Problem – Clear Coat over pinstripe causes edge bubbles

Tags: Clearcoat

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http://www.howtopaintcars.com/wp-content/gallery/paint-materials/3m-plastic-striping-tape.jpg?i=1766741799Recently a friend told me of a problem he had when painting a motorcycle gasoline tank.

It seems that he wanted to protect his tape pinstripes with clear so that they would not peal if some gasoline happened to get on them when he was refilling his tank.

This might sound like a great idea at first because the pinstripes can be used to hide problems between edges of color coat. Its an easy way for someone who is not skilled in painting pinstripes to add detail but unfortunately you can run into a lot of problems including immediate failure due to solvents like he did or shorter life cycle due to difference in the substrate density. You can think of that second problem in the sense of putting a bed pillow in a concrete sidewalk while its being poured. Eventually its going to fail.

If you are successful in not having solvent problems you also risk the problem of runs or sags as the pinstripe will cause a buildup of material on the top which will run as more coats are applied.

If you think that you just must clear over your pinstripes the best method would be to apply a full coat of clear to your base coat then allow it to dry. This is one problem that my friend had he simply applied the tape to his base coat which was not single stage. This probably increased the problem of lifting and bubbling.

Once the first coat of clear has dried you can apply your pinstripe then paint the surface with a half coat or tack coat and allow it to dry. This will seal the edge of the pinstripe tape.

After you have allowed everything to flash and waited a good hour for solvents to escape you can then continue with a few full clear coats.

Again you must realize that this really is not optimal.

When pinstripes are applied to vehicles they are normally applied to the final surface of the clear or paint. Vinyl tape used for Pinstripes has adhesive that is formulated for extended adhesion over many years with constant contact to the elements but it is not painters tape that is designed for good edge holdout.

Another option you have if you can not paint pinstripes by hand is to use a fine line painters tape that can mask over a color that you apply first or a tape that has a removable center which will allow you to mask around the line.

Painting the line first and masking it with a single piece of tape is definitely easier then masking around a line. If you were restoring a vehicle that has a wide racing stripe with a smaller 1/4″ line around the outside I would definitely paint the stripe first then mask it then paint the overall color and remove the tape after the base coat has flashed for about 5 minutes. This will allow the edges to run out and you will have smooth transitions before you apply your clear.

 

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