u/Blatant_disregard23

I'm trying to make a Captain America shield for my 4 year old, I got the shield pattern all cut and glued together, now I know my cuts aren't perfect 90° but it'll do the job. My problem comes from the seams still showing even after doing the quik seal and sanding method. I get these nasty sanding marks left, should I go over it again with some more kwik seal or switch to a finer grit sandpaper? Any tips on how to hide seams better?