I didnt use water at all. No problem. However the first panel I ever did I squeegied it on a little too thin, sorta like I was glassing. Had a few loose spots around the edge which were easily fixed. The next panels I put on just a very bit little thicker and all was ok. Just wipe off the excess after it squeezes out. It sands ok, just not as good as some have told me. I will always use this glue now for sheeting. Its great.
Edwin