I am part way through a build on an AMT XB-70, & some of the fit on the fuselage & fuselage / wing joint is pretty bad.
I have tried the Tippex method on the spine, but overfilled it & left it to long, its now rock hard - anyway thats my problem to sort out.
For the rest of the gaps (>1mm), the only things I have available at the moment are Humbrol tube adhesive & Superglue gel (I assume this is what you refer to as CA?). Can you reccomend which, if either of these would be most suitable.
I haven’t used correction fluid for many years, but from memory, the bottles of thinner which could be added to it smelled very much like isopropyl alcohol - you may be able to smooth it out using IPA, otherwise it should still sand down easily.
DO NOT, under any circumstances, attempt use tube glue as a filler. The solvent in it will soften (and maybe distort) the plastic before it hardens. It will also more than likely form bubbles in the joint.
Your superglue gel will be a better bet, though I haven’t used it as a filler either. If you do go this route, don’t leave it to harden too long before sanding, otherwise it will be considerably harder than the surrounding plastic.
I use either medium CA (Zap-A-Gap) or Milliput almost exclusively these days. I do have Squadron putty, but I have had little luck thinning and smoothing it. Avoid Testor’s putty at all cost!!! Another solution that I have used in the past on REALLY large gaps is to cut a styrene shim or use a piece of stretched sprue to fil the gap and file/trim flush. Try Swanny’s Models site for an excellent reference on just about any topic involving modeling!
If you have to use CA as a filler, sand it within the first hour, otherwise it’s like sanding diamond.
Your best bet will be to use squadron white putty. Dab a little along the seam, use a tooth pick to get it in there, then dip your finger in some nail polish remover (with acetone) and run it over the seam to smooth it out (and clean up the excess). let it sit for a few hours, then go over it lightly with some fine grit sandpaper.
Try stretched spru with liquid cement (glue) or the super glue (CA). The parts “trees” from the kit (sprue) can be heated and softened, and stretched to different diameters (depending on how fast or slow you pull the soft sprue). The strand or strands of stretched spru can then be glued into the gap and sanded smooth after the glue is dry. The advantage of this method is that you have plastic glued to plastic. Putties tend to crack if they are used in an area that is to wide or to deep. Another way to fill a gap would be to use strips of sheet plastic, say from Evergreen Plastics. An example of this would be to use strips between the wing and fuselage in order to fill a gap and/or correct the wing dihedral angle. This works really well where the joint being filled is under stress, that is a joint supporting weight. Try it you will like it. Cheers.
I use CA alot for this purpose. Mostly, I like to add a thin bead of it. One thing CA does as well is pulls the parts closer together as well as fills in the gap as it shrinks as it dries. Over that I’ll put in Gunzye Sangyo’s Dissolved Putty, Squadron’s White Putty or Tamiya’s putty.