Using the MDF from the spar building table, I built up two table halves to support the router and guide fences. I will use this these tables and fences when I cut out the groove in the spar for the wing attach plate. Using a couple of 2x4s screwed together to simulate the spar, I clamped the tables to the spar and the fences to the tables. I don't have the correct sized router bit yet but that was ok, this was just a test run. It's a good thing I'm experimenting on cheap 2x4s, as it didn't turn out as successfully as I wanted. I found the MDF fences that I'd made flexed more than I expected. Additionally, I had made the fences the length of the wing attach plate. This meant that the C-clamps that held it into place prevented the router from running the full length.
So lessons learned:
1. Use something stiffer for fence. - I'm going to use some aluminum angle.
2. The fences need to be longer. - 4 foot sections of aluminum angle should provide enough length. The router table is already 4 feet long.
3. The 2mm steps in the fence aren't all that effective when tracking with a large router. - Solution will be to set the fence at the narrowest width of plate, route the centre channel, then move the fence back 2 mm for the next width of routing.
Amateur built or experimental aircraft is about learning.