Here is a hack for loose or lifting decals. This is not for setting new decals like waterslide ones.
Get a piece of wax paper and go grab some hairspray. Chances are you already have these items in the house.
Cut a small piece of wax paper that you can work in any direction with your hand. Either spray or find a way to drip a drop of hairspray onto the paper, especially at the corners, and wait a minute or two to let it soak and sink into the paper. Make sure there are no hairspray blobs.
Slide a corner of the now-sticky wax paper underneath the loose decal very lightly, almost like you're just skimming it. The wax paper is thin enough to get under and soft enough that your decal won't disintegrate upon contact. This should make the underside of the decal sticky again.
Use one of the door opening tools that come with a model and gently tap the top side of the decal down.
You should be good. Works when you don't have decal setting solution.
Get a piece of wax paper and go grab some hairspray. Chances are you already have these items in the house.
Cut a small piece of wax paper that you can work in any direction with your hand. Either spray or find a way to drip a drop of hairspray onto the paper, especially at the corners, and wait a minute or two to let it soak and sink into the paper. Make sure there are no hairspray blobs.
Slide a corner of the now-sticky wax paper underneath the loose decal very lightly, almost like you're just skimming it. The wax paper is thin enough to get under and soft enough that your decal won't disintegrate upon contact. This should make the underside of the decal sticky again.
Use one of the door opening tools that come with a model and gently tap the top side of the decal down.
You should be good. Works when you don't have decal setting solution.