Stubborn Join Keeps Coming Unglued

Gotta hate that. I do that when I am drilling a hole at the end for an antenna or a pedestal on the bottom of a hull.

Try a more mechanical join. cut a 1/2" slot crosswise across the seam in a couple places, stick a strip of styrene down in there vertical, trim, sand, paint.

I use gel CA a lot for seams like that.  The gel is useful where the fit is not perfect (ordinary CA will NOT fill any gap, even slight ones.  And, the gel stuff is far less brittle. And, it is slower drying for longer seams so the stuff you put on first has not set yet when  you get the sides finally put together.  Use a fresh bottle/tube, as it thickens as it ages.  Neither gel nor regular CA has much of a shelf life once it is opened.  If it thickens with age it will not soak down into the joint when you apply it from outside- that is why you need the fresh stuff. I use Locktite gel CA- very good stuff.

I think I found a fix.  Three times I made the repair using Ambroid solvent, CA and combinations of these glues.  I then welded a 1/4" x 0.025 styrene strip along the join and used copius amounts of Plast-Struc solvent.  I then used successive thin coats of Tamiya filler to feather the edge.  Hopefully this will do the trick.  The C130 has been on the bench over two years and I would like to finish.  Fingers crossed!

AHA :

  You jumped the gun ;

I was going to suggest this .If you had the cargo door open you could insert a piece of flat styrene -  .020 . cut to length and width from the inside and this would help solve this issue  .Mine did that too .I hadn't painted yet so I did that after pulling the fuselage apart carefully .

Unfortunately, my cargo door had such a bad warp and fit, I had to seal it closed with copious amounts of CA and putty.