Mirrors go with projectors just as much as lenses do, but typically are difficult to work with as they are fragile, sharp, and can be tricky to mount and position.
I came up with a pretty easy method of mounting positionable mirrors with projectors, after WAY too much trial and error. This method is for pretty small mirrors, depending on weight..but probably would only be good for mirrors up to 8″x8″.
1. Goop glue. Don’t use anything but this. Epoxy is so so, but a bit too brittle. Goop is the best, it has a bit of flexibility. Not rubber, but a bit more movement. Epoxy doesn’t have any, so if you bump it just right, often the whole thing will come apart in one pancake of epoxy.. (just get Goop, any hardware store).
2. helping hands from electronics store. The ‘Shack would be the worst place to get these, but they have them. best is your local surplus store.
3. Mirror. Often a good hardware store will sell mirror tiles in a box. They’re thin cheap mirrors, but no big deal if they break. And, optically they’re fine.
4. glass cutter – again, any hardware store
Depending on how many mirrors you’re thinking, you’ll want to get probably numerous helping hands. Although you can use the alligator clips that come with them to hold the mirror, its a bad idea…I tried this first, even adding some gaffers tape so the alligator would have something to grip to. also you then see the clip in the projections. Not so great. Much harder to position as well.
The helping hands joints (thumb screw elbow connectors)…they don’t need to be gripping a little mini ball like they come with..but can also grip a screw head. So one method is to glue a bolt and screw to the back of the mirror, and use the helping hands ball joint grabber to grip a screw head. You then need fewer helping hands, as they come with 4 (I think) joint connectors. So basically all you end up using from the helping hands is the joint connectors. I’ve tried finding these alone, but can’t source them.
The results you can get from a single projector with multiple mirrors is fantastic.