Ok, I actually got started on today's escapades of the hole repair last night. This was another step I gave some careful thought to, because replicating the grain was important in getting the repair right.
I decided the ONLY way to get this right, would be to make a plug with the same grain on it to fill the void.
This meant I would now have to replicate the grain. By that I mean, I would need to make a mold of the grain with fiberglass resin, (a negative) and would use that to make an exact copy (a replica, or positive if you will) of the grain pattern.
I made a mold on the opposing side of the radio, as can be seen in the pics below. After the negative cured for a couple of hours, I used that to make the actual replica piece. The replica I allowed to cure overnight.
Side Bar: The plug idea I took from my woodworking hobby. Whenever I use fasteners to attach two pieces where the fastener hole may be visible, (for example, joining two kitchen cabinets together) I make a plug out of the same material I'm joining to make the fastening point virtually invisible. I figured, in theory, the same should work here.
I measured the hole, and it was just under 1/2". PERFECT for what I was wanting to try as I have a 1/2" bit and plug cutter. So I bored the hole in the dash to 1/2" and cut a wood plug as a test piece to check fitment. The wood plug fit tight, so I moved forward with making the fiberglass resin plug.
I cut a couple of plugs, and of the two, I picked the best matching to work with. Either would have worked, but I gave myself a choice, which allowed me to be picky.
I set the plug in place with a little fresh resin to bond it in and fill any voids around the pug. After it set up for a few hours, I did a little light sanding and removed any flashing around the plug with a pick, to make it blend as best I could with the surrounding grain.
When I was happy it looked ok, I shot it with a little black interior dye to see what the end result would look like. I have to admit, I'm pretty happy with how it came out. It sure beats that unsightly hole!