To make a good model you are going to need putty because on a the real aircraft you are making a model of there is not going to be gaps in the fuel tanks or wing. To fill gaps you can use gap filling super glue or putty. I like to use this putty because it is water based which means it is easy to sand down which saves time. But it is easy to fill gaps using a damp cotton swab which allows you to get the extra putty off which also means less sanding. This putty performs great at getting in gaps of all sizes and will defenataly improve the looks of your models by making the gaps dissaper. And for the price you just cant beat this putty

Testors Plastic Putty is a good putty for a cheap price. When I was using it to help fill in some spaces in my F-5 Tiger II model, I noticed that it dried very quickly. (Hint: One must ALWAYS put the lid back on immediately after use. Squeeze gently to prevent a slow pouring of putty that, if the lid is not put back on, will dry quickly and be wasted. However, when I first squeezed the tube, only a clear liquid pours out before the more solid putty comes out. I do not know how to prevent this.) Once the putty was put on the model and smoothed out, the paint went over it nicely with no problems. I would definitely recommend this putty as a good, cheap alternative to other more expensive putties.

I've tried both the Tamiya and the Testors putty and personally I find the Testor's one to be better. This putty dries uniformly and not too quickly, making it easier to apply than the Tamiya one. There is also no smell.