Advice Needed on AT-AT Box Repair

I recently bought an otherwise lovely condition Palitoy AT-AT box, but the old glue seal holding the cardboard together has completely failed along the long edge. Fortunately it still some of its original tape on one end, so the box is retaining its shape (just), but I would like to repair it by glueing the failed cardboard join back together again, partly to improve its appearance before I display it, and partly to greatly improve its rigidity so I can safely stack other boxes on top of it.

My question therefore is actually quite a simple one: is there a particularly good glue anyone can recommend to achieve this? Obviously many are available on the market, but I wondered whether any other collectors have had to repair boxes in their own collections and can recommend a make / type of glue which they have found to be particularly effective and doesn't risk damaging the box? I wouldn't normally dream of artificially altering a vintage box, but this one is on the verge of falling apart. Can anyone help? Thanks.

Only box I have repaired is a BIGTRAK box, completely trashed, glue seam you mention was ripped apart and all tabs were ripped off, I used PVA glue and some cartridge paper patches (that you won't need) to put it back together. Turned out really well IMO, just one small corner was missing in the end.

Thanks for the tip, it's very helpful.

Should have said, if you use PVA, you only really need a thin application (too thick and it may distort the card as its a liquid) and the patience to hold it in place while it sets up.

My thanks once again. Any idea how long I should expect to hold it together before it sets, please? Actually, thinking about it, because it's quite a long seam (60 cm), I suppose I might be able to add some small weights to the top surface to hold it in place while it sets.

One observation I ought to mention is that whilst the original seam has failed, whatever glue was originally used still has some slight tackiness to it, albeit far too weak to hold the card surfaces together. Will this impair PVA's ability to stick, do you imagine? I hope not, as I think it might be quite difficult to remove the old glue first if that was needed...

Oh, I'm far from an expert. I would think it'd be ok to adhere with the existing glue still partly there though, PVA is pretty versatile stuff and can sick plastic as well as paper (lightweight) and the weights idea while it sets sounds a very good one.
Timing wise, not long, only a few minutes when I did the BIGTRAK...

Put up some pics first so we can see what your on about be good to see the box as well.

Thanks again for the advice SAVORY100.

As requested, here are some photos of the problem:

It's a shame, because the rest of the box looks like this:

And this:

It even came with the ultra-rare Crayon Edition (TM) Instructions ;-)

A glue stick or normal school glue will work.

Love the coloured in instruction sheet, the kid actually did a damn fine job of it too. 8)

Ha! The coloured in instructions look great

Nice At-At box as well. Be careful gluing that back together

The instruction sheet is brilliant, love it 8)

Box looks great but that is the first time ive seen green snow, although I have heard of yellow :lol: