Removing Rock Hard Tape Adhesive

 Application Tape Tip

Every so often, I get a service call involving a sign maker or painter, who cannot remove the adhesive of our application tape from a substrate. I just receive one yesterday from a woman in southern California, who had left masked painted panels in the sun. The panels became so hot that she could not handle the substrate without wearing gloves. The scorching summer heat had baked on the masking.

Many of our customers use our paper application tapes as a protective masking for substrates or for painting.  Masking on products stored indoors and not exposed to high heat should remove without problems.  When paper application tape is exposed to high heat and prolonged sunlight, however, you can encounter big trouble that may be irreparable.

In another case, an automotive painter used our application tape to mask the chrome bumpers of a classic car, while he was spraying paint. This is a great application for the product.  The problem occurred, when he failed to remove the tape after painting. After he finished the job, the car was left outside for weeks. In that time the adhesive hardened. He tried everything to remove the masking, including water, mineral spirits, turpentine, lacquer thinner and naptha. While the paper eventually came off, the adhesive still remained. No amount of solvent could dissolve the adhesive.

Here’s what we think is happening. With exposure to heat and UV light the coadhesive strength of the rubber adhesive increases, until it crystallizes and hardens.  As the adhesive hardens, it becomes less and less soluble. At some point in time, the adhesive becomes so hard that it loses any solubility at all.

Once the adhesive becomes hard as a rock, you are all out of luck. At RTape we have tested a wide range of solvents, hoping to find that one chemical which will remove hardened adhesive. Neither we nor any other of the manufacturers have discovered that magic potion. The good news is that if you have masked glass and the adhesive hardens, you can at least scrape the residue off with a razor scraper. That’s as good as it gets, unfortunately.

The only advice that I can give you is:·
  • Do not store masked materials outdoors or exposed to high heat.
  • If you are using application paper as a masking for painting, remove the masking when you are finished painting.

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