The Similarly Stimulated Saturn

In making this Plexiglas (acrylic glass or acrylic) shield in front of the DC-DC I learned ways not to cut, trim, break, mold or work plexiglass. This is the same 1/4 inch material I used for panel (with 1/4" fiberglass). When cutting the plexiglass for the panel I used a Dewalt cut off saw with a standard 6 inch reciprocating blade while it was clamped and bolted to the fiberglass sheet. This worked out very well, actually the best of all the methods.

When making this small 6" by 3" shield and mount for the DC-DC Anderson disconnect I tried to score the piece on both sides then break it by bending the glass. The break was not good as you can see the broken piece on the floor. Next I tried to cut it with a spinning disk which just melts the plexiglass and is very hard to make a straight line. Plexiglass ShieldPlexiglass shield
So I FINALLY shaped the piece by; scoring both sides then clamping a piece of steel on both sides along the hoped for break line. It worked fairly well but there were some jagged edges. After the break I fine tuned ground the edges and rounded 2 of the corners.

Breaking Plexiglass Nov 15

So basically there is a better way and I do not know that way. Best from my limited experience is the reciprocating saw and being careful not to let the plate vibrate (by clamping to something).
Plexiglass will crack when you don't want it to. When drilled will also chip, especially if drilled quickly. If you drill too slow, the bit will heat up the acrylic and gum up.