Lots to do with the HS much of which involves deburring, match drilling and deburring. This is the first time that it has been difficult to follow the plans as you need to do a lot of work before you can prime all the ribs, spars, skins etc. I fell foul of this with my initial enthusiasm to get going by riveting a doubler onto the forward spar before I had primed anything. Due to the amount of rivets I decided just to prime over it and it is Alclad to Alclad so theoretically should be fine. My only other mistake was a dent in the skin when my dimpler slipped out of the hole and the hammer went down before I realised it. With some advice from the UK builders group on Yahoo I flattened it out and it will receive some filler before painting – build on!