Here’s the new transmission tunnel part – sides are mdc, and curved surfaces are body-filler. There’s an entire wooden frame in there keeping it all in shape.
I’m using some ultra sticky double sided tape to hold the side panels of the tub in place. You can see the stuff here. It’s incredible.
Here is the polypropylene plastic sheet forming the side of the tub mould. The tape gives me 0.7mm clearance between the sheet and the side, which is a good gap when I apply the epoxy adhesive to put the final tub in place. The adhesive has a maximum structural fill gap distance of 2mm so precision is called for.