Completed the build of the fin other than the tail light mount. The tricky bit was welding into place the tubing ribs at the base of the fin that provide the anchorage for the fin covering - thin walled tube and tight joints. The curves in the ribs made from the 3/8" channel have straightened somewhat at the braze points so I will build them back up to a perfect shape using some epoxy and micro-balloons prior to painting the frame and covering it. I need to work out a better way of maintaining the curve before starting into the horizontal stabiliser and elevators.. 
