
Why is the airtight seal important?
It all has to do with how gases and water vapour behave in enclosed spaces, and is governed by a few Laws of Physics, such as Boyle’s, Charles’, Dalton’s & Henry’s. In essence, once water enters a space (because it is not sealed properly) instead of the water evaporating out again later, it becomes water vapour and remains in the space for a much longer time.
In a climate such as the UK’s, this means the screw-head is continually in water & oxygen environment, never getting to dry out properly. This can cause the fastener to corrode (rust) up to 20 times faster than if a cap had NOT been used!
This effect can be easily confirmed, by examining vehicles that use hinge-caps over the number-plate fixings. Even on cars less than 6 months old, zinc-coated screws will show signs of advanced corrosion.
Similar issues arise with ‘polytop’ style plastic-coated screws. Often the plastic coating will crack as the screw is being tightened into place. Water can enter these cracks and cause accelerated corrosion, resulting in visible rust streaks.

Uses & Applications
Because they are UV-stabilised and completely seal the head of the fixing, Snap-Caps are ideal for exterior as well as interior applications. Even in extreme environments, Snap-Caps can be expected to last for 10-15 years, all the while protecting the screwhead against corrosion.
Snap-Caps are used in the following industries:
- Aluminium frames (showerscreens, windows, doors and wardrobes)
- Shopfitters
- Caravans, mobile homes & transportable homes
- Boats (from small runabouts to Navy frigates, high-speed ferries and ocean liners)
- Signs
- Vehicle number plates – specific colours are available to match UK front and rear plates
- Cabinetry (concealing all types of fixings, incl. the screws used with door handles and knobs)
- Furniture upholstery
- White goods
- Electrical and signalling control boxes and panels (Snap-Caps are an excellent way to insulate fasteners)
- Other vehicle applications – buses, trains etc, Horse floats and other trailers
- Aircraft – private and corporate aircraft up to BA 777’s and Airbuses
- Aftermarket decoration of motorcycles, SUV’s, lorries and HGV cabs