For decal application I use warm soapy water. Sounds like you have large decals so.....
This technique work for only non-paper deals.
Wash all parts with warm soapy water. Rubbing alcohol can be used to remove grease or oil. Above all, do not touch any surface where a decal will go after it has been washed.
Get a small tub or pan and put in about 4-6 drops of dishsoap per liter of water (just enough to make it foamy)
Wash your hand several times with soapy water.
Peel a decal, only handling the edges and outside face, and dip in the soapy water.
Set it down lightly in the area where it wil be placed, and slide it gently into position.
While wet, it will be easily slid or peeled until it is pressed upon.
Using a thumb, credit card or small squee-gee, start from the center of the decal and squee-gee the water and air towards the outside. Work your way around the decal, always starting from the center.
After all decals are applied, take a soft cloth and squee-gee the decals again. Be sure to press the decal into any low countours very thoroughly.
If there are bubbles under the decal, use a pin and puncture them in the center with a tiny hole. Work the air or water out through the pinhole.
Leave all the parts out in the sun for a day to further evaporate any water.
The dish soap will not harm the adhesive or compromise it's bonding integrity.
