Today, I began by researching Proseal. I then mixed up a small test batch and found the plastic bag method does not work well. I decided to use popsickle sticks to apply the proseal per Van's instructions. I went to Hobby Lobby and purchased popsickle sticks two sealing glass containers to mix and store the proseal in. I then attached the backplate for the end ribs and riveted the platenuts to the backplate. I sealed the rivets and moved on to the tank skins. The tank stiffeners were sealed in place and every hole was cleco'd. I left the assembly in this position to set and will rivet the stiffeners in place tomorrow.