Welding masks may not be rated for solar, but given that they block out the insane amount of UVA-UVB generated by welding, and our atmosphere totally kills UVC,

Welding masks may not be rated for solar, but given that they block out the insane amount of UVA-UVB generated by welding, and our atmosphere totally kills UVC, you're good to go as long as you aren't relying upon the auto-darkening ones.