The first thing we did was to tidy up the rather bad cuts I had made in the frame and then we set about fitting the new cross ply pieces. The reinforcement plan was simply to resin in fresh plywood at 90 degrees to the existing frame grain. The weakness being that the frame had too much flex and rode like a jelly.
The top tube line could have straight ply plank fitted so we opted Fort Worth pieces of 14mm ply glued straight in with a filament resin. The down tube is curved so we went for three layers of 8mm ply bent and glued with the same resin.
Before we went any further down the build we put all of the components onto the frame to see if it was even worth continuing.
The good news was that our plan had worked. The frame was now stiff and rode properly. We took it all apart again and glued in some wedges to aesthetically improve the joints then set about cutting back the excess material and shaping the frame.
Once all the gluing was finished we shaped the frame using an angle grinder with a sanding disc and then followed that with an electric sander. In all it was an afternoon of shaping and sanding.