Advice sought on reglassing panel joints

Seeking advice on a mistake I made and need to correct.

I have to cut and move several foam core panels in my boat build....move them. These are structural panels. Currently they are, I think, nicely set with 2 progressively wider layers of heavier biaxial cloth/epoxy.

So then what? Should I just treat them as a brand new joint and add 2 more layers of cloth and epoxy over the first layers.....the same exact size? Or does the fact that the old cloth is still there mean I should have some type of different strategy to get the same (or similar) strength?

By the way, I am NOT going to be grinding down the first 2 layers of cloth....I know that adds weight but just going to leave them...

 

Welcome to the forum.

You'll have to do some grinding to insure a clean and sufficient contact patch with the previous work. It also permits you to have a seamless, flush repair. Typically you'd taper the old work to the new at about 12:1 ratio for best strength.

 

I'm a rookie, but I'd grind them to a feather edge and for bite and if the joins are 4", I'd go to 6", 6" to 8". If they are already 6",8", I'd just redo them the same, but that is just me. If you don't have wider tapes; you could use fabric if the weights and glass angles are right. Mat is only helpful to keep things straight, but adds very little in strength or so I've been told. I had some rework lately myself, far worse than yours.