Thanks for your reply! The ball is closer to a meter I think
I will look into fiberglass now though, I just thought it was extremely expensive for some reason. Do you think the price would jump up a lot since the ball is that big?
I asked around a few other places and people told me I could make it pretty darn sturdy with lots of layers of paper mache, made with wallpaper paste rather than other types of adhesives. That route seems pretty cheap, but also quite time consuming (which is okay by me honestly).