This page will show how I go about applying decals to my models.  

1.  Setting solutions are a lifesaver when it comes to getting decals to conform to the curves and contours of a model car body.  The most important thing to remember when using setting solutions is that you have to let the solution do the work.  They will soften the decal material and melt it onto the model body.  If you touch the decal after the setting solution starts to do its work you will run the risk of ruining the decal by deforming it.  I use the following solutions for my cars - the blue bottle is Microscale Micro Set and red bottle is Microscale Micro Sol.  I've heard some people say to use the Micro Set for mild curves and contours while the Micro Sol should be used for more extreme applications.  I actually use both for all of my decals as you will see below.

2.  First step is to plan your attack when applying decals, you need to make sure that if your car will use layers of decals that the underlying ones get applied first.  The car I am applying decals to is the Power Puff Girls car.  The first decal I will be applying is the driver's side rear quarter panel.  I cut the decal off of the set and trim it as close as possible to the graphics.  You will also want to make sure that the model body is clean from lint and dust before starting.  As you can see in the photo, this decal will cover the area around the rear wheel opening as well as surround the bottom of the side window by going up the B and C pillars.

3.  The next step is to dip the decal in warm water.  After doing so, set it aside.  While the decal is loosening itself from the backing paper I take a paint brush and apply a liberal coat of the Micro Set solution (blue bottle) to the area of the model that will be covered by the decal.  Don't worry about being exact in the area you are covering as the solution will not cover evenly.  This isn't a big deal as the wet decal will spread the solution around under it when you slide it onto the car body.
 

4.  When the decal slides freely on the decal backing you can slide it onto the body and position it where you want it.  Do not force the decal to slide - if it isn't loose, let it sit longer.  By not waiting you will rip the decal and cause more problems.

5.  When the decal is in place, take a soft paper towel and lightly press the bubbles out from under it.  Start in the center and work your way to the outside edges.  If the decal shifts position on you, simply re-wet the decal by dipping your finger in the warm water and spreading the water on the decal.  This will loosen it from the model body allowing you to reposition it again.  Once it is back in place go back to pressing the bubbles out from under it.  As you can see in the photo below, the decal is laying pretty smooth except for the overhang on the window openings.

6.  This photo shows the overhang around the wheel opening as well as a couple ripples at the top of the wheel opening.  These ripples will disappear with the setting solution.

7.  The decal at this point shouldn't move very easily.  Double check to make sure it is still in the correct position.  At this point I apply the first coat of Micro Sol (the red bottle) to the decal.  I apply a light coat with a soft brush.  It doesn't take much to get the job done although sometimes it takes a couple coats.  I have found that several light coats is better than 1 heavy coat.  NOTE:  On real small decals you may shift the decal when brushing on the Micro Sol.  Have a toothpick ready to reposition the decal as soon as you are finished applying the solution.  If you wait very long the decal will be too soft to move and you will only end up deforming the decal.

8.  This is what the overhang on the wheel well and rear quarter window looks like when the Micro Sol solution is first applied.

9.  Here's where it starts to get scary.  The decal will start to wrinkle up and it seems like you have done something to destroy it.  Do not touch the decal to try to flatten it or reposition it at this point!!!

10.  Sometimes it will be necessary to make some relieve cuts to help the decal settle into position.  In this case I am going to make a small cut right in front of the B pillar.  Make sure you use a sharp nice for this to avoid tearing or moving the decal.  It is a good idea to let the decal solution set up a little so it doesn't move when you go to make the cut.  This photo is taken about 1 minute after the first coat of Micro Sol is applied.

11.  This photo shows the small cut in front of the B pillar.  The decal still looks terrible at this point but you can see how the setting solution is starting to work.  The decal is starting to wrap itself around the wheel well and window openings.

12.  More wrinkles.......  At this point I lightly brushed on another coat of Micro Sol.  This is about 2 minutes after the first coat of setting solution was applied.

13.  From a different angle....

14.  The wrinkles at this point still look bad but you can see that they are looking "tighter".  The decal around the back window is almost completed wrapped around the opening.  The wheel well is also making some progress.  I apply another light coat of Micro Sol at this point, which is about 3 minutes into the process.

15.  We're getting close now.  only a few wrinkles left above the wheel well and on the C pillar.

16.  At this point I apply a fourth light coat of Micro Sol to any problem areas that still have wrinkles or haven't wrapped around the body.  If there are any over hangs that do not want to wrap around the body you can coax the decal with the brush you use to apply the setting solution.  All it takes sometimes is to get the decal leaning in the right direction and the solution will take it from there.  This is about 4 minutes after the first coat of setting solution.

17.  This is the decal after about 7 minutes.  As you can see I have moved on and applied another decal as this one was drying.  The decal has laid down nicely at this point, just a couple very small wrinkles above the wheel well and by the C pillar.  Leaving it sit for a few more minutes will result in those disappearing as well.  You can also see how nicely the decal wrapped around the wheel well.

18.  This shows how the decal wrapped around the body.  Looks much better compared to the photo earlier that shows the overhang.

19.  Here you go, the decal is on the body.....  time to move on to the rest of the decals.

20.  Another shot of the decal process for this car.  On the hood, if the decal goes onto the fenders, you will want to tape the hood shut from the inside to keep it from moving around.  After the decal sets up for a couple minutes, take a sharp knife and slice the decal using the hood opening as a guide.  Follow that up with a coat of Micro Sol around the opening. The decal will wrap itself into the opening making for a nice clean application.

21.  The finished product......