Where to get screens for MC21 in LEXAN polycarbonate, preferrable double screen.

I have 4 broken acrylic screens lying around and just broke a piece of a new one when tightening a bolt.

DIY: How hot should a LEXAN polycarbonate plate be to sink down in a mold ?
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Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom