Wings: Ribs. And other updates.

• Bought Napa 7220 self etching primer for the spar countersunk holes.
• Ordered the replacement J-stiffener.
• Ordered the two missing parts.
• Spoke to Scott at Van's about the spar issue.  He asked the guys who build the spars what they thought.  If I understood Scott correctly, the shavings occur when the rivet is placed in the hole.  If any gap between the rivet and spar exceeds 0.005", then it would be out of spec.  He suggested I use a feeler gauge to measure it.  After he explained to me what one of those was (I was thinking the round spark plug gap checker), I went to O'Reilly's to buy one.  There is no gap.

Whilst I wait for my replacement J-stiffener, I continued working on the ribs.  I decided to cease straightening the flanges until after I debur.  So, I spent 3 hours deburring today.  It was the first time using the Scotch-Brite wheel on the grinder, so there was a learning curve:  At first I was timid with the wheel and wasn't happy with the smoothness of the edges.  But after being more aggressive with it, I could really get a nice smooth edge.  For some edges I used the hand deburring tool since I couldn't get to all sides with the wheel.  But, I didn't do the edges that are along the weight-saving holes in the webbing.  I'm going to do those after I'm done with the outside edges. I also found that I needed to pad the tool rest on the grinder with some electrical tape since the rest was scuffing the ribs.  Finally, I placed a fan to blow on the grinder to keep it cool.

 

Deburring edges.

Left:  The corner (the outside of the wheel is obviously not effective).
Right:  The pile on the left has their outside edges deburred (3 hours!).  The pile on the right doesn't.  Then I have to go through them all once more for the middle holes.