How to mount Aluminum to PVC?

I'd imagine 467/8 to be a fine solution, but what is the end goal here? If you are mounting 040 and 1/8 (3mm) pvc and then cutting out whole parts, then why not use an already finished product like omegabond or another ACM?

 

We use 3M 467 and typically join .040 brushed alum to 1/2" black PVC and it has always worked well with our Colex cutter. Both surfaces are smooth so the thinner 467 works fine, save a couple $$ as opposed to 468 but both will work well. I agree with Burton, if you can get away with 1/8" base material, use an off the shelf ACM. Unfortunately, customers seem to like the 1/2" base material and you can't get an AMC that thick.

 

I have wondered how to get them to lay flat with each other during the cure time. Would you need to add another large sheet with weights?

 

I was about to say this doesn't sound like the best idea.
If I remember right, 55420 is a very rapidly curing, something like 5-15 minutes working time, and you have to use the mixing nozzle and the $700 gun. Getting all of the glue out of the tube takes a couple of minutes, so by the time you're ready to mount the panel, it will have already started curing. Then you will have a hard time getting an even layer of glue, even if you laminated it back and forth I can't see this working well. You'd be better off with 3m Super 77 or whatever they use to mount formica countertops.
ASI is pretty cool stuff. I've had signs shipped in (one job in particular) where the fabricator quit halfway through a project, so a whole bunch of parts were glued together instead of welded. We use it to mount frames to thinner aluminum panels or prepainted materials.