Decals need two things: an adhesive which will help them stick to the model better (especially true for bare plastic) and softening agent which will mould the decals to the surface. Classic solutions involve two fluids which complicates things and makes the two bottle sets more expensive. VMS Decal Set & Soften (AX09) is a single product that does both jobs better and is not as aggressive as the classic fluids.
VMS also produce a 2 part set AX13S ( setter ) & AX13C ( cement )
This classic solution includes two separate fluids that will get the job done for you in the proven way. Fantastic adhesion achieved with proprietary adhesive formulation thanks to the Set & Fix fluid and conformity to model shape thanks to the Softener fluid.
Use: Apply the Set & Fix fluid over target area and then apply the decal. Squeeze excessive fluid out and wipe it away with a brush soaked with water. To mould the decal apply VMS Decal Softener over the decal and wait 1-3 minutes. The decal will soften and adjust to the surface of the model. You can use acotton bud to help the decal conform to the surface, perform gentle tapping motion. Do not get the softening fluid on the paint job as it can dissolve the paint (true for any softening fluid brand). If the paint reacts with the softener simply introduce a bit of water to neutralise the softener and leave the paint be, it will revert to its original state. After 24h seal the decal using VMS Varnish HD ( AX05 ). Due to the multitude of decals on the market and varying thickness of carrier films always check if the softener is compatible on a spare decal first!