That's a nice model, Ajidica, I didn't even know Revell made that. Without using putty, for a gap like the one you describe, I suggest you might try applying some PVA glue along it with a cocktail stick/toothpick, or similar, and wiping off the excess with a moistened cotton bud/Q-tip. Work in small sections - an inch or so at a time - and reapply small amounts in any areas where you take too much off. The PVA will fill the gap and it dries clear (leave it overnight). If you find it has shrunk back, redo the affected bits, let it dry again, then paint. Hope this helps.