Hey,
I'm going to cast a concrete slab for outdoor use. I've built the mold from 12mm form plywood and reinforced it with beams. I'm just done with the mold but notice that the plywood is a bit uneven at the edges. I used a whole 2500x1200 sheet and placed the mold edges on the outside of the sheet. Either I was inattentive when I checked the sheet before or the unevenness happened when I screwed the mold together. Maybe I tightened it a bit too much. These unevennesses are along both long sides more or less all the way.
Do you think it's possible to fix this? I'm thinking that I can either fill the mold before casting or just cast it as is, and if it turns out bad, maybe I can either sand the slab smooth or fill the slab with concrete? I'm not too confident about the last option...