I think I've mentioned to a couple of people the glue I've started using on acrylic (including @sarahlouise and @wamonite who I happened to meet at the space this afternoon / evening).
This is the stuff - Revell Contacta Professional. It's a clear liquid that isn't really sticky, but softens the very surface layer of the plastic so that it fuses with other pieces, and seems to work nicely and makes for quite discrete joins.
Generally I clean the parts to be glued with a bit of IPA first to remove any finger grease etc.
There are a couple of things to be aware of...
It's almost like water so there's a slight art to applying it
Apparently it's flammable - so no using it in the laser cutter until it has completely and utterly dried (when it's probably safe, but I haven't tried yet, so proceed with caution)
It takes a fairly long time to dry and reach full hardness (if you can I'd give it 24hrs undisturbed)
It isn't a conventional glue so it will only work on some plastics
It isn't sticky so you'll need to make sure there's something holding the pieces together while it sets
If the metal applicator tube clogs apparently gentle warming will clear it.
Anyway that's the stuff, just thought I'd mention it in case it proves helpful to anyone.