Whether you laminate application tape by hand or with a laminator, avoid trapping air bubbles between the vinyl graphics and the application tape. Bubbles and wrinkles in the application paper often result in bubbles and wrinkles in the applied graphic, regardless of the skill and effort of the installer. If you inspect the adhesive side of a graphic, after removing the release liner, you often can see the formation of wrinkles and bubbles in the adhesive. In the application process, you will just transfer these wrinkles and bubbles to the substrate.
Removing Vinyl Graphics
The process of removing vinyl films generally requires the use of both heat and chemicals. Some removers contain hazardous chemicals, such as toluene, that can cause health problems. Before using any chemical remover, read the manufacturer’s MSDS sheet and instruction bulletin. Always wear the recommended safety equipment.
When working with propane torches or heat guns, use caution. Heat sources can raise the temperature of the substrate hot enough to blister or burn your fingers. Careless use of heat sources can also cause fires and explosions.
Removing graphics is unpredictable. Film from the same roll of vinyl, applied to different substrates will remove with various degrees of difficulty. A variety of factors determine how easily graphics can be removed. These factors include the age of the graphic and the substrate’s condition at the time of application.
Adhesion increases with time making removals increasingly difficult the longer that a graphic is on the substrate. Graphics applied to newer and smoother factory-paint finishes remove more easily, than those applied to old, pitted surfaces. A rough finish provides the adhesive with a greater total surface area for a stronger adhesive bond.
The first step in the removal process is to heat to the graphics. Heat softens the facestock and its adhesive allowing the vinyl to be more easily peeled from the surface. By getting a large area hot you can peel larger pieces of film off at one time.
If you are removing small letters, a small handheld propane torch or industrial heat gun provides sufficient heat. If the graphics cover a large area, however, you will need much larger torch, such as a weed burner. With an extra-long hose, the propane tank can be left on the ground, safely leaving the scaffolding free of clutter.
Heat a large section of the truck surface for approximately one minute. Keep the flame moving, so you do not to burn the vinyl or substrate. Use caution when heating graphics on plastic substrates. Heat can warp the substrate.
After heating, use a fingernail, a Teflon®-coated plastic scraper, such as the Lil Chizler, or a plastic blade to lift the graphic’s edge. When lifting the vinyl from the surface, pull the film at a low angle (preferably less than 45°) close to the work surface.
Whether you use a heat gun, propane torch or steamer, the secret is to apply the correct degree of heat, something that can only be learned by trial and error. If the vinyl is too hot or too cold, not only will you leave the adhesive, but the film itself will break into little pieces. At the optimal temperature, the film will remove more easily, in large pieces and you will reduce the time it takes to perform the removal.
To remove the adhesive residue, after film removal, requires the use of a chemical adhesive remover. Keep a variety of chemicals with you, including PrepSol™, kerosene, lacquer thinner, xylene and a citrus-based remover, when going on a removal job. What works wonders one day, may not work the next.
Start with a less aggressive and safer remover, such as Rapid Remover, before trying the stronger and usually more toxic chemicals. Using this approach reduces the risk of paint damage and minimizes any health hazards.
Before using removers, always test the chemical on an inconspicuous spot of the substrate to make sure the remover doesn’t react with the paint. Repainted vehicle surfaces are especially susceptible to damage from chemical removers.
Spray the remover on the adhesive residue. Wait for the chemical to react with the adhesive residue. When the adhesive softens to a jelly-like substance, use a squeegee to scrape the gel from the surface. Old rivet brushes can scrub adhesive off the rivet heads.
Scraping off jellified adhesive is messy. To keep from spreading the mess all over the substrate, mask off the area around the graphic with masking tape and kraft paper or use RTape application tape. If you are removing large areas of adhesive, some of it will likely end up on the shop floor, so cover the area underneath your scaffold with brown kraft paper or application tape to aid clean up.
In some cases, adhesive residue remains on the surface. When this happens, spray the residue with remover, wait for the adhesive to soften, and wipe the surface clean with rags or paper towels. Finish cleaning the surface by wiping with isopropyl alcohol.
The surface must be perfectly clean before installing new graphics. Applying new vinyl over old adhesive practically guarantees film failure, because the adhesive will absorb the chemicals like a sponge. If the new graphics are applied over the residue, the remaining remover will attack the new adhesive. This can cause new vinyl to bubble, peel or fall off.
For some removal jobs, using heat is impractical. For example, heating a window with a torch can result in glass breakage. When you cannot use heat, try using razor scrapers and plastic abrader wheels to aid film removal.
This article was written by Jim Hingst, Business Development Manager-Technology for RTape Corp. and posted on Hingst Sign Post.