I inject hot melt glue into the central hole of each of the segments of rope light to help keep any water out and to reinforce the hot melt glue I add into the gap itself. Then I inject hot melt glue into the gap itself, being careful to ensure that both solder joints are well embedded in glue from all directions. Scrape off any excess glue that extends beyond the edges of the rope lights themselves. If you let it cool, you can cut the excess glue with an exacto knife. Careful, hot melt glue burns skin!