[xavieralexandre]

Most plywood is glued with phenolic glues whereas melamine glues will behave better with a laser: https://n-e-r-v-o-u-s.com/blog/?p=6042

[elihu]

I've found that plywood that comes in 4'x8' sheets usually uses phenolic glue, whereas the stuff that comes in 5'x5' squares usually doesn't. "Exterior grade" or "marine grade" anything is also a strong predictor that it uses phenolic.