I'm by no means good with acrylic but I just converted a 90g shallow tank and split it in half with acrylic to essentially have 7ft to travel length. After 4 sets of baffles I'm pretty comfortable using weldon now. However, I couldn't imagine trying to bond 2 4" tubes together and applying any type of pressure horizontally. The cuts would have to be perfect for it not to look ugly. Huevos grande, my friend.