{"id":82463,"date":"2026-03-02T04:07:06","date_gmt":"2026-03-02T04:07:06","guid":{"rendered":"https:\/\/raptorcoatings.com\/?p=82463"},"modified":"2026-03-02T04:10:52","modified_gmt":"2026-03-02T04:10:52","slug":"how-to-use-raptor-plastic-filler","status":"publish","type":"post","link":"https:\/\/raptorcoatings.com\/au\/how-to-use-raptor-plastic-filler\/","title":{"rendered":"How-To Use RAPTOR Plastic Filler"},"content":{"rendered":"

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Navigate this How-To Guide<\/span><\/h3>\n
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  1. \n
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    1. Where to use RAPTOR Plastic Filler?<\/a><\/li>\n
    2. Prepare Your Surface<\/a><\/li>\n
    3. Mixing RAPTOR Plastic Filler<\/a><\/li>\n
    4. Applying Your Filler<\/a><\/li>\n
    5. Curing & Sanding<\/a><\/li>\n
    6. Tips & Tricks<\/a><\/li>\n
    7. FAQs<\/a><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/div>
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      RAPTOR Plastic Filler is a flexible body filler engineered specifically to resist cracking over time and for use on automotive plastic and other rigid and flexible plastics. Designed for repairing scuffs, scratches and minor surface damage on bumpers, trims and other flexible plastic components.<\/p>\n

      Be sure to check out our How-To Guides on cleaning and sanding surfaces and ensure you are wearing the appropriate PPE before taking on any project. Take the time to read the RAPTOR Plastic Filler Technical Data Sheet prior to application, and feel free to reach out to our team should you have any questions.<\/p>\n<\/div>\n<\/div>

      Where Can RAPTOR Plastic Filler be Used?<\/span><\/h2>\n

      RAPTOR Plastic Filler is ideal for:<\/p>\n

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      • Repairing scuffs, scratches and minor damage on bumpers and trims<\/li>\n
      • Flexible plastic components exposed to vibration and movement<\/li>\n
      • Automotive plastic refinishing and restoration work<\/li>\n<\/ul>\n<\/div>
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        Step 1 – Prepare Your Surface\u00a0<\/span><\/h2>\n

        For a complete run down on preparing your surface ready for filler, check out our guides on How-To Clean a Surface and How-To Sand a Surface. Here\u2019s a quick rundown on the necessary steps before application:<\/p>\n

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        • Clean and degrease the repair area<\/li>\n
        • Remove loose coatings and surfaces, or unstable materials<\/li>\n
        • Sand the repair area (read the TDS for the correct grit for each substrate)<\/li>\n
        • Re-clean the surface to remove any sanding residue and contaminants<\/li>\n<\/ul>\n

          Proper preparation is critical to ensure optimal adhesion to plastic substrates.<\/p>\n<\/div>

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          Step 2 – Mixing RAPTOR Plastic Filler<\/span><\/h2>\n

          The first step is to find a suitable mixing surface, DO NOT mix on cardboard as it will absorb the solvents and resins from the filler. We suggest mixing on a non-porous mixing surface such as a stainless-steel board, wax paper, or ideally or ideally a U-POL Onion Board.<\/p>\n

          When it comes to mixing in your hardener you want to ensure you have the correct amount for your temperatures and conditions. Too much hardener and your filler will be difficult to work and will start to cure before you can apply it. Too little and you\u2019ll be waiting for it to cure.<\/p>\n

          The go to rule of thumb for is \u201ca pea to a golf ball\u201d. One pea-sized amount of hardener for every golf-ball-sized portion of filler.<\/p>\n

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          10\u00b0C<\/strong><\/p>\n<\/td>\n

          		20\u00b0C<\/strong><\/td>\n30\u00b0C<\/strong><\/td>\n<\/tr>\n
          Hardener Required<\/strong><\/td>\n3%<\/strong><\/td>\n2%<\/strong><\/td>\n\n

          1%<\/strong><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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          When mixing in your hardener, you want to work it in entirely. Take your applicator and form it into a \u201cC\u201d shape, place it perpendicular to your mixing board and use a figure-eight motion for approximately 30 seconds until colour is uniform. Press out your filler to ensure you cannot see the hardener, if you still see your hardener simply follow the same process and mix the filler again until it is all one, even colour.<\/p>\n

          Avoid folding your filler over on itself as it can cause air entrapment and pinholes in your final finish.<\/p>\n<\/div>

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          Step 3 – Applying Your Filler<\/span><\/h2>\n

          To apply RAPTOR Body Filler, use firm, even pressure, to press the filler into the repair. You want to apply an even, smooth coat, immediately after mixing, aiming for multiple thin coats as opposed to one thick coat. Ensure your repair has been thoroughly filled before attempting to smooth and level the surface.<\/p>\n

          For deep repairs, build your filler over multiple applications and curing processes. This will reduce entrapped air, sagging and filler not curing properly.<\/p>\n

          Application tips:<\/p>\n

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          • Apply in thin layers rather than one heavy coat<\/li>\n
          • Maximum fill depth: 1\u20132 mm<\/li>\n
          • Build deeper repairs in multiple applications<\/li>\n
          • Use steady. even pressure to reduce trapped air<\/li>\n<\/ul>\n<\/div>
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            Step 4 – Curing and Sanding<\/span><\/h2>\n

            Once cured and your repair is filled, it\u2019s time to sand your filler down and get ready for priming and coating. Sanding can be tackled in two different steps, an initial pass to remove the excess filler and to shape your final finish, then a second pass to ensure your finish is perfect and ready to coat.<\/p>\n

            Initial sanding:<\/strong> P120-P180 to shape the repair
            \nFinal sanding:<\/strong> P180-P240 to finish prior to priming<\/p>\n

            If your final finish shows signs of pinholes and minor imperfections, you can apply RAPTOR Finishing Glaze to finish the surface, we recommend this for the best results and achieving a professional finish.<\/p>\n

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            Here is a guide on when you can start sanding your RAPTOR Plastic Filler after application:<\/p>\n\n\n\n\n
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            10\u00b0C<\/strong><\/p>\n<\/td>\n

            		20\u00b0C<\/strong><\/td>\n30\u00b0C<\/strong><\/td>\n<\/tr>\n
            Sandable After<\/strong><\/td>\n30 mins<\/strong><\/td>\n30 mins<\/strong><\/td>\n\n

            30 mins<\/strong><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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            Pro Tips for Professional Results<\/span><\/h2>\n
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            • Add the correct amount of hardener to avoid bleeding and spot marking<\/li>\n
            • Always mix thoroughly, ensuring no hardener is visible<\/li>\n
            • Apply with an even, firm, pressing action to minimise pinholes<\/li>\n
            • Build deep repairs gradually in layers<\/li>\n
            • Apply RAPTOR Finishing Glaze for a professional quality finish<\/li>\n<\/ul>\n<\/div>
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              Frequently Asked Questions<\/span><\/h2>\n

              How much hardener do I need for RAPTOR Plastic Filler?
              \n<\/strong>The go to rule of thumb is \u201ca pea to a golf ball\u201d. One pea-sized amount of hardener for every golf-ball-sized portion of filler. Refer to the TDS for exact mixing ratios<\/p>\n

              How thick can RAPTOR Plastic Filler be applied?<\/strong>
              \nMaximum fill depth is 1\u20132 mm per layer.<\/p>\n

              How soon can RAPTOR Plastic Filler be sanded?<\/strong>
              \nUnder normal workshop conditions, it is ready to sand after approximately 30 minutes.<\/p>\n

              Is RAPTOR Plastic Filler flexible?<\/strong>
              \nYes. It remains permanently flexible to resist cracking on bumpers and other plastic components.<\/p>\n

              What causes pinholes in filler repairs?<\/strong><\/p>\n

              Pinholes are small, trapped air bubbles that appear as holes in your surface after sanding, they are commonly caused by incorrect mixing or not enough pressure during application.<\/p>\n<\/div>