Cutting rectangular glass filters?

Discussion in 'Accessories' started by trailguru, Feb 5, 2015.

  1. trailguru

    trailguru Mu-43 Regular

    Nov 9, 2012
    Somerset, England
    Does anyone know how to cut or trim down a rectangular glass filter?

    I'm aware that there are lots of ways to cut flat glass from using hot wire and a water plunge through to bonded diamond cutting wheels but I'd like to hear from someone who's done this before. Successfully of course!
  2. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Using a carbide or diamond scribe make a deep scratch on the line you want to break(if it's a wheel version some need oil), put it on a flat table and put something heavy ontop of it which runs the full length so that the scratch is hanging out over the edge of the table(scratch should be facing up) -> using pliers grip the end of the part you want to break off and pull down. If the glass isn't tempered the crack will start and follow the scratch all the way to the end, If it's tempered the entire sheet will shatter into little tiny pieces. You will then have very sharp edges which you can clean up using a diamond file.

    The better option is to take it to a good glaziers and have them cut it with a water jet cutter (or the correct jig setup to cut glass), it will cost a few dollars and take a minute or two with far less risk.

    I've only done it for float glass for something like a window which is pretty horrible for optical purposes as it isn't flat and causes distortions, if it's for something like conkin filters it may not even be glass (it may be an "optical resin").