Hey! I'm building a cardboard sled. Any tips on materials i can use to make it fast? I can only use tape, cardboard, strings, and glue. Would it make it better to line the bottom with tape or some sort of epoxy to make it faster? anything would help
You could try taping a peice of glossy posterboard to the bottom to reduce friction and make it sort of waterproof? Make sure when you tape or glue it on that theres no seams where it can peel up at. Overlapping the tape over the surface might help. Cardboard and paper absorb water though, so it will only last a few runs.
cardboard itself it very fast on snow.

I made a cardboard snowboard (thee years ago) it was fun until I hurt myself. bad.
it only has to last 1 run downhill, but its on a ski slope so it has to last long enough (~30 SECONDS) downhill