Well, disasters sometimes happen. You just need to pick up the pieces and move on. After the first day of sealing the top of the left fuel tank, I entered the shop and noticed that the sealant that was used was not hardening. I am using the Semco tube system, and the process is somewhat new to me. I thought it would be impossible to mess up the ratio, but apparently, I did not inject the complete tube of hardener into the main tube....so my ratio was wrong. As a result, I elected to completely remove the skin and unhardened sealant. This meant I had to drill out all of the rivets in the upper surface spar. (There are a lot of rivets!) The only good news is that this mistake happened BEFORE setting all the pull rivets on the bottom surface. That would have been a true nightmare to remove. The skin was then dry fit, and the spar attach holes were enlarged to accept oversized NAS 1097 rivets. (This was done as a precaution since removal of the old rivets may have resulted in slightly oversized or irregular holes.) The skin was then recoated with sealant (I mixed the sealant manually on the scale this time) and the skin was reinstalled with oversize rivets in the spar. I have since talked to friends that have assured me that the sealant would have harded eventually....but this is a risk I was not willing to take.
