The Development of a Fixed Polarizing Filter

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

That'll work -- and without sandwiching because the bandsaw blade moves in only one direction. I used a scroll saw for cutting the pieces shown in my photo, and I believe I managed without sandwiching even on that by careful choice of blade. The only catch is that blade teeth do leave a slightly rough edge, so one normally sands the edge after cutting to get a nice matte finish (which can be polished easily, if desired). You definitely need to sandwich it if the saw blade teeth are too coarse, otherwise you'll get a little chipping giving an uneven edge.

A couple of years ago, I tried cutting acrylic tube for a different project using the scroll saw... but that didn't work as well as using a standard pipe cutter, which is basically a variant of score & snap. The pipe cutter gave me an edge that didn't even need sanding.

Incidentally, the same choices work for cutting most plastic goods. The catch is that some plastics have a low enough melting point that a hot saw blade will partially melt the edge and can give a rather messy result. For example, the plastics commonly used to make lens and body caps do NOT cut cleanly, but get gooey when sawn or drilled.

A rough or gooey edge was no worry. I'd touch up the edges with a belt sander to remove burrs, and the edges and corners were hidden under the bezel after assembly.

Acrylic doesn't get gooey, so belt sander is serious overkill, but fine.

Sorry, I mean that's what I did.  There would be burrs and chips and uneven spots from the bandsaw, so I would touch up the edges on a belt sander lightly.  The bezel on a camera filter will be even more sensitive to flaws and particular about tolerances.