The Tale of the Tape
Recent problems with 3M's blue tape remain a mystery, but there are some good alternatives available at reasonable prices. Intertape's ProMask Blue is a top option, and the real bargain is electrical tape.[IMGCAP(1)
]Early last summer, we received a letter from a reader in Florida indicating that he'd experienced problems while using the popular blue tape from 3M to mask his cabinhouse and protect it from the teak treatment solution he was using on his boat. We published that letter in our August 15 issue, and then as the weeks wore on, additional letters came in.
Several readers who wrote us claimed similar problems. In essence, the blue tape, when pulled off, was leaving a "gooey, adhesive residue," even after just a couple of days. (For the record, the product in question is called Scotch-Blue™ Painter's Tape for Multi Surfaces No. 2090, which is advertised as a "medium adhesion" tape, good for 14-day removal.)
Another reader, who said he also experienced similar problems with 3M's No. 2090 blue tape, informed us that he'd read on an environmental website about an alleged change 3M had made to the formula for the tape's adhesive, moving from a petroleum base to a water base. After he contacted 3M representatives to discuss the problem, they told him that they would need additional information regarding his application to fully understand the problem. But they denied that there had been a change of formula, saying that the adhesive in the blue tape has always been water-based and remains so.
Having used this tape ourselves in past projects, we were concerned that it was failing for many readers. Was it simply a bad batch? Was the tape reacting with that particular teak treatment? Or was there something else going on? We figured it was time to get involved.
3M's website advertises the No. 2090 tape as "removes cleanly without adhesive transfer or surface damage for up to 14 days, even in direct sunlight." After deftly navigating 3M's automated phone system (lots of '80s music to be sampled), we spoke with Todd Mathes, who works in the company's construction products laboratory. He told us "The tape formulation is the same it has always been. There haven't been any major changes that would affect the overall tape performance." He allowed that the "clean removal" claim was raised from 7 to 14 days four years ago, but explained that this was simply a packaging change.
Mathes wasn't certain what might have caused the residue problems our readers experienced. He suspected the key to the problem might involve the solvents in the products that they used along with the tape—in the case of the first letter, Cetol. "We do not recommend the use of 3M Scotch-Blue Multi-Surface Painter's Tape with lacquers because we know that the acrylic adhesive [in the tape] and the solvents used in many lacquers are not compatible." Instead, Mathes recommended other tapes from 3M that use a rubber-based adhesive.
With all that in mind, we opted to run our own test.
What We Tested
We gathered up rolls of the following products specifically manufactured for masking projects: 3M Scotch Brand blue tape No. 2090, 3M Scotch Brand No. 233+ green tape, 3M Scotch Brand No. 256 green tape, 3M Scotch Brand No. 218 Fine Line tape, Intertape ProMask Blue, Intertape ProMask Green, and Inter-tape plain Masking Tape. For good measure, we threw in a roll of black electrical tape, which can be purchased at most hardware and home stores. Why? Because a local varnishing professional, Sally Dumas, told us that she has used black electrical tape as a masking tool for years. "Using black electrical tape is my most closely guarded secret. The only tape that I use is Manco," which she claims is available at Lowes home stores (We were unable to obtain Manco electrical tape and substituted a garden variety sold at Dollar General Stores.)
"The drawback is that you have to cut it with a knife," explained Dumas, "you can't tear it, but if you're doing angles on a boat, you can use one piece of tape to go around corners and this tape easily conforms. It's not good stuff on nonskid because you can't get a good seal, and I do not recommend it for painting because it's hard to lay out in a straight line. But temperature isn't a factor with this tape. I've used it for masking in weather from 30 to 90 degrees."
We might have included other products in our test, but we chose to keep our group to a manageable number. 3M does manufacture other tapes for extended outdoor use. They make a 2080 Masking Tape rated for 60 days. Another product that appears promising is a "blue tape" manufactured by Henkel Consumer Adhesives, marketed under the Duct Brand and sold at WalMart and other stores. One PS reader wrote to us that he'd had success using this product, which retails for less than $3 a roll.
How We Tested
On the first clear day of September, after three weeks of rainy weather borne of a hyperactive hurricane season in the southeast, we prepped an open section of hull on our test boat—a Trikala 19 trailerable trimaran. First we washed the section with warm water and a household dish detergent (Ajax), and thoroughly rinsed and dried it. Then we wiped that area with commercial grade Fantastic, and rinsed and dried it. And finally we cleaned the same area with Mary Kate Cleaning Detail (specifically for non-skid, but we had it on hand, so why not). We then rinsed the area again with fresh water and toweled it dry.
The boat spent the entire duration of the test parked in a suburban driveway, with the test patch oriented to the east, exposed to full sun for about four or five hours in the early part of the day. On the day we applied the tapes, we gauged the ambient temperature and humidity using our Thermo-Hygrometer from Radio Shack. With the temperature hovering in the low 80s (averaging 83° over an hour and a half it took to prep and apply the tapes) and the humidity averaging 73%, we applied the eight tape specimens, each three times in lengths approximately six inches long. We used a clean pair of scissors to make each cut, and we carefully wiped our hands between handling each different specimen. (Granted, most users will hand-tear the tape they use in masking projects, but for this test we wanted to minimize the introduction of additional factors like the oil found on human skin as well as the possible mixing of adhesives from one tape to the next.)
We inspected the specimens at three different intervals (24 hours, 6 days, and 10 days), each time removing a sample of each product from the hull to see what, if any, residue remained on the hull. Between inspections, we let the elements have their way. During the test there were dewy mornings, rainy and windy afternoons, and hot and humid days, just about what your boat would experience this time of year whether it was parked in a marina or a boat yard anywhere in the southeast. We even had some road dust, stirred up by passing traffic, and were thus unintentionally able to mimic the dusty conditions in some boatyards.
We also consulted a neighbor of ours, a painting contractor, who regularly uses 3M's 2090 blue tape, albeit in the two-inch variety. Experience has taught him, he claims, that using the tape on hot sunny days can cut the lifespan of its adhesive by 50%. He also said that the adhesive lasts less time if the tape is stepped on once its applied. The other element he cautioned us to consider when using this tape is the introduction of chemicals. If you're using the tape, as one reader was, to protect your gelcoat from something like Cetol, you should be careful to check in advance how the Cetol will react with the tape's adhesive. You can do this by masking off a test area in advance.
We later applied the same eight tapes to a piece of gelcoated fiberglass and painted the area within each taped rectangle with Cetol. The objective here was to determine how the Cetol reacted with each product's adhesive. Admittedly there are many substances other than Cetol that a boat owner would use with tapes (varnish, topside paint, etc.), so this remained a purely experimental aspect of our test.
After 24 Hours—The following day was overcast, with lots of dew on the boat. The Thermo-Hygrometer read 74.7° F with 96% humidity. We began by pulling the 3M No. 2090 Painters' Tape off and proceeded in sequence. That tape came off easily and cleanly and left no residue. Though some of the tapes were a little more resistant when pulled off, only three of them left any residue. Not unexpectedly, the worst was the Intertape masking tape, which most sailboat owners wouldn't use anyway; it's not recommended for outdoor use and was only included in our test as a common reference. More than 90% of the Intertape masking tape stayed on the hull, and that residue was resistant to cleaning. Ultimately we resorted to chemicals (denatured alcohol) for removal. The black electrical tape left only minimal traces of glue residue at either end of the tape segment, and those were easy enough to clean off with warm water and a sponge. The big surprise, however, was the amount of residue left behind by our most expensive tape—3Ms No. 256. More than 50% of the area under the tape was covered with adhesive residue when we removed the tape. The good news was that the residue came off relatively easily when we cleaned with the abrasive side of a sponge and warm water.
After 6 Days—We pulled the next batch of test specimens after six days out in the elements. Some of these tapes aren't rated for extended use, and others aren't rated for outdoor use, but we found some surprises.
It was an overcast, drizzly day with 70.5° F temperature and 97% humidity. Again, working through our line-up beginning with the 3M No. 2090 Blue Painters' Tape, this product required a little persistence to begin peeling, but was easy to remove thereafter, leaving minimal residue. The 3M green tape No. 233+ proved very tough to pull, and the paper backing separated. This tape left a little more residue. 3M's No. 256 green tape was also tough to pull, and again the paper backing separated from the glue, leaving an estimated 50% of the glue as residue on the hull (easily visible in the photo at right). The Scotch Brand Fine Line No. 218 tape removed relatively easily, but left a thin layer of adhesive residue over the entire area where the tape had been applied to the hull's surface. The Intertape ProMask Blue was easy to remove, but the tape did tear. However, this product left no residue on the surface. The Intertape ProMask Green was very tough to remove and the paper backing tore easily, but this tape also left no residue on the hull. The Intertape plain masking tape was very resistant to removal and left a big mess of residue on the hull. (This was again the most difficult to remove.) The black electrical tape removed with little effort, revealing a completely dry, unblemished portion of the hull, although there were traces of residue from the tape's adhesive at the very top edge of the tape. Removing that residue was a simple matter of washing it with warm, soapy water and a sponge.
After 10 Days—The 10th day was clear, but cooler. The humidity was 80% and the temperature was 80° F. As we wrote above, the days in between our three pulls produced varied weather. We pulled the final batch of tape and discovered the following: 3M's No. 2090 Painter's Tape pulled easily and cleanly with just a small bit of residue remaining at the ends. 3M's No. 233+ was harder to pull and left approximately 50% of the area covered in a thin layer of residue. 3M's No. 256 green tape pulled easily and left a light residue. (This suggests that the ambient temperature at the time you pull off the tape can make a big difference. For instance, tape can come off poorly if there's been a heavy dew and you pull it off in the hot morning sun.) The 3M No. 218 Fine Line tape was easy to pull and left a full section of light residue that proved easy to clean. Intertape's ProMask Blue came off easily and cleanly as well, with residue remaining only at the edges.
Interape's ProMask Green was easy to pull, but left a heavy residue over 30% of the area underneath the tape. The Intertape masking tape was very stubborn and didn't come off except for scrubbing and the use of more denatured alcohol. The electrical tape pulled off easily and left only a slight bit of residue around the edges, which was easily cleaned.
One of the readers who initially wrote to us regarding problems he experienced with 3M's blue tape, had used that product to mask the gelcoated surface of his boat as a protective measure from the wood treatment he was using at the time—Cetol. It seemed possible that one or more of the Cetol's ingredients might have reacted with the tape's adhesive to create the gummy residue. When we contacted Sikkens (the makers of Cetol) to investigate this possiblity, their representative told us "we are not aware of any problems with our products when used with painters tape." Nonetheless, we thought that testing all the tapes with Cetol might be instructive.
To conduct this portion of our test, we prepped a panel of gelcoated fiberglass using the same three-step cleaning process that we used on the hull. Then we masked off rectangular areas using each of the tapes, and painted the interior area of each with Cetol Clear Gloss. We applied only one coat, though the manufacturer suggests three, but we were coating gelcoat, not wood. Our only interest was to determine if the adhesive on any of the tapes would have an adverse reaction with the Cetol, and after three days, none did.
Though we found traces of adhesive residue beneath 3M's 2090 Painters' Tape after the 6- and 10-day phases of our test, we didn't experience the severe problems mentioned by several readers whose e-mails prompted us to initiate our test. And the residue we saw was readily removed with standard cleaning methods. Nothing unusual here.
Our results didn't surprise 3M's Todd Mathes. He told us: "It can be difficult to pinpoint and duplicate how or why your readers had a problem with the tape. There are many factors that can have a profound effect on tape performance including temperature, humidity, time left on the surface, the substrate being taped upon, the coating being put over the tape, potential contaminates, tape removal methods (tape removal angle can be very important to adhesive transfer and substrate damage), UV light, and application of the tape, etc." He cautioned us that 3M's tape products should be used within one year of purchase, and be stored in a cool, dry place because heat can affect the chemical makeup of the adhesive and thus the tape's performance.
Despite the acceptable results we had with 3M's No. 2090 Painters' Tape, it wasn't the best overall performer in our test. That honor went to Intertape's ProMask Blue. This product is almost identical in appearance to 3M's No. 2090 tape, but it outperformed its better-known rival by a small but measurable margin, particularly in the 6-day pull. (In our Cetol test, after 3 days, it was clearly the easiest to pull and by far the cleanest.) The fact that Intertape's product sells for 30 percent less than 3M's blue tape makes it a clear choice as our winner.
For those readers who truly want to economize on masking projects, we see no reason not to use black electrical tape. The disadvantages—that some residue will develop along the edges and you'll need to use a knife or scissors to cut the tape—hardly seem to outweigh the significant cost advantages it offers. Calculated as a cost-per-foot comparison, the black electrical tape we tested—at 1 cent per foot—is definitely a Best Buy. Intertape's ProMask Blue is 1.85 cents per foot; 3M's No. 2090 Painters' Tape is 2.75 cents per foot; and that company's No. 256 green tape, which apart from the plain masking tape was the poorest performer in our tests, sells for a whopping 9.5 cents per foot.
The results of our test are instructive if not wholly definitive. Another varnish professional we checked with—Karen Russell, who boasts 30 years experience in the trade—said she only uses 3M products. "Everybody's got their own preference," she explained of her colleagues. Russell likes the green No. 256 tape. "It's expensive," she allowed, "and it leaves a little residue, but that always cleans up easily with Oops, and I can keep it on beyond the 14-day limit of the blue tape."
Our investigations continue.
Also With This Article
"Masking Tape: Value Guide"