Alternative suggestion:
- save the page of a thread
- zip it
- upload the zip to a dedicated thread, with a description of the archived thread
Endchan starts autosaging at 500 posts, but the bump limit is 1000. I think max amount of files in a post is 5. So theoretically you could keep 500-5000 threads archived in a thread.
Media heavy threads, like bunch of webm/mp4s are different a bit...
Pls don't use imageboards as data storage facilities...