UHMW
For my H23.5, I bought a 12x24 piece of UHMW from an industrial plastics company. I think it cost $3 or so. I didn't have the right tool to make nice smooth curved cuts, but managed to do well enough.I'm pretty sure that I called the factory and was told they use UHMW. However, the guy told me "UHMW, such as Delron". When I contacted the plastics company, it turned out that Delron is not UHMW but something quite different. Just now, I failed to find out what Delron is made of after 10 minutes of Googling. UHWM is much easier to find in small quantities, and cheaper, so I went with that. It's been two years now, and it seems to hold up.UHMW stands for Ultra High Molecular Weight polyethylene. The link below is just one picked at random from a Google search. There are many variations of UHMW. The link below doesn't mention it, but I believe there are blends to provide higher UV protection, for example. Given the location of the shims, I don't think UV exposure is a big deal, not for $3 worth of plastic, but I'd opt for it if available....RickM...