I had a hard time getting the rear door/panel to be the proper shape, so I designed this set of jigs/frames to hold the various parts while putting it together. I print in ABS and acetone weld the parts together, so I printed the jig pieces in PETG so the door wouldn't accidentally end up welded to the jig. The jig is designed to maintain the proper curve as the door pieces are welded together and cured.
The Door Top Jig fits the top and bottom of the door (and can be used when assembling subsections, like the top panel, as pictured).
The Door Middle Jig fits the middle panel, as it has a center cutout in back for the recessed panel.
The Door Side Jigs help with aligning the side pieces as they are welded together, and have a slight curve to match the panel/door (in the picture you can see I'm also using one to hold the bottom of the door, as I was using two of the top pieces already on the top section of the door).
If, like me, you use a lot of acetone and there are ABS parts coated in it inside the PETG jig, you may have to use a butter knife to separate the jig from the ABS parts after the acetone has cured. An alternative would be to use acetone sparingly where the part will meet the jig and apply it there later on.
This is meant to work with the v2 R2-D2 as designed by the amazing Mr. Baddeley: