Cutting Ribs
After having tried several methods for cutting out the ribs, I have decided on the following method.
I block out the ribs 1/8" to 1/4 " larger than my mdf pattern by drawing around the pattern on the aluminum sheet with a permanent marker. I cut out the ribs and stack them about 5 to 8 deep under the mdf pattern, and clamp them to a board a little larger. Once they are clamped, I drill all holes, unclamp the ribs and deburr all holes. After I have all the holes drilled, I sandwich the ribs between the mdf pattern and some scrap mdf, with 1/4" bolts through the jig pin holes. I then trim the ribs to the edge of the pattern with my bandsaw. Next i sand the edges on the disk sander. If you are cutting nose ribs, this is the time to cut out the notches. Voula! Done and alike. The bandsaw is cheaper than the router method for me.

Finishing the rib edges.
The best and most efficient method of finishing the edges is to break down and buy a 6" 3m scotchbrite wheel in the first place. If you allow the rib to make a groove in the wheel, it will deburr all three edges simultaneously.

Aluminum Finish
A lot of builders are making their ribs so they look finished. Boy are they beutiful when done, and I am by no means cutting down the method. On the other hand if you are going to prime the ribs you will have to scuff the surface to give the primer something to adhere to. Instead of scotchbriteing them after fabrication, scuff them with a maroon pad while they are flat. You will have 100% of the surface scuffed, and the finish is satin. A side bennefit is that you will no longer cry when a scratch forms on the pretty shiny aluminum. Nuff said.

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