On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M


When a hardware store cuts plexiglass for a storm door or window, they
put the sheet in a glass cutting frame. That is nothing more than a rack
with a straight edge and a lever to apply pressure against the part you
want cut. Then they use a special cutter made for plexiglass, which is
really just a sharp blade. They score it with that cutter from top to
bottom. Then they use that lever to apply pressure and SNAP, they make a
nice clean cut.

I was in a place where I had to cut some myself. I did not have that
special cutter or a rack. I marked it with a sharpie. Then I took a
straight piece of aluminum, laid it on my mark, and scored it with a
utility knife with a new blade. Once it was scored, I placed the scored
line along the edge of a board and applied pressure with my hand. That
worked fine.

One thing I learned, never try to drill plexiglass. You will end up with
small cracks around the hole. I once wanted to put some hinges onto
plexiglass and learned the hard way about the cracks. Then I used a
soldering iron and melted holes. It was kind of messy, sicne the melted
plastic builds up around the hole and needs to be quickly removed while
it's still hot and soft, but that did work in the end. (The soldering
iron tip was pretty much trash though, I ssaved it for future plexiglass
holes, but would never try to solder with it).