Fill the scratches in wood and Ferro cement

[Sea Hill Billy]

Hi all, I have recently purchased a Ferro cement yacht and found and removed the laminate on all wood and cement to find the previous owner used a drill or similar to scratch all the surfaces for the glue to bond with the laminate.

I now have removed all the laminate and been covering and sanding the all surfaces with a multi purpose outdoor crack filler. I have sanded 50-65 % of it off the surface just leaving the cracks filled and slight uneven surfaces.

My finished product or top layer im going to be painting on is a 2K motor paint sprayed on in layers.

My question is:
Should I add a epoxy based layer on the finished sanded crack filler to add strength to the paint when moisture may enter the area and cause is to crack and bubble, or shall I just apply more coats of 2k paint?

The 2k paint has already been purchased and sanding crack filler done. I would really appreciate opinion based whether to apply a epoxy layer between the filler or not. I understand that it's not as per the way things go on a boat as I'm struggling to get this finished so I can live on her asap as I'm moving on the yacht in 30 days. Thanks in advance.

[Benz]

Most 2-pack paints recommend a proprietary primer underneath...check the package.
I'm inclined to always use primer under paint, just because it helps to even out the texture. Fillers are often more porous than the adjacent surface, and un-primed, the texture difference is very visible.
I can't speak to waterproofing, but again, a nice epoxy-based primer like Awlgrip 545 can never hurt, and is a joy to use.

[tkeithlu]

Welcome to the forum, Sea Hill Billy.