Well, you would too!
I’ve just looked at the tutorial for making HDPE clamps and thought “I can do that, and they would be useful”, so trotted off to Amazon to look for a board - then almost fell off my chair!
The smallest sheet nearest to 1/2" thick is 1m x 1m x 12mm and costs £140 (about $180!).
I think I’ll use 18mm ply - as I’ve got shed loads of it!
Hey Peter,
Amazon is not the only Skywalker. There is another:
https://www.plastock.co.uk/pe300-hdpe-extruded-natural-sheet has that sheet for £78.
and another:
https://www.trentplastics.co.uk/hdpe-black-sheet has a 12mmx250mmx250mm for £5.16
Thanks, @Gerry.
To be honest, I didn’t stay there for long and managed to find somewhat cheaper suppliers 
I’ll take a look at your links, too!
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
That’s awesome 
That looks like allot of fun
OMG. How long did it take to de-static that thing?
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)
The other thing you can look for or ask around at material suppliers is a UTILITY grade HDPE. Typically black and a fraction of the cost.
Locally a 4’x8’ sheet of 1/2" utility grade HDPE runs $120 You can make alot of cool stuff out of that!
That looks like a low budget horror film about an insect invasion.
And they are after my beloved Shapeoko and spindle !
Not that it would be a “Good” test, but when you see something like this picture, would it suggest that the rails and the spindle are not grounded?
The spindle body is, because I made sure of that. Rails…I have not done anything to ground them.
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.
