How do you apply decals to a curved surface?

Most model kits will come with decals to help the modeller to add that final level of detail to a kit.  Additionally, there are many decal manufacturers that will supply 'after market' decals to help a modeller to provide a very specific look to their kit.  One of the trickiest aspects of working with decals is how to get them to adhere to an uneven surface.

Most decals are printed on backing film and are waterslide, this means they will separate from their backing sheet after being dipped for a short duration in tepid water.  Sometimes the surface tension of the decal carrier film means that it is difficult to apply to highly curved or uneven surfaces.  Without assistance, this can mean that the decal fails to sit properly on the surface or may sit proud of the surface.  This may result in a distinctly less than satisfactory result and can additionally mean the decal is more likely to be dislodged.

Thankfully there are a number of readily available solutions to this problem.  A number of manufacturers have produced products which in essence will soften the carrier film allowing the decal to adhere and contour to the desired surface.  Some of these options are single solution items such as Humbrol Decalfix.  Other manufacturers offer a two-product solution that works in tandem to achieve the same result.  Take for instance the Micro-Set and Micro-Sol products offered by Microscale.  Micro-Sol helps to soften the decal, essentially assisting with accurate positioning and allowing the decal to lie flat and contour to the required surface.  Micro-Set can then be applied, aiding in decal adhesion which in turn helps to remove unwanted air bubbles giving that 'painted on' effect which can significantly aid the realism of the model.

Vallejo also offers a very similar two-stage solution.  Vallejo Decal Fix helps to prepare the surface and allows for decal adhesion.  This can then be followed by Vallejo Decal Softener which helps to soften the decal allowing it to contour effectively to the required surface.