Applying decals and water slide transfers is not too difficult but getting professional results does take some knowledge of the processes you should use.
Tools that you need include sharp scissors, a hobby knife with a sharp (new) scalpel blade, a steel rule, wooden skewers, a small paint brush and tweezers. You also need clean water, a new kitchen sponge and a shallow bowl, decal setting solution and paper towel or absorbent cloth.
Measuring tools such as a clear plastic ruler, a vernier caliper, spring adjustable dividers and a magnifier are also useful for checking the exact position of each decal.
Make sure the surface is clean and dry and has a gloss finish. It needs to be free of dust and imperfections. Use a clear gloss over a matt finish as decals will not adhere well and you will get a silvering effect from the clear backing. A model stand or holder is useful so you don’t leave finger prints on the paintwork.
Identify the exact location of the decal by measuring from at least two reference points such as from one end and some raised detail. Check if it is square to or parallel to one side or one end.
To prepare the decal cut the backing paper as close to the edge of the decal as possible using the hobby knife and steel rule. Sharp scissors are good for curves. For tiny hard to read decals keep them the same way up as they come on the sheet otherwise they may end up upside down on the model. You may find it easier with some very large decals or long stripes to cut them into smaller sections to help them conform to contours, louvres, ribbed or raised surfaces. Join them back together again on the model.
Put the sponge in the bowl and fill with clean water until level with the top of the sponge. Use distilled water if the tap water leaves any traces of salts or impurities on the model when dry.
Place the decal face up on the sponge and leave for 30-60 seconds until it moves freely on the backing paper when prodded with a wooden skewer. Use tweezers to place the decal with backing onto the model face up in position. Lightly hold it in place with the skewer and slide away the backing paper with the tweezers.
Adjust the final position of the decal with the paint brush and the skewer. Re-check the exact location as eyeballing it just won’t do!!!. Check it for square and for parallel. Re-position if necessary until you are satisfied. You may need to add more water with the brush to get it to slide to the right place. Carefully dry any excess water with a paper towel or absorbent cloth without moving the decal.
When you have applied all decals to one side, brush over each one with a decal setting solution. We use Mr Mark Softer however others also work. This removes excess air bubbles and pulls the decal snugly over the detail and into the paint surface. You may need several applications with really difficult surface details and you may need to prick persistent air bubbles with a needle or sharp knife to get the decal to sit properly.
When dry complete the other side. Then apply a protective finish such as Humbrol or Floquil or Testors in clear gloss, satin or flat to seal them. Weathering should be done before the final finish.