Unlike folding quadrants, pleating a fluted filter is not that easy and require some training or some patience. We propose an 8 steps method using symetry to improve the consistency of the pleats.
There are a few different methods to fold a filter paper disc into a funnel-ready quadrant.
We propose an easy 3 steps method bellow.
Why some manufacturers express the filter's permeability as pore size while other use retention? And what the difference between pore size and nominal pore size?
Have you ever tried to compare filter paper between brands? Found a few cross-reference tables only to find out they contradict each others? You might have wondered how come nobody came up with a standard to describe grades and make sens of this mess?
Both methods turn a flat filter paper disc into a conical shape fitting a standard 60° funnel so it can hold more solution and use gravity filtration more efficiently.
While a quadrant folded filter paper is a disk simply pre-folded in a quarter of a circle, a fluted filter paper has been pre-pleated to minimize the contact surface of the filter with the funnel, decreasing filtration time.