Filler putty question

[hampton]

I am fairly new to the use of filler putty, I am wanting to fill in the gaps on my fuel tanks of my Dodge l700 kit as well as a few other areas with some gaps. I new to know how to use it, whether or not to prime the surface before use or after and want to give it a good smooth apperance when finished any pointers or tips welcome thanks for all the everyone has provided so far.

Oh and what brand you recommend using!!!!!!!!

thanks

[plastictrucker]

this subject has been covered in this section all ready.have a look.