Today is primarily preparing the skins, longerons and bulkheads for priming. Because there have been questions on what materials I use, I will list them here.
The first process is scuffing. The best is to do this after deburring, but before dimpling. The dimples will wear your scuff pads down very quickly.
I use either Scotch-Brite Hand Pad 7447 or the Colad scuff pads. You can clearly see the difference between the scuffed aluminum and the unprocessed aluminum.
The reason to scuff up the aluminum is to make the primer stick better to it. Although I tried on practice parts to prime unprocessed alubinum and the result were also very good. However the consensus is that scuffing is better, so I’ll stick to that.
On many places the top skin overlaps over the side skin, so on these locations I remove the blue vinyl and scuff, degrease and prime these parts too.
I found a small strip on the tail side skin that also overlaps, hence I have to prepare that part also.
I use the KRISTAL Aqua degreaser 3000, to cleane up and degrease the aluminum after scuffing. I apply the degreaser with Colad (glue free) degreasing towels, while wearing Colad disposable nitrile gloves.
For priming I use the Sikkens (Akzo/Nobel) Washprimer 1K CF combined with the Sikkens Reducer (2 to 1 ratio). Although it’s just a single component etching primer, I’m really impressed by the results and the ease of spraying it.
Time: 3 Hours, Rivets: 0/0 (2019-11-27)
Time: 4 Hours, Rivets: 0/0 (2019-12-01)