I am building a Hnagr 9 P-47 ARF that comes with CA hinges and precut slots. I would like to discard the CA hinges and use Robart pin hinges can anyone tell me a good way to do this should i fill the CA hinges slots or use those slots to drill for the Robart hinges?

I would just drill for the Robarts and install them using Gorilla Glue. The glue will creep into and fill the slots. Care must be taken to not use too much glue as it will create a mess if you do.

I find that there is usually not enough backing for the Robart hinges so it requires opening up the covering and installing little blocks...Installed properly the CA hinges work fine...

I was thinking the same thing.

You can see the blocking for Robart Hinges in this pic.

Personal choice, I also like using Robarts but I also build blocking into my surfaces.

Bob

I do what Sensei does and create a tube\ pocket forf the hingepoint to slip into allowing the adhesive to "hug" against the splines, otherwise the glue just pushes out the hole, as well as a good portion of the hinge point....

On my last ARF I used the Dubro heavy duty hinge with cotter pin to replace the CA ones. I used a metal nail file with point on it to open up the slot so the hinge would be easier to slide in. For final assembly I used Gorilla Glue and it worked out real good.