As a modeller of over 40 years experience I’ve done it all - except vacuform canopies. I’m working on the 1/48 Hasegawa Hurricane Mk1 and discovered to my surprise and horror that the canopy is one-piece and therefore can’t be posed in the open position. I got hold of a vacuform canopy but what next?
Does one cut it off the backing sheet with a scissors or sharp blade?
Can it be dipped in Future/Johnson’s Klear?
Which glue to fix it in position?[:S]
Cut it with a fresh sharp blade. Run it along the bottom at a slight angle. After that, just run over some sanding paper lightly, after this it can be treated as any other canopy.
You can use a new # 11 blade, and keep scoring along the lines little by little until you cut through. Don’t try to cut through in one swipe with a blade. You can use a small modeling scissors, but this is tough to do along curved canopy frames. You can also use a dremel with a thin cut off wheel. Before you do any of this, stuff blue tak or silly putty inside the canopy to make it more rigid as you cut. I even leave it inside while I sand the cut edges, because sanding something so thin and flimsy doesn’t work so well. I don’t know why you’d want to dip it in future unless there is a defect in it. I’d do all this with an optivisor as well.
Glue for canopies is a harder topic than the first two questions. Almost all types we ordinarily use in the hobby have some drawbacks. Canopies can be glued with white glue or the similar cements formulated for gluing transparencies. Epoxy holds well- it is just a bother to mix, and it is fairly viscous and thus harder to apply without smudges or beads.
CA is certainly strong enough, but gives off vapors that can fog transparencies. I was told that a coat of future would fix this. I tried it and got the fog. I was then told, that is okay, you can dissolve the future with water/alcohol mix. Depending on how much access you have to inside, maybe you can, maybe you can’t.
Beauty of canopies is that you can glue them back on easily if they do come loose. Windows are a lot harder- if they break out and fall inside fuselage they can be very hard to retrieve and because of flanges on many of them, almost impossible to re-glue with the fuselage closed. So for windows I do always use epoxy.
Don- I have Zap 2 part epoxy that can be wiped away with rubbing alcohol before its dry, if you have any smuges or excess oozed out.
Nathan makes a very good point. It’s easy to crack the things if you are at all agressive when sanding, soI always fill them with clay.
I cut them out with scissors and then sand to fit, go slow and take time.
I like dipping them in future, because it makes it a lot easier to remove overspray or other added gunk. And I think it makes them look better.
I use Elmers, it can fill some gaps.
One thing great about Vac canopies its that they are pretty flexible, so they can be made to fit a little easier.
On the subject of your Hurri, try cutting the kit part up. You have nothing to lose, right? I usually have success with that.
Thanks for all the replies guys, some very good advice that I’m sure I’ll put to good use.
I’ve built Hase’s Hurri kit before, and after cutting the kit canopy, the sliding portion will not fit over the fuselage to be posed open. You are doomed to a Vac.
& if it goes wrong… just cover it with a tarp
The only thing that bothers me about future on canopies for “improved appearance” is when they are used on very weathered aircraft. I know crews can “clean” canopies, but in spite of lots of elbow grease I have never been able to make a windshield or plexiglas windows take on a future shine.
Of course, now, with future available, I would be tempted to use it on full-scale aircraft 
But, back in the day, future was not available and plexiglas cleaners and polishers did make some improvement but especially UV exposed stuff still looked foggy after polishing.