I’m noticing that lots of threads are questions about printing. phpBB is not the best tool for these kinds of discussions, because they tend to result in pages and pages of responses, very few of which actually contain useful information. When people later google for the same question, it’s almost impossible to find the useful answers in the huge haystack of responses.
I’m wondering if it wouldn’t be worth considering using something other than phpBB for this. Two options that come to mind are
A Stack Overflow clone; here are some options: https://stackoverflow.com/questions/32638/which-cms-or-other-framework-should-i-use-to-develop-a-stack-overflow-like-site
If you want to stick to something closer to phpBB, maybe Discourse would be an option. It offers things like badges, so useful answers could be marked, which will make it easier to find them for somebody looking through a thread: https://www.discourse.org/features