Using the edge of a table as a guide, cut the end of the shipping tube at a 30-degree angle.
Place the freshly cut end against a flat edge, we used a brick set perpendicular to the edge of the table. Leaving about two inches from the cut tube to the edge of the table; Again, use that edge to guide your saw. Cut all the way through the tube, creating your first cylinder shape.
Mark where you need the final cut, start by matching the first shape and making a mark with a pencil. Check this by making sure the short side is also about two inches.
Make your final cut by placing the steep cutting edge against your flat surface and lining up your mark with the edge of the table. Saw with the edge of the table as a guide all the way through the tube. You should now have two matching shapes.
Seal one side of the form with tape and a piece of cardboard. Repeat in the other form..
Mix the concrete according to the manufacturer's recommendations. Its consistency should be similar to the mass of lumps..
Prop the forms up so they stand upright in a bucket, make sure they stay upright and fairly level. Pour slowly and carefully into the concrete. You will need to gently shake and stir the mixture into the form as you go to remove any air bubbles and ensure a smooth finish. Gently scrape across the top of the form to finish and allow the concrete to cure.
When the concrete is dry, remove it from the forms. You may need to cut a slot in the tube in order to remove it.
Sand down any rough edges. If you're struggling to get a smooth surface, try slightly dampening the concrete.
Cut a piece of contact paper larger than your concrete. Use rocks to keep the corners down, then carefully peel off the backing. If your contact paper doesn't feel very sticky, spray it and the concrete with a light coat of adhesive.
Place the paper clip on top of the contact paper and firmly turn it to one side, trim along the short edge. Repeat on the other side of the bookend, move carefully and apply pressure to avoid bubbles, cut the paper to allow for a slight overlap.
Carefully cut off excess contact paper at the top and bottom of the bra.
Repeat steps 10-12 on the second bookend and hold your books in style!