Fixing "steps"

I end up using putty or super glue. I have become an expert of late as I  seem to create them myself. Best thing is to prevent it in the first place. Sometimes it's gluing small areas at a time, or if you have a fuselage split in multiple pieces, like a front/rear along with a left/right (like Hasegawa's Phantoms ), then gluing the fronts/backs together followed by gluing the completed halves together.

If you know how to use 3M brand spray adhesive you can spray 600 grit wet-or-dry sandpaper to a wooden board. LIGHTLY drag the fuselage against the surface of the sandpaper backwards and forwards to even it if it's not warped, but wavy and the edges don't line up evenly. I've done this before. It works pretty good as long as go SLOWLY. You might have to sand away the alignment pins, but if you tape the two halves together after aligning them by hand you can run a small bead with a toothpick to the edges to join them. What you're doing is removing just enough plastic to make a better seam if not perfect. I use Elmers brand wood filler to smooth imperfections if you don't want to spend a lot of time filling. It's water based, easy to sand, dries in fifiteen minutes, no smell, and you can use it around anyone without making them, or yourselves sick. If you need more help, or a better explanation, or pictures just ask.

~ Cobra Chris

I also use Cobra's fix if there's a "wave" in the length of a join. Another thing that works is to glue narrow strips of plastic to one side that overlap the join, which helps align and reinforce the seam, then glue it in short stretches which are easier to control than doing a long run all at once. For other problem areas like wing to fuselage, lots of "dry-fitting" saves lot of pain. It's easier to add or subtract material to get a good fit than to fill, sand and scribe later.

Hope this will help you & happy modeling!

Mike

I always test fit fuselage seams.  If you know there is a mis-match, you can do some things that are too late to do after the halves are joined. If one side is wider than the other, sometimes making a couple of "formers" to draw the width in a bit may save some filling.  Sometimes you can fit up clamp supports to clamp and squeeze the wider side.

For any residual mismatch, I like to try working with both sides, filing and sanding the wider side and putty on the narrower side.

Sometimes the problem is not unequal widths, but an offset due to locator pins not being in exactly the right spot.  Two possible fixes for that.  First, try enlarging the holes/dimples on the female side. If that is still not enough, cut the locating pins off completely, like many of the European kits.  Makes gluing things together a little harder, but pays off in less seam filling.