Following the success of the DIY Air Filter movement which is sweeping the US and Canada, the WHN Airborne Group DIY Filter Team has released 3 prototype designs using components available in the UK.
The filters are simple to make with the components being easy to source from online retailers. A non-exhaustive list of suitable components can be found here.
Video instructions for the box design:
Video instructions for the single panel design:
UK CR Boxes are constructed in much the same way as a standard Corsi-Rosenthal Box, the sole exception being that the fan must be housed inside a box to achieve a square shape.