You will walk around the tank with your fist nearly touching the wet cement and marking just outside of your fist with the marker. 

The lid (Tapa) is one fist larger than the tank. Also mark on top where the two sheets overlap for reference.

Once the aluminum is marked, carefully remove the sheet  and place upside down on the ground. With the tin snips from your work bucket, cut the pieces as marked to form a circle. 

You will need 2 pieces of board (reglas), 90 centimeters long (roughly 2x2) 8 nails (clavos) and 8 pieces of flipflops. Hammer the nails into the flip-flop pieces before hammering into the aluminum and the wood. 

This will keep the nails from ripping through the aluminum later on. Tom if he is close by will show you how to line the boards up before attaching the sheeting with the nails.

Second Outside Pass

7. The first pass of cement will need about 2 hours to dry, depending on how wet the mix was and how much sun there is. The sun helps the cement to dry (speeds up the chemical reaction).  The faster the first pass is put on the better. And the dryer the mix the better.

8. Mix the cement for the second pass. Same as before, 4 botes de arena, 1 bote de cemento, and a bote de agua. This mix will be just a little bit wetter than the first.  Still roughly 1 1/2 botes de agua but a little more generous. Second pass is made the same as the first (just a little thinner).

9. We make a collar of cement around the bottom of the tank after the second pass of cement. 

You will need to save out about 1/2 bucket of mixed cement mix to use around the tank base. 

Drop trowels full of cement around the base (carefully) and then smooth with your float to form an incline from the tank to the outside edge of the base. Your original base will no longer be visible.