Which has better adhesion....

[Roly]

I understand the air retardation of polyester for subsequent coats but....
Which has better adhesion....
Mechanically bonded polyester to polyester. (I know this works)
Or, mechanically bonded epoxy to polyester?

Does the styrene content of polyester give it any more than a mechanical bond
on fully cured polyester?
Would vinyl ester be a candidate?
I want to strengthen an already fully cured surfboard with carbon uni. down the stringer.
I just snapped my favorite board.

The thickness & density of current surfboard foam & the glass shell thickness form an unbalanced composite.
Next board I make will have a balanced composite panel rebated in deck & bottom.

[lewisboats]

Epoxy to polyester, sand the poly to give it tooth and the epoxy will do the rest. It is a better bond than Poly to poly.