Mikael,
Try the hairdrier on medium heat but still as hot as your hand can stand for a few seconds, then smooth down with a lint-free cloth.
Let's just stop to think about the physical/chemical processes involved in getting decals to sit down over detail or around tight curves/over edges (rudder decals etc). Firstly, consider the decal's manufacturing/printing process. This can be, generally, one of two types (dependent on the printing process used in their creation), either laser printed (such as Aviattic or Wingnut Wings "lozenge" decals) or screen printed as in Pheon or (most) WNW marking decals (some of their more elaborately shaded and blended designs are laser printed, even though they appear on the same sheet as the "conventional" screen-printed decals.. a neat trick by Cartograph!).
The method of production denotes the fabric of the decal itself:
Laser printed decals are printed onto decal paper which already has a carrier film or varnish coating over its entire surface and it is this coating which forms the body of the decal, with the design laser-printed onto its surface.
Screen printed decals are successive print layers of different colours laid down as thin layers of acrylic ink onto the decal paper's surface, or on top of a previous ink layer, with the final layer forming the transparent carrier film or varnish. Screen printing is a time consuming process, as each individual layer has to be completely dry before the next is applied - in the case of some of our more colourful decal sets, as many as twelve different layers are printed, each one a separate process where the "register" or "overlap" has to be controlled with enormous care ( we regularly ask Fantasy Printshop to deliver register accuracy of 0.075mm!).
Next, consider the actions of the various potions sold to allow or, more correctly, to force decals to conform. These potions divide into two distinct types: the "wetting agent" (as in Micro Set - the blue bottle) which serves to break the surface tension of the water in which the decal is floated onto the model and is composed of a relatively benign chemical - exactly the same effect can be obtained (much more cheaply) by a few drops of dishwashing liquid dropped into the decal water. The second type of magic potion is a very different chemical agent, often acetic acid (smell Micro Sol!) with other variations of varying concentrations/strengths. These agents chemically dissolve the screen-printed ink and as they evaporate and the decal dries out they should (note SHOULD), deposit the ink back on the surface, hopefully in the same order in which the different inks were printed. Sometimes (very often with the stronger brands) the thin ink layers of quality decals (such as those made by Cartograph and Fantasy Printshop) get mixed and scrambled by the dissolving process, leaving you with a complete mess. I admit to being unsure if these liquids have the same effect on the varnish layer of laser printed decals but suspect that they might.
NOW (I hope you're still with me, because this is the important bit), the application of heat to both types of decal also softens the decal itself, and thus allows it to conform to the underlying surface but, crucially, without risking the possibility of damage inherent in the dissolving process. A possible problem with too much heat is that the decal dries out and the glue layer then will not adhere to the model - a deft swipe of a small paintbrush lightly loaded with a water-soluble varnish ("Future"/Kleer work very well also) is often useful if applied as an additional/replacement adhesive beneath the decal, straight after the heat is removed, allowing the still soft decal to be smoothed down over the surface and adhere tightly - this method also ensures that there is no silvering visible on ANY of your decals.
The heat method has its own dangers; too much can fatally damage the decal by melting it into a crumpled mess and of course the underlying paintwork and even the plastic of the kit itself can melt with too much heat - but honestly, if you keep your own hand/fingers in the "line of fire" from the hair-drier, you'll remove the heat long before your decal (or the kit) is anywhere near getting damaged.
I've banged on about this subject at similar boring length before and a number of my customers have told me that they have used the chemical agents with total success, so the choice is yours. It does, like any worthwhile modelling technique, take a bit of practice, but for me the hair-drier method is one I use every time and I still don't recommend the use of expensive potions magiques, reserve them only for Asterix et Obelix!
Rowan
(Pheon Decals)
