tank bottom

The first step I took on this was to make a poster board template making sure to arch the poster board with the arch in the bottom of the tank. This was done to insure I had plenty of material to work with. I then transferred it to MDF and routed the edges with a quarter round bit. This was done to make sure once i started to roll the edges I would get a smooth roll. Once that edges were rolled over the form I had to create the arch in the tank bottom to match the tank. What I did was make small cuts in on the edges and then beat the arch into it with a rubber mallet.
Once I get the bottom welded in place I will start on the tunnel. Till then thanks for looking!