The large poly plastic water tanks are often found in the farm and agricultural industry. Many times, a poly storage tank will crack. This usually happens in the wintertime when the plastic gets brittle from the low temperatures. While the plastic water storage tank is brittle, the plastic may get kicked by an animal or bumped by a piece of farm equipment and crack and break. Luckily, these are easily repaired using plastic welders from Polyvance.
This particular cracked agricultural water tank had been sitting in the sun for many years and had developed a "crust" on the surface. The weld will not fuse with this "crust", so the crust was sanded away to get to some good "uncrusty" plastic.
Since we couldn't get inside the poly water storage tank, we had to do the entire repair from the outside.
We used a rotary tool with a teardrop shaped bit to grind a V-groove along the crack line.
This plastic water tank is relatively thick. To match the thickness of the original plastic, we had to melt in 3 passes (layers) of the polyethylene welding strip.