u/More_Wrongdoer4501

As you can see in the photos, this diaphragm is far from ideal. Each valve was set with its own small box before and was/is incredibly difficult to work with because they are so small.

I ideally would like a single larger box, but I cannot find one anywhere near the correct dimensions. My next thought was to build one out of some plywood and heavily waterproof it. Perhaps with epoxy or something. I’m sure it will eventually rot but I’m not sure what other options I really have without ripping it all out and making a new diaphragm.

My guess is that’s going to be the advice I get here but I wanted to check to see if there were any better ideas?

I need to span this gap with a butcher block. I have the same block ready to go. Just water-based Varathane topcoat.

My plan was to track saw on the existing blocks right past the box of the cabinet below, as far as I can, and finish with a handsaw/chisel at the end. Then add some biscuits and add a biscuit groove in the new piece all the way to the end so it slides in, finishing with glue, sand, Varathane.

Is this plan stupid? Is there any better options for retrofitting a block in here? What am I not thinking of?