I’ve never used a 3d printer before but want to get one. I have a bit experience in blender but not too much. My question is: How do you model for a 3d print? For example, if I want to print a hollow cylinder, I go into blender, create cylinder and delete the side faces. If I print this, the walls will be pretty thin. Do I have to make them bigger manually? and if I do so (extrude and scale) does my slicer (cura) automatically fill in the solid part?
So it will ultimately come down to what file format you need for the 3D printer and if Blender can support that. Otherwise, you may need to generate your geometry using a CAD program.
Regardless, you will need to generate the solid model of your cylinder. In this case you’d extrude your cylinder surface to create a volume body and not a sheet or surface.
That is a weird take. File format is completely irrelevant here. 3D printers usually only accept G-code files, or something similar, which is unrelated to the file format used for the model. You can also easily convert pretty much anything to something your slicer will accept.