Gluing pvc foam core

Hi,
Currently building an international 14 in a female mold.
First skin to be laminated with epoxy.
What would be best to add to the epoxy resin to glue the pvc foam core on the first skin once it is cured?
Phenolic or glass spheres? anything else?

Maybe add some thixotrope material (fumed silica) if the epoxy is thin...

[gonzo]

If the skin cures there will be a bonding problem unless the surface is prepared. Epoxy forms a layer of wax in the surface after curing. The best solution is to lay the foam and outside skin together. Have you thought of vacuum bagging?

[T.R.]

Cover the first skin with a layer of peelply before it cures which takes care of the "wax"-problem, it ensures good adhesion when removed after curing . Add some silica to the epoxi to make a " slurry" type mix. You should first roll a thin coat of unthickened resin onto the foam and the 1st skin before applying the thickened stuff with a brush or a squeege. A good tip to get a good result is as mentioned to vacuumbag the stuff down. I´d also do the hull in 3 "hits" , 1st skin, foam 2nd skin.
good luck
TR

Thank you very much all:
I can bring some precisions about the project here.
I will vacuum bag the first skin with all the necesary stuff: peelply, perforated film an bleeder.
I was thinking about gluing the foam right after laminating but i read that it would possibly mark the skin and be visible once out of the mold.
Usually cored hulls are made in three shots and it involves gluing the core under vacuum after the first skin has cured.
I have tixothropic but i think some other kind of microballs are used in the preparation of such a glue.
There are several options and i have a brand new drum of phenolic but i do´nt know if it will do...