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Whatman paper filtration 101 – Part 3: Folding continue

Part 3 of this series describes various filter paper cone folding techniques. Read on to see the options for getting a good seal over your conical funnel.

Folding method Comments
Quadrant folded Fold the paper into exact quadrants.
Diagram of exact quadrant folding technique
(Diag 1)
Standard, very common technique
Quadrant folded Fold the paper into quadrants, then open to form a semicircle, identifying the center line.

Next, make two further folds, either in the same or opposite direction.

The result is a 60° cone when the paper is opened out.
Diagram of 60 degree cone quadrant folding technique
(Diag 2)

Allows the paper to filter in a more balanced manner than standard quadrant technique

Has certain disadvantages, especially if the precipitate tends to creep

Quadrant folded Fold the paper into quadrants.
Make an extra fold at a slight angle from the center.
The result is an angle at the apex of the cone slightly more than 60°.
Diagram of quadrant folding with angle at apex technique
(Diag 3)
Can provide a better fit when wet and loaded with precipitate
Quadrant folded Fold the paper into quadrants,
Tear off the corner of the outer fold
Diagram of quadrant folding with tear technique
(Diag 4)
Enables the rim of the filter paper cone to seal better against the glass funnel than a standard quadrant fold

Tearing the corner is better than cutting as it tends to stagger the two thicknesses of paper.

Pleated/Fluted paper Pleating

Fold the paper into exact quadrants.

Make a further two folds bringing the outer edges in two the center line.

Open the folded circle and invert.

Push alternate folds into the center, making a neatly pleated arrangement.
Diagram of pleated/fluted paper folding technique
(Diag 5)


Pleating filter papers is a very widely performed technique and offers improved flow characteristics compared to c

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