screen splines.

Brisbane designed and made, supply is distributed Australia wide, with much of our standard range available off the shelf at any G.James branch. For more information on product and supply, call the PVC manager, Jason Clarke, on 0403 352 703 or 07 3815 4908. Keep up to date by looking up the PVC page on the G.James website.