I'm building a Featherweight fighting robot with my boy and he's had the idea that we suck ourselves to the arena floor to give us more grip on our wheels and harder to flip over (so proud of that idea). My job is to work out how do it!

We've done some testing with a donut ring made out of EVA foam (camping/yoga mat stuff) about 10cm round to act as suction cups but I need them to be able to slide around the floor so need to be quite slippy, soft enough to form a goodish seal for the suction and strong enough to withstand some abuse from opposing robots.

I'm leaning towards un-resined Kevlar fabric but which one? I guess it needs to drape over the foam ring yet not be such an open weave that it lets too much air in. Any ideas/suggestions?

Kevlar would give you the strength, but there aren't any weaves I know of that would be really slippery and also be airtight.  The woven nature of the cloth means air will easily go through it.  Being a woven cloth, it would also snag if dragged over anything raised or edges etc. You could try coating with a flexible resin but it would need to be laden with graphite to help slipperyness, but a lot of powder content may weaken the resin.  So it is a bit of a difficult one. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant