I’m thinking of making something similar to these stackable shelves. But I want to do it using hand tools only so it seems plywood is out of the question (searching online said it would damage my Japanese hand saw). So I’m looking at solid wood instead and getting pine hobby boards that I won’t have to plane seems to be the easiest and cheapest alternative. The shelves will mostly hold records and books and the largest will probably be 30x30x75cm but stacked on other shelves. Am I in for a bad time?
I would say it would be fine, the only problem would be warping as the pine will be quite thin (plywood is more resistant to this).
But if you don’t care about everything being perfectly straight I think pine would be plenty strong enouph and wouldn’t warp noticeably much either (just pick straight boards from the store). So yea I think it would be fine.
P.s. (if you join multiple boards together its usually less likely to warp but I don’t think this is necessary for your usecase)