In most cases, graphic failure is caused by a misstep in the installation process-and a good portion of those missteps can be traced to insufficient surface prep. Therefore surface prep is an absolutely vital step in every type of graphic vinyl wrap application.
I believe it’s our responsibility, as wraps professionals, to inform the customer to bring us a clean vehicle, high pressure soap and water washed (no wax) from the day prior. The customer will not “get a cookie” for bringing it to the shop in the condition that we need it in. But, he may be charged additional shop labor rates ($60-$80 per hour usually), if additional prep work is needed. Enforce this rule! Dirt on the ground in the work area can very easily get sucked back up behind the film due to static.
The Inspection Record
A pre-installation inspection record will need to be filled out prior to taking possession of the vehicle. This inspection record is for you, (the wrap shop’s protection). This record generally consists of a visual inspection of the surface, verifying the working order of lights and electrical components, along with a paint bond “610 tape test,” a media specific sign-off sheet, and photo reinforcements. During this inspection, the installer may find surface flaws, and/or less than O.E.M. caliber paint bond. All the worst case scenarios of radical paint failure must now be explained to the customer and more importantly, a signed and dated waiver must be obtained relieving the wrap shop of responsibility of clean removability and/or damage to existing paint upon removal or even repositioning in those specifically noted panels.
Just because the vehicle is brand new doesn’t mean it’s perfect. When a lot attendant scratches a new car’s bumper, they will have an airbrush painter come out to feather in a touch up job on the spot and just let it air dry. These are potentially weak areas for us, and can a lot of times be found by taking a smooth dry rag and rubbing from one side of the bumper around to the opposite side, feeling for differences in friction along the way. It doesn’t matter if it’s more drag or less drag, if it’s on the same panel, you can assume that there’s been work done in that area. Any panel that has had body shop work and or re-paints will most times not be given the full warranty that O.E.M. panels are, because we cannot verify the integrity of the body shop’s work to the original manufacturers spec in most cases. When appropriately explained prior to a job starting, customers most often understand. It’s the customers that haven’t been fully educated that end up being the non-stop pains in our necks!
Begin Your Prep
An alcohol wipe-down is generally the very first step-and the last step in surface prep. In fact, you can’t do this step enough. You should be panel washing with alcohol as you go to keep your own oily finger prints off the vehicle’s surface. Treat your hands and forearms with isopropyl alcohol roughly every hour as well to keep them disinfected and oil free during the times that you are working with wrap films. Also, men with hairy arms should try to rip free any loose arm hair at this point as well or else it will end up under your wrap, and will invariably end up in the most noticeable spot. If you tend to sweat a lot, you will need to keep that in check with alcohol as well (sweat seems to kill adhesive right on the spot.)
Prep Chemicals and Tools
I prefer isopropyl alcohol over denatured. The big argument for denatured is that it removes adhesives, tar, and surface debris better and faster than isopropyl. My advice, use both. Denatured is better for the tough dirt and grime scrubbing, but might have unwanted reactions to your film or adhesive. Isopropyl is better for that surgically sterile final wipe down that won’t deteriorate your adhesive just prior to the graphic application.
Prep-Sol is the probably the most undervalued and underused chemical in wrap prep. DuPont’s Prep-Sol 3919S is a solvent specifically designed to cut through and remove grease, tar, exhaust buildup, silicone, waxes, and even adhesives from the vehicle’s surface, while being much safer on the paint than xylene-based products. I like to apply my Prep-Sol with a heavily saturated wet cloth in small circular motions nice and sure into the surface, and wipe off with a dry cloth in that same “Karate Kid wax-on wax-off motion.” Prep-Sol tends to leave what it has pulled up on the surface, and will need to be gone over again with heavy saturation isopropyl for your final alcohol wipe down, to avoid any contaminated areas.
Xylene is the toughest solvent that I care to use in the wrap shop. Save this as a last resort only after determining that denatured alcohol and Prep-Sol haven’t worked sufficiently. Xylene is commonly used as a paint thinner and to clean painting equipment. What this means to us is that it’s the most likely thing to damage the existing finish of the panel we are applying to. If you have decided use xylene, always spot-check a low, out-of-sight inconspicuous area to test for discoloration, or removal of clearcoat. If the spot test passes go ahead and use it only where needed. Never do a full panel wash with xylene. Immediately after using xylene, get it off the surface with a very thorough alcohol wipe-down. Never let xylene sit for too long on a painted surface.
People often ask if they should use clay bar detailing products. Yes! Totally! It’s not going to be something you generally do for the giant fleet of paneled plumbing vans, but when you do a high-end, super detailed custom finish wrap job, even the tiniest bumps and imperfections will stick out like a sore thumb.
To determine if a detailing clay should be used or not, put your hand in a regular grocery store plastic bag, and rub the surface of a clean panel, if it feels sandy you could benefit from using this product. If you do decide to use a clay bar as part of your surface prep, you should do it early on in the steps-after the soap water wash and 1st alcohol wipe down, but before the use of Prep-Sol.
The Final Step
The final step when preparing the vehicle’s surface to receive wrap film is to apply an adhesive bond promoter to any anticipated high-stress areas or cutlines in the panel, giving the film some attributes most commonly associated with permanent adhesive films. Keep in mind that using an adhesive bond promoter will likely negate any “reposition-ability and “clean removability” attributes the wrap film might have. The three things that will guarantee an adhesive transfer between film and substrate are heat, pressure and time. Although, use of an adhesive bond promoter is usually required to stay within warranty specifications of a number of wrap films, a little goes a long way. Use bond promoter sparingly and take precautions.