I'm making my next projector as small as possible, so I need to cut my FS mirrors perfectly to size, not just in the precut sizes.

So how do I cut my mirrors? I don't think they're tempered, so there's some way to cut them right?

On the other hand, is there anywhere I can get FS mirrors cut to my sizes?

Very good quality mirrors may be had from http://www.highreflectivemirrors.com/

This place was recommended by another mod whose opinion I highly regard. I likely will replace my current FS mirror with one from this place someday.

Peeps have cut them with a standard hardware store glass cutter with good results. Just keep it clean and be careful.

Any glass place would prolly cut for you at a minimal fee.

Just remember that a FS mirror has absolutely no protection of its reflective surface. Be very careful handling it and you should be alright.

Any ideas as how to do it yourself without taking it to a glass cutters?

Um. Go to Home Depot. Buy a glass cutter. Follow the instructions on the package. It should only cost a few dollars.

And practice.
with gloves & eye protection.

It took me more than a few try's to get a feel for it.
You don't have to press that hard.
Just score the surface in a straight line.

not as easy as it sounds though.