Acrylic sheets are popular for crafting and do-it-yourself projects such as fish tanks or display cases. Acrylic is easy to find and inexpensive. With a little work, acrylic panels provide a durable, useful box in only a few hours. Known sometimes by the brand names Plexiglass and Lexan, acrylic sheets can be purchased online or at any home improvement store. Some hobby and art supply stores also carry acrylic sheets and acrylic glues. Acrylic sheets come in many colours and thicknesses. For a fish tank or other waterproof box, you will need to purchase acrylic sheets at least 1/4-inch thick.
Purchase five acrylic sheets and have them cut to the correct size. Most sellers will cut acrylic for free or at a very low cost. You will need one bottom piece, two end pieces and two side pieces.
Gently sand the cut edges until smooth with a fine-grain sandpaper. Do not oversand these edges, You want them to be as smooth as possible. Wipe away any dust with a clean dry cloth.
Lay the bottom of the box on a flat surface and position one end perpendicular to it. Gently squeeze the acrylic glue onto the joint where the two meet being careful to keep the applicator in the joint and against the acrylic. Apply a thin bead along the joint. The acrylic glue will not simply adhere the two pieces, but it will actually melt them into one.
Hold the end in place for three to five minutes until the glue has begun to cure. Repeat this process with the other end, and both sides. Turn the box on its side, and add a bead of glue to the joints where the sides and ends meet.
The glue will begin to work in several minutes. Allow to fully cure overnight.
If your box is meant to hold water or another liquid, it is wise to waterproof the box by adding beads of clear silicon caulk to each joint.