What filler/putty to use for spray rails?

[dberr]

We are building some 5m RIB hulls with VE and Iso resins. Our hull has two spray rails. One is quite large and creates lots of challenges with bridging in the corner when we are laminating. I have seen photos of other power boat hulls where the spray rails are filled in with a putty to make laminating easier. We have a structural filler available, but we would need to make 3 or 4 passes with this formulation to prevent cooking the mold. Does anyone know of a putty that can be applied thicker than 1'' in one pass, or am I asking for the impossible?

[USCGRET/E8]

I've seen Bondo used, but not sure about the 1+ inch though.

[dberr]

Thanks USCGRET/E8. I have never tried auto body fillers in a hull. I will look into other marine grade fillers, i.e. 3M VE based fillers.

[alan white]

Might make sense to mold the rails seperately and adhere with a good two-part adhesive. You could mold a shallow channel into the hull (1/16" x rail width) to position and align them and to hide the glue line. The advantage is an uninterrupted lay-up and a very controllable operation. Also, there is the option of an applied vinyl spray rail, which I think can be purchased in lengths.
I've seen those on a few boats.

Alan