Epoxy build up before varnish?

[SeaHusky]

I have removed all my bulkheads and sanded them down to bare wood.
My intention is to properly glass them to the hull and then either paint or varnish them depending on their location.
To make things easy i meant to give them a couple of  coats of epoxy first. This would a) give great bonding when glassing to the hull and b) build up a base layer on to which i can apply a couple of finishing coats of varnish instead of having to do the 8-10 layers of varnish.
This is a method I got from YouTube but I have now been told that I may get cracks in the epoxy beneath the varnish which would ruin the appearance.
Does anyone have any experience or advice about this method?

[CharlieJ]

Inside the boat you should not have any trouble with varnish cracking. Do be sure that you sand those bulkheads well especially where the tape will go.

Personally I've stopped using epoxy under varnish on the outside- simply too difficult to go down  to wood when (not if) you need to. I do still use under paint

[SeaHusky]

Thanks!
I will see how I choose to do it.