I have had a problem recently with decals not adhering to my planes. The planes are glossed varnished ,and after drying the plane is decaled.Decals are cut out dipped in hot water for a few secs and removed.I then wait for the decal to loosen from its backing and then slides into postion.After drying I find that the decals have not adhered,and fall off easily.The decals are mostly tamiya kit decals,but sometimes occur to other brand. Please help.Harry