I’m lasering some coasters using the proofgrade maple ply, which obviously has a nice finish on it. But I’ve burned away the finish where I’ve lasered a lovely flower design. Do I need to seal the flower design (burned away part) so the coaster can have a longer life?
I probably would. I created a nice little kitchen brush holder and deliberately left it unfinished to see how long the unsealed plywood would hold up to drips from the brush and sponge, and it did pretty well, but after ten months of abuse, it finally started to swell.
You may find this thread helpful: