My trick for procuring cheap(ish) thick HDPE is to look for cutting boards at Ikea (or elsewhere, anything that is produced for the mass market)
I got this 3/4" one for [can’t remember exactly but it couldn’t have been more than $20 or I wouldn’t have bought it]:
Off topic but I can’t resist: this was the opportunity to see what happens when taking aggressive cuts in HDPE without dust collection. This is 5 minutes worth of cutting, I regret not capturing that on video, that was quite funny
A good 10 minutes of thorough vaccuuming (which must have generated even more static, I was in static hell by then!), then touching everything while cleaning-up must have been enough to discharge. I’m very fortunate to have a machine/setup that happens to not be sensitive to static (I have had maybe two disconnects in three years, and that’s without even caring about grounding everything…sheer luck, you might call it)
Are you positive? Not guilty as charged? (OK I’ll stop)
When I cut the unknown evil grey plastic on mine the grounding test was that it didn’t block the extract hose like it did on the table saw and that it wiped off easily without clinging, I’m not aware of anything that stops plastic chips initially sticking where they land.
My recent efforts are starting to highlight the importance of keeping the chips away from the rails and V Wheels if you want accuracy however.
The mess on mine is with the extraction hood in place for the whole job.