The lower tanks were sanded at the seams just enough to get rid of the rough ridge. They were then hand sanded with 150 grit sandpaper to allow the Caswell Tank Sealer to have good adhesion. Rubber stoppers of various sizes were used to temporarily seal the holes. The lower tanks were given a coat of sealer and the main tank was given a second coat after sanding the first coat of sealer. Once again, I noticed that there was about 1 hour working time with the Caswell product. The material was hardened in the mixing container at about 90 minutes after the intial mixing. This is also about the time I didn't have to worry about watching for drips/runs.
