Understanding the Differences Between Metal and Plastic Shims

When you’re aligning precast concrete panels, installing doors or levelling machinery, precision is key. Shims provide that precision. But with different types available, how do you decide between metal shims and plastic packers or shims?

In this guide, we’ll break down the key differences, benefits and best uses of each option. Whether you’re managing a large industrial build or commercial fit-outs, choosing the right material can save time, money and rework.

What Are Shims Used For?

Shims fill gaps, provide spacing and maintain alignment in construction and engineering. They’re used in:

  • Tilt-up concrete panel installation
  • Window and door frame alignment
  • Equipment and machine levelling
  • Structural corrections
  • Precast and modular building setups

In short, they help everything sit exactly where it should, safely and securely.

Metal vs Plastic Shims

Metal Shims

Best for: Heavy-duty, high-precision or load-bearing applications

Typical Uses:

  • Machinery alignment
  • Automotive and aerospace components
  • Structural steelwork
  • Industrial equipment supports

Benefits:

  • High strength under load
  • Long-term dimensional stability
  • Can be precision-cut to suit exact tolerances
  • Resistant to deformation under pressure

Limitations:

  • Prone to corrosion if untreated
  • More effort required for on-site adjustment
  • Higher material and fabrication cost
  • Not as flexible for quick changes

On the metal side, we stock everything from 316 stainless steel shims to brass shim stock, each cut to the same tolerances.

Plastic Shims

Best for: General construction, residential and non-structural applications

Typical Uses:

  • Window and door installations
  • Cabinetry and furniture assembly
  • Light-duty levelling jobs
  • Precast construction projects

Benefits:

  • Lightweight and easy to handle
  • Resistant to water, rot and corrosion
  • Flexible, can be cut, stacked, drilled or nailed
  • Cost-effective and available in bulk
  • UV-stable plastic options available for long-term exposure

Limitations:

  • Not suitable for high-load or critical support points
    Can deform over time under sustained pressure
    Lower temperature and chemical resistance compared to metals

Need custom-made plastic shims? Call us on 02 4646 1166 for expert advice.

Which Shim is Right for the Job

There’s no one-size-fits-all solution. The right shim for your project depends on load requirements, environmental exposure (moisture or UV), precision needed, installation method and budget or timeframe. Plastic shims are often used for large volumes and faster installs, while metal shims are better suited to applications where strength and long-term durability is critical.

Why Choose PP Shim?

At PP Shim, we supply reliable shim solutions for commercial, civil and industrial use across Australia. Whether you’re working on precast panel installation, heavy equipment levelling or structural framing, our products are built to withstand tough site conditions.

Trusted by builders, engineers and contractors, our shims are manufactured to tight tolerances and high standards, with a wide range of sizes, thicknesses and materials. We also offer fast national delivery and bulk supply options.

Contact us today to speak with a shim specialist.

Metal & Plastic Shims FAQs

Are Plastic Shims Strong Enough for Commercial Jobs?

Yes, when used within their load capacity. PP Shim supply load-rated plastic shims that are widely used in commercial builds, especially for non-structural framing, glazing and fit-out work.

Some metals do, but PP Shim offer rust-resistant options such as stainless steel and treated brass. These are ideal for long-term, exposed or high-pressure applications.

No, it’s not recommended as the materials behave differently under load and temperature. We suggest using one type per application for consistent performance.

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Testimonials

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Kevin Miller profile picture
Kevin Miller
30 September 2025
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Excellent service by the team at pp shim! They supplied us with custom shims quickly and the quality was outstanding. Very professional team and easy to deal with. Would highly recommend for anyone looking for custom shims
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Alexander Chupranov profile picture
Alexander Chupranov
29 September 2025
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I have dealt with Peter to receive some custom made shims. Peter was easy to deal with and very helpful, i am very happy with the product and the assistance. Thank you so much for all your help.
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Josh Kearns profile picture
Josh Kearns
6 June 2016
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Great service and great response when i was in desperate need of a stainless shim kit. also came in a great pelican type harden case for added protection. Thanks Peter for your help.

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