Cutting resin filters

[Paul O]

A bit of a daft question but ... has anyone tried trimming a resin (Lee) filter to a smaller size (I need a 76mm x 100mm size) and if so any tips as to best tool to use? Don't want to risk ruining a filter if someone has a tried and tested technique :D Thanks

[vinny]

I've cut lots of plexi and lexan using a standard utility knife. Cover the entire filter with masking or painters tape first to avoid scratches. Mark your cut with a fine point pen on both sides. Use a straight edge and gently score both sides. This'll keep from making jagged edges or cracks when you break off the excess. Use some wide pliers to break off the excess. File the edges smooth and peel off the tape. This is the safest method. A band saw with a guide would work well also.

[Paul O]

Excellent - many thanks!

[Tracy Storer]

I'll add that any power saw used should have a fine-tooth blade, small throat (tight clearance around the blade to ensure good support of the work-piece around the cut), and you should use a slow feed rate.
This based on work with acrylic and ABS. YMMV with polyester.