I am looking to fabricate an acrylic/plexiglass bonnet with an open top and outside dimensions of 20" x 20" x 36" with 1/4" wall thickness. Essentially the bonnet pictured below, but with no top:
It seems easy enough by gluing two 20" x 36" pieces to two 19.5" x 36" pieces. But I don't understand how to get the really smooth and seamless-looking edges that are pictured here? Did they use a heat gun to do this? Or is there a particular type of adhesive or polishing process I need to use?