Here we are the glue has been cured over night. It is important the frame has been in a warm area to cure. Check your glue specs I like mine to be in the heated shop around 70 degrees Fahrenheit. I am ready to flush trim the excess from the outer layer. The trick here is I will now use the red inner core as my template.

The outer layer is now all flushed up with the red center layer. Again I used a speed controller to slow down my router to approximately 8000 rpm. This generates less heat and you router bit will last much longer Now I set the drill press to drill 3/16" deep into the outer layer. This is why I kept the pin holes cleaned out as much as possible in the earlier glue up step. It is very easy to get back in these holes and drill to the final depth in the outer layer. Drilling is done I cut my pins longer than I needed them and ground them down to the final length of just a tad under 5/8" The grinder leaves a burr on the end of the pins and I leave it on as a purchase for the epoxy to grab. I do a dry test fit and it all goes together easily. Ready to glue it up I use G-Flex epoxy for the glue up. I cove one side entirely and put some glue in the holes with a smaller drill bit as a tool to work the epoxy down in the holes. I also work the epoxy into the holes on the outer layer and put some extra in the middle which will cause some squeeze out. I also cover the pins in epoxy Now into the spring clamps. The use of to much pressure with clamps can be a bad thing as it can squeeze out to much glue. With a nice fit the spring clamps are more than adequate. Be aware and do not use excess clamp pressure. Their she lays for another overnight cure. As I mentioned make sure the cure area is warm enough for the epoxy you are using.
Now I am getting closer to the fun part. I always enjoy the final shaping the most