The application of vinyl signage is simple, but does require close attention, in order to achieve best results.
All vinyl films require a backing tape, and this is applied over the entire surface of the signage, after you have removed all unwanted areas, such as around lettering or portions of vinyl inside letters/numbers. For example, removing the material inside the letter D. This is known as Weeding. Once you have carefully weeded everything you don't want on the surface, apply backing tape over the entire sign. This is best done in one length, but depending on width of the application tape itself, may require more than one strip. Application tape comes in a range of widths, and should be purchased in a width comparable to height of your lettering (if single row). It comes in two main varieties, paper and clear. The paper is more difficult to see through, naturally, and if using this type it is best to align the tape with top or bottom edge of your sign, so you have a reference point when applying. The other type is clear backing. The obvious advantage of this type is greater visibility when application, and is best used if you need to align to something which would be under the tape during application. Personally, I use the paper backing tape. It has a very desirable property of coming away easier from the lettering after application of sign, if you spray water or application fluid onto it.
This is applcation fluid. It is sprayed onto the surface to take the sign, and sometimes onto the back of the lettering itself. It makes things sooooo much easier, because it eliminates adhesion between surface and lettering. Spray a light coat of application fluid onto the serface where sign is to be applied, and you can move the entire sign around until you are satisfied with the location. Please read the instructions carefully. I don't use store bought app. fluid, in preference of plain water with a VERY small amount of kitchen detergent. Just a drop or two suffices my needs.
Once you are happy with sign alignment on the vehicle, you can begin permanent placement, by removing all space (and application fluid) between the lettering and vehicle surface. Starting at the centre of the sign, gently but firmly run a squeege from centre to edge of sign. There is no rush here, and it is important to be thorough. If done correctly, all air and fluid bubbles will be removed from beneath the lettering. Take care not to press so hard that the sign moves while using the squeegee. You can use a stiff piece of plastic as the squeegee, such as a credit card sized 'loyalty card'. You know, the kind of card businesses offer frequent customers. A body filler applicator can also be used, but it is VERY important that the edge contacting the sign has NO rough areas, or you may damage your sign. I use a purpose made vinyl sign applicator. Once again, you have a choice here. Some come with a layer of felt on one end, to minimise potential for sign damage. This is my personal preference. They are inexpensive and can be found on internet auction sites (you know the ones I mean!) all the time. They are only a few dollars each. Although other things can be used instead, I would highly recommend purchasing one of these applicators. They last indefinitely if used carefully. When I first started making vinyl signage, over 20 years ago, applicators didn't have the felt!
For convenience, you may wish to purchase a sigm application kit. This one is around $20 - 30 including postage.
Once you have squeegeed the sign completely, you can begin removal of the backing tape. As I have said, I prefer the paper type, and here's why. I spray some leftover application fluid (or just water might be best) onto the surface of the tape, and wait a minute of two. It makes removal of the tape much, much, easier. Gently start lifting the backing tape from one end or edge. You should do so in a manner that allows you to look under the tape where it is coming away, to see if your lettering is lifting as well. If it is, stop immediately, and run the squeegee over the application tape again. Repeat the process until all tape has been successfully removed. Once it is lifted away, DO NOT SQUEEGEE AGAINST THE LETTERING ITSELF. If any further pressure is needed to keep lettering against the surface, and it shouldn't at this point, gently use a finger with the nail side acting as your squeegee. Be gentle for christ sake! You may ruin your good work if you press too hard.
At this point you should be finished. Don't get the vehicle wet, and don't put it in direct sunlight for several hours. Hopefully you won't have any air or fluid bubbles under your lettering, but it is quite possible this can happen. You can do one of two things. You can simply ignore the bubbles, and see if they resolve over a few days. Most small bubbles will disappear within a week. The vinyl will 'breathe', and fluid bubbles in particular will dry up. If the bubbles are bigger, or contain air, you can put a very small hole in the vinyl and let the air/fluid out by gently pressing towards the cut in the material. I use a scalpel point, but the sharp point of a box cutter blade or sharp pin will o the same thing. Be careful not to press hard enough to go into the paint surface beneath the vinyl. If done carefully, the cut or pin-prick will be virtually invisible.