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.