Often if one wants to make something "larger", dropping superglue, adding bicarb with a silt, blowing away and dropping another layer works fairly well (it's a bit of a brittle but still quite hard mass that is created quickly).
Then at some point I realized that I overdid it!
Easy-peasy, a file and sandpaper to the rescue, I thought.
Aand.. I spent x3 more time shaving off the excess than building it! It's super tough.
Also, your breath might help in a pinch (it's humid).
For comparison, there is a nice video by NileRed https://www.youtube.com/watch?v=phNLecfyWS8 He is making Bakelite that is a type of plastic. It's a tiny amount, in a lab, on purpose and he may make a few attempts. Anyway it overheat and instead of a nice piece of plastic he got a nasty block of foam with burned plastic. No imagine a huge tank of a similar chemistry reaction.