How to replace foam gaskets on NiSi neutral density filters


When using any of the square neutral density filters in either the 70mm75mm100mm150mm or 180mm sizes the back side of the filter has a foam gasket that is designed to create a light seal against the filter holder. As you slide the filter in, the foam gasket ensures a complete seal against the filter holder and is designed to ensure that no light leakage can occur. This foam gasket can wear out over time as these filters are slid in and out of the holder. If not inserted properly there is a chance the gasket can also be damaged or potentially come off the filters themselves altogether.
Just like a car tyre needs to be replaced over time, the foam gasket on these filters may also need to be replaced as they either wear out, or gets damaged. The filter itself will outlast the foam gasket as long as it is not dropped, scratched or damaged in any other way. Replacing the foam gasket is quite a simple process, with sets of them available to be purchased for each individual sized filter here – NiSi Foam Gaskets (Spare Parts).
Follow the steps below for replacing the foam gaskets on NiSi ND filters and watch the embedded video to see how easy the process is for yourself.

Steps for replacing the foam gaskets on NiSi ND filters

  • Use a flat table and lay down a piece of newspaper or lens cloth underneath the filter.
  • Remove the old gasket from the ND filter completely.
  • Align the filter so that the printed name of the filter as at the top and facing down.
  • Ensure the back of the ND filter is completely clean of any dust, finger prints and remaining glue. We recommend using the NiSi Professional Cleaning Kit which includes the NiSi Liquid Cleaning Fluid and NiSi Microfibre Cloths. Spray liquid cleaner onto a microfibre cloth and thourougly wipe the filter clean using the cloth.
  • Once the filter is fully dry remove foam gaskets from the provided packet.
  • Line the filter up along one of the edges and ensure it you are placing with even spacing around the edge.
  • Partially remove the backing from the foam gasket so the sticky begins to be applied to the filter.
  • Gradually remove the remainder of the backing allowing the gasket to be applied and stick to the filter. Again ensure even spacing around the edge of the filter to allow it to slode into the filter holder correctly.
  • Once the gasket is fully attached ensure it is pressed down firmly all around the ND filter.
  • Clean the filter thorougly on both sides to ensure any finger prints and dust have been removed from the filter.

Replacing foam gaskets on NiSi ND filters video

2 thoughts on “How to replace foam gaskets on NiSi neutral density filters”

    • The foam is approx 0.75mm thick. The 150mm system does not require foam all around as the clips on the 150mm holder ensure no light leak on the two sides.


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