While working on a sailboat project, I laminated two pieces to make the rudder. I thought that I had enough clamps to hold it tightly together but after the epoxy had set up, I noticed that the edges had a gap. Spring clams just do not cut it.
To fill the gap, I set the edge up level and clamped the part to hold it . Then I made a small dam about 1/8″ high for each end out of folded masking tape. Finally, I put a masking tape fence along each side of the edge. I mixed up 1 pump (about 1 ounce) of epoxy and poured it in between the fences. It flowed into the gap a bubbles began to come up. To speed the process, I pinched the sides of the gap with pliers to squeeze the air out, releasing sucked the epoxy in. Repeat as desired.
When the gap was filled with epoxy, I put C-clamps (G-clamps in some parts of the world) on wherever I could see that it squeezed the gap closed. This caused the excess to squeeze out but the fences and the dams kept the excess from flowing down the sides. (The drip you see in the picture is from the other edge before I learned the part about the dams at the ends.) When the epoxy was set, removed the clamps and tape. Sand the excess hardened epoxy off. The gap is filled.