Plexiglass knife handles

“The hot behavior of cast Polymethylmethacrylate (PMMA) is isotropic, with a maximum contraction of 2% in all directions; while the extruded product has variable contractions depending on the thickness and direction of extrusion.”

This sentence, which to many will seem cryptic, contains the motivation for Coltellerie Berti’s choice of a Polymethylmethacrylate for the production of the handles of its knives.

After a negative experience, we gave up the use of extruded materials, i.e. those obtained by injecting molten granules into molds at high temperatures: economical to work (more finished handles with each molding), they break irremediably when washed in the dishwasher because, when heated, has uncontrollable behavior.

We therefore chose cast PMMA, more expensive and difficult to work with, obtained by adding a cold catalyst to a syrupy, transparent and with a strong odor resin (polymethacrylate).

The resulting liquid can be dyed by incorporating a dye before the catalyst and the result obtained is a material that is stable over time which does not yellow, does not age and maintains its shine unaltered. Poured into a formwork, after plasticization (generation of long chains of macromolecules) it becomes a rigid, shiny slab with a slightly irregular thickness which can be worked and modeled by hand by removal according to the methods and shapes typical of the “Berti Method” used for traditional materials.

Finally, to control the inevitable shrinkage, Coltellerie Berti have invented an exclusive stabilization process that avoids breakage in the dishwasher.