Airfix 1/48 Tiger Moth

The struts fit into recesses under the top wing and leave some rather big gaps. Now I know that unless you turn the model upside chances are you won't see them however I know they are there so I filled them.
I generally use a solvent based model putty such as Revell's Plasto but as it bites into the plastic you end up losing a lot of surface detail when sanding the stuff off. With that in mind I used AK's Modelling Putty as for jobs like these you fill the gaps, let it set but instead of sanding you can remove the excess with a cotton wool bud (Q-Tips for any American readers of my blog) soaked with IPA (Iso Propyl Alcohol). Doing it this way preserves any detail;

Much cleaner and quicker than sanding. The putty does have it's limitations but for gaps such as these it's ideal. I'm not one for some of the gimmicks and snake-oil salesmen in the modelling world but this stuff I like.