I have an ash board, pocketed with epoxy resin fill. I will McFly the surface flat. I want to glue .060 thick oak veneer then v-carve to get 3 colors . I plan to v-carve thru the epoxy to expose ash.
If you already have epoxy down, the solution is more epoxy.
As a specific recommendation, I’d suggest finding your local West System retailer and snag the West System User Manual & Product Guide. I only recommend West System because I know their products and have a local retailer. Substitute “West System” for your locally available epoxy.
I would use West System 650. The 650 is a toughened epoxy that works incredibly well with red and white oak. It’s basically designed to secure anything to anything else and it can, technically, be used underwater. Somehow.
Separate response so @WillAdams can save it 
I’ve used that in the past, and even recommended it, but since I have found some of their recommendations to not work well — that was why I posted:
other manufacturers have similar pages, and seem a better reference (save for the need to consult multiple sites and decide between vendors).
Ugh, that’s terrible to hear about the website, but I agree about just using a manufacturer’s website. That West System book is great and taught me how I can repair my kayak if I need to.
I’ve focused on a small number of glues that I can acquire locally. For me, that’s been West System and Titebond. With an exception made for hide glue, but I have 15 pounds of hide glue and that’s close to a lifetime supply.
Some friends bought a bunch of EpoTek (it’s high-end, fancy, space epoxy that is also the same color as cherry when it dries). It’s amazing stuff, but you have to order $600 of it at a time and it goes bad so many months after manufacture.
Veneer - anything works, honestly. Even the right hide glue will hold up for about 150 years or more, unless you’re on the Indian subcontinent or in southeast Asia.
