I've tried tying Java Fern to a lava rock with thread but it was challenging and cumbersome. I just purchased a two-pack of Seachem Flourish Glue from Amazon for $7.19 and it's a total game changer! SO easy to use and it sets up in 20 seconds! One piece of advice: Use gloves or a Q-tip for application because it's hard to get off your hands!!
Is'nt the main ingredient Cyanoacrylate, aka super glue? I believe some vairants of super glue like Gorilla glue or Duro might be usable as well, and a lot cheaper. Aquarium glue probably gives peace of mind though.