quick spackling fill question

Quick Question… Any problem with using DAP all purpose spackling paste on a poly (millennium foam) blank that will be glassed epoxy? Just trying to fill a weird little spot…

DAP Fast-n-Final used to be the favorite until they added the grey paint/primer to it.
Sherwin Williams lightweight is a new favorite.
I have used Ace Hardware store brand lightweight with no issues. All my stuff is EPS and epoxy resin.
Dilute with distilled water if needed (someone once said ‘tap water is crap water’ when it comes to thinning spackle).
Do not add Future floor polish because it will be a horrible mess to sand.

Nice !!! I appreciate it.

Thank you so much for your insight!

Delam…?

Its actually for a broken swallowtail on a blank I shaped. Havent glassed it yet but glued it together with gorilla glue. The glue settled when it dried and there is a skinny crack that I’m filling.

Red devil.