BT spiral filling

[Terrier]

I,m in the middle of my RIM-2 Terrier project and I have a problem filling the spirals on the Aerotech tube. What can I use to fill the spirals without spending hours sanding the excess away. This is only the prototype, but I need a somewhat smooth surface. I was thinking sandable primer. What do you guys think?

 

[Terrier]

Read before you write. I just looked thru the threads and lo and behold, I found my answer. I guess that I opened my mouth too early again