Ken's Sonex 1243

[Sonex1243]

Some more progress since the last post. In between flying, getting instrument current, glider tow pilot re-qualified and a short trip with the wife, I managed to get all the skins on and up-drilled. I'm now in the deburring stage with the wing skins completed. Decided to polish them before installing and will do that last as the rest of the wing box needs to be deburred and the forward skin will need to be dimpled after polishing. Then, hopefully, the instant gratification of re-assembly for riveting!

[Sonex1243]

Thanks Ken! If you want to polish, now is the time to do it. Much easier when the skin is backed up by a table for the initial F9 polishing.

Brian / Dave.
Did you guys just polish with grade F9 and then finish up the other grades after assembly? I will be polishing the skins before assembly and storing while deburring the rest of the wing and dimpling the leading edge, how long does the initial polish last?

[Bryan Cotton]

Ken,
I do 3 passes of F9 and one pass of C. The parts look pretty good after that. Most of the violence is in the F9 passes. That is why you want to do it on a table.

[Bryan Cotton]

I should have added that you could skip the C and do as much F9 as you were happy with. I have a heated hangar and some of my stuff still looks great after nearly 2 years. Sort of dusty but that should come off on the initial flight.

[Sonex1243]

Thanks Bryan! The winter is fast approaching and working in an unheated garage! I'll start with the three passes and see how long this learning curve will take after some practice on some scrap metal.

[Bryan Cotton]

I would not spend a lot of time on scrap. That is polish and time better spent on real parts. Adam and I watched Kerry's video once then went at it.
http://www.eaavideo.org/video.aspx?v=25190150001

[Sonex1243]

Thanks for the advice, I did see that video a while back, but, a refresher is in order. Perfect time to start, just finished deburring, scotch briting and cleaning all the skins before starting on the rest of the wing. All laying out on the table now!

[Sonex1243]

Three passes of F9 completed on the upper aft skin. Looks like it came out real good, can see the fine swirl marks in the surface, but, looks like a little "grain" is still visible in some areas. One thing I was unsure of is I did three passes on top of each other in each area across the entire skin and then cleaned it all up. Watching the video of Kerry doing it, he did two passes and then cleaned. I wonder if I am supposed to clean after every pass? What have you guys done?

[Bryan Cotton]

Ken,
Between passes of F9 I polish off the residue with a cloth. I use mineral spirits before I polish with C.

[Sonex1243]

Bryan, I had been doing it all wrong on the first two skins! Just finished the forward skin by wiping after passes as you suggested and it was like night and day compared to the others, plus, I realized I was making the classic mistake of using too much polish and loading the buffer pad up. Got it right finally and now the pad is unloaded.. Guess I will go back to the other skins and do another pass, correctly, before moving on to the single C pass. Thanks again for the help!