Platen repair experiment… This platen on a Royal Arrow was badly cracked with large chunks missing. So, having nothing to lose, I took some black Flexseal paste and filled it in like spackle. Of course, I applied way too much and ended up sanding most of it off before applying 240 grit sand paper to the entire platen via my drill. It’s smooth to the touch, not perfect, but passed the typing test with all letters clear and neat.