Welding acrylic is harder to do then siliconing a glass tank. Once you figure it out, it isn't that difficult. The most important part about welding is having a good properly prepared joint. Otherwise you will get air bubbles and leaks. The cure isn't instant. It will hold within a few minutes, and can hold water in a couple of hours, but continues to cure up to 24-48 hours. Because of the quick set time it is easier to move clamps and move onto other pieces when building a tank. Working with acrylic is almost as easy as working with wood, you use most of the same tools.